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  • More Fun with C# Iterators and Generators

    - by James Michael Hare
    In my last post, I talked quite a bit about iterators and how they can be really powerful tools for filtering a list of items down to a subset of items.  This had both pros and cons over returning a full collection, which, in summary, were:   Pros: If traversal is only partial, does not have to visit rest of collection. If evaluation method is costly, only incurs that cost on elements visited. Adds little to no garbage collection pressure.    Cons: Very slight performance impact if you know caller will always consume all items in collection. And as we saw in the last post, that con for the cost was very, very small and only really became evident on very tight loops consuming very large lists completely.    One of the key items to note, though, is the garbage!  In the traditional (return a new collection) method, if you have a 1,000,000 element collection, and wish to transform or filter it in some way, you have to allocate space for that copy of the collection.  That is, say you have a collection of 1,000,000 items and you want to double every item in the collection.  Well, that means you have to allocate a collection to hold those 1,000,000 items to return, which is a lot especially if you are just going to use it once and toss it.   Iterators, though, don't have this problem.  Each time you visit the node, it would return the doubled value of the node (in this example) and not allocate a second collection of 1,000,000 doubled items.  Do you see the distinction?  In both cases, we're consuming 1,000,000 items.  But in one case we pass back each doubled item which is just an int (for example's sake) on the stack and in the other case, we allocate a list containing 1,000,000 items which then must be garbage collected.   So iterators in C# are pretty cool, eh?  Well, here's one more thing a C# iterator can do that a traditional "return a new collection" transformation can't!   It can return **unbounded** collections!   I know, I know, that smells a lot like an infinite loop, eh?  Yes and no.  Basically, you're relying on the caller to put the bounds on the list, and as long as the caller doesn't you keep going.  Consider this example:   public static class Fibonacci {     // returns the infinite fibonacci sequence     public static IEnumerable<int> Sequence()     {         int iteration = 0;         int first = 1;         int second = 1;         int current = 0;         while (true)         {             if (iteration++ < 2)             {                 current = 1;             }             else             {                 current = first + second;                 second = first;                 first = current;             }             yield return current;         }     } }   Whoa, you say!  Yes, that's an infinite loop!  What the heck is going on there?  Yes, that was intentional.  Would it be better to have a fibonacci sequence that returns only a specific number of items?  Perhaps, but that wouldn't give you the power to defer the execution to the caller.   The beauty of this function is it is as infinite as the sequence itself!  The fibonacci sequence is unbounded, and so is this method.  It will continue to return fibonacci numbers for as long as you ask for them.  Now that's not something you can do with a traditional method that would return a collection of ints representing each number.  In that case you would eventually run out of memory as you got to higher and higher numbers.  This method, though, never runs out of memory.   Now, that said, you do have to know when you use it that it is an infinite collection and bound it appropriately.  Fortunately, Linq provides a lot of these extension methods for you!   Let's say you only want the first 10 fibonacci numbers:       foreach(var fib in Fibonacci.Sequence().Take(10))     {         Console.WriteLine(fib);     }   Or let's say you only want the fibonacci numbers that are less than 100:       foreach(var fib in Fibonacci.Sequence().TakeWhile(f => f < 100))     {         Console.WriteLine(fib);     }   So, you see, one of the nice things about iterators is their power to work with virtually any size (even infinite) collections without adding the garbage collection overhead of making new collections.    You can also do fun things like this to make a more "fluent" interface for for loops:   // A set of integer generator extension methods public static class IntExtensions {     // Begins counting to inifity, use To() to range this.     public static IEnumerable<int> Every(this int start)     {         // deliberately avoiding condition because keeps going         // to infinity for as long as values are pulled.         for (var i = start; ; ++i)         {             yield return i;         }     }     // Begins counting to infinity by the given step value, use To() to     public static IEnumerable<int> Every(this int start, int byEvery)     {         // deliberately avoiding condition because keeps going         // to infinity for as long as values are pulled.         for (var i = start; ; i += byEvery)         {             yield return i;         }     }     // Begins counting to inifity, use To() to range this.     public static IEnumerable<int> To(this int start, int end)     {         for (var i = start; i <= end; ++i)         {             yield return i;         }     }     // Ranges the count by specifying the upper range of the count.     public static IEnumerable<int> To(this IEnumerable<int> collection, int end)     {         return collection.TakeWhile(item => item <= end);     } }   Note that there are two versions of each method.  One that starts with an int and one that starts with an IEnumerable<int>.  This is to allow more power in chaining from either an existing collection or from an int.  This lets you do things like:   // count from 1 to 30 foreach(var i in 1.To(30)) {     Console.WriteLine(i); }     // count from 1 to 10 by 2s foreach(var i in 0.Every(2).To(10)) {     Console.WriteLine(i); }     // or, if you want an infinite sequence counting by 5s until something inside breaks you out... foreach(var i in 0.Every(5)) {     if (someCondition)     {         break;     }     ... }     Yes, those are kinda play functions and not particularly useful, but they show some of the power of generators and extension methods to form a fluid interface.   So what do you think?  What are some of your favorite generators and iterators?

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  • Top 10 Browser Productivity Tips

    - by Renso
    Originally posted on: http://geekswithblogs.net/renso/archive/2013/10/14/top-10-browser-productivity-tips.aspxYou don’t have to be a geek to be a productive browser user. The tips below have been selected by actions users take most of the time to navigate a web-site but use long-standing keyboard or mouse actions to get them done, when there are keyboard short-cuts you can use instead. Since you hands are already on the keyboard it is almost always faster to sue a keyboard shortcut to get something done that you usually used the mouse for. For example right-clicking on something to copy it and then doing to same for pasting something is very time consuming, keyboard shortcuts have been created that simplify the task. All it takes are a few memory brain cells to remember them. Here are the tips, in no particular order:   Tip 1 Hold down the spacebar on your keyboard to page to the end of your web page rather than using your mouse. This is really a slow way of doing it. If you want to page one page at a time, hit the spacebar once, and again to page again. But if you want to page all the way to the end of the web page simply hit Ctrl+End (that is hold down the Ctrl key and hit the End button on your keyboard). To get to the top of your web page, simply hit Ctrl + Home to go all the way to the top of your web page. Tip 2 Where are my downloads? Some folks run downloads again-and-again because they do not know where the last one went and they do not see the popup, or browser note on their web page in the footer, etc. Simply hit Ctrl+J. Works in most browsers. Tip 3 Selecting a US state from a drop down box. Don’t use the mouse, takes just way too long to scroll. When you tab to the drop down box or click on it with your mouse, simply hit the first character of the state and it will be selected. For Texas for example hit the letter “T” twice on your keyboard to get to it. The same concept can be applied to any drop down box that is alphabetical or numerically sorted. Tip 4 Fixing spelling errors. All modern-day browsers support this now. You see the red wavy lines underscoring a word, yes it is a spelling error. How do you fix it? Don’t overtype it or try and fix it manually, fist right-click on it and a list of suggestions comes up. If it does not show up, like my name “Renso” and you know how to spell your name as in this example, look further down the list of options (the little window popup that appears when you right click) and you should see an option to “Add to Dictionary”. Be warned, when you add it, it only adds it to the browser you’re using’s dictionary. If you use Google Chrome, Firefox and IE, each one will have their own list. Tip 5 So you have trouble seeing the text on the screen. Or you are looking at a photo, for example in Facebook. You want to zoom in to read better or zoom into a photo a bit more. Hit Ctrl++ (hold down Ctrl key and hit the plus key – actually it’s the equal key but it is easier to remember that it is plus for bigger). Hit the minus to zoom out. Now you can’t remember what the original size was since you were so excited to hit it 20 times, or was that 21… Simply hit Ctrl+0 (that is zero) and it will reset it to the default. Tip 6 So you closed a couple of tabs in your browser. Suddenly you remember something you wanted to double-check something on one of the tabs, you cannot remember the URL ad the tab is gone forever, or is it? Simply hit Ctrl+Shift+t and it will bring back your tabs one by one each time you click the T. This has also been a great way for me to quickly close some tabs because I don’t want my boss to see I’m shopping and then hitting Ctrl+Shift+t to quickly get it back and complete my check-put and purchase. Or, for parents, when you walk into your daughter’s room and you see she quickly clicks and closes a window/tab in here browser. Not to worry my little darling, daddy will Ctrl+Shift+t and see what boys on Facebook you were talking too… Tip 7 The web browser is frozen on your PC/Laptop/Whatever, in this example it may be your Internet Explorer browser. I don’t mention Firefox or Chrome here because it probably never happens in their world. You cannot close it, it won’t respond to anything you have done s far except for the next step you are about to take, which is throw your two-day old coffee on your keyboard. This happens especially on sites that want to force you to complete a purchase order. Hit Ctrl+Alt+Del on your keyboard on any version of windows, select TASK MANAGER. In the  First Tab, which is the Process Tab, look for the item in question. In this example you should see Internet Explorer. Right-click it and select “End Task”. It will force the thread out of memory and terminate that process. You can of course do this with any program running under your account. Tip 8 This is a personal favorite of mine. To select words in the paragraph without using the mouse. You don’t want to select one character at a time like when you use the Ctrl+arrows as it can be very slow if you want to select a lot of text. You also want to select whole words. Simply use the Ctrl+Shift_arrow (right or left depending which direction you want to go. Tip 9 I was a bit reluctant to add this one, but being in the professional services industry still come across many-a-folk that simply can’t copy-and-paste them-all text or images that reside on them screens, y’all. Ctrl+c to copy and Ctrl+v to paste it. Works a lot faster than using the mouse. You may be asking: “Well why in the devil did they not use Ctrl+p for paste…. because that is for printing. This is of course not limited to the browser world, it applies to almost any piece of software running on PC or Mac. Go try it on an image on your browser, right-click it and select copy. Open a word document and Ctrl+v to paste the image in there. Please consider copyright laws. Tip 10 Getting rid of annoying ads. Now this only works when you load a web page, meaning when you get back to the same page later you will have to do this again and you will need to learn a tool to do it, WELL WORTH IT. For example, I use GrooveShark to listen to music but I don’t like the ads they show. Install a tool like Firebug for Firefox or use the Ctrl+Shift+I on Chrome to bring up the developer toolbar. Shows at the bottom of the page. With Firefox, once you have installed Firebug as an add-on, a yellow bug should appear on the top right-hand-side of your browser, click on it to display the developer toolbar. You will need to learn how to use it, but once you know how to select an item/section on the window (usually just right-click the add you don’t want to see and select “Inspect Element”, the developer toolbar will appear (if not already there)) and then simply hit delete and it will remove the add from the screen. If you don’t know HTML you may need to play with it a bit, but once you understand how it works can open up a whole new world for you on how web pages actually work. If you can think of any others that have saved you a ton of time please let me know so I can add them to a top 99 list.

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  • How to set Grub to automatically load Xen kernel

    - by Cerin
    How do you configure Grub to automatically use the Xen kernel under Ubuntu 11.10? No matter what I do, it loads the first menuentry. The only way I can get it to load Xen is to manually select the kernel, which I can't do if I have to reboot the server remotely, or there's a power failure and the machine automatically boots up when power's restored, etc. It's driving me nuts. In my /boot/grub/grub.cfg, the Xen kernel is at index 4 (i.e. it's the 5th menuentry). So I've tried: Setting GRUB_DEFAULT=4, and running sudo update-grub Setting GRUB_DEFAULT=saved and GRUB_SAVEDEFAULT=true, and running sudo update-grub Setting GRUB_DEFAULT="Ubuntu GNU/Linux, with Xen 4.1-amd64 and Linux 3.0.0-16-server", and running sudo update-grub None of these work. It continues to load the first menuentry, which is "Ubuntu, with Linux 3.0.0-16-server". Below is my current /boot/grub/grub.cfg. What am I doing wrong? # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="Ubuntu GNU/Linux, with Xen 4.1-amd64 and Linux 3.0.0-16-server" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac set locale_dir=($root)/boot/grub/locale set lang=en_US insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=2 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### if [ ${recordfail} != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "$linux_gfx_mode" != "text" ]; then load_video; fi menuentry 'Ubuntu, with Linux 3.0.0-16-server' --class ubuntu --class gnu-linux --class gnu --class os { recordfail set gfxpayload=$linux_gfx_mode insmod gzio insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac linux /boot/vmlinuz-3.0.0-16-server root=UUID=d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac ro initrd /boot/initrd.img-3.0.0-16-server } menuentry 'Ubuntu, with Linux 3.0.0-16-server (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac echo 'Loading Linux 3.0.0-16-server ...' linux /boot/vmlinuz-3.0.0-16-server root=UUID=d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.0.0-16-server } submenu "Previous Linux versions" { menuentry 'Ubuntu, with Linux 3.0.0-12-server' --class ubuntu --class gnu-linux --class gnu --class os { recordfail set gfxpayload=$linux_gfx_mode insmod gzio insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac linux /boot/vmlinuz-3.0.0-12-server root=UUID=d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac ro initrd /boot/initrd.img-3.0.0-12-server } menuentry 'Ubuntu, with Linux 3.0.0-12-server (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac echo 'Loading Linux 3.0.0-12-server ...' linux /boot/vmlinuz-3.0.0-12-server root=UUID=d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.0.0-12-server } } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### submenu "Xen 4.1-amd64" { menuentry 'Ubuntu GNU/Linux, with Xen 4.1-amd64 and Linux 3.0.0-16-server' --class ubuntu --class gnu-linux --class gnu --class os --class xen { insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac echo 'Loading Xen 4.1-amd64 ...' multiboot /boot/xen-4.1-amd64.gz placeholder echo 'Loading Linux 3.0.0-16-server ...' module /boot/vmlinuz-3.0.0-16-server placeholder root=UUID=d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac ro echo 'Loading initial ramdisk ...' module /boot/initrd.img-3.0.0-16-server } menuentry 'Ubuntu GNU/Linux, with Xen 4.1-amd64 and Linux 3.0.0-16-server (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os --class xen { insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac echo 'Loading Xen 4.1-amd64 ...' multiboot /boot/xen-4.1-amd64.gz placeholder echo 'Loading Linux 3.0.0-16-server ...' module /boot/vmlinuz-3.0.0-16-server placeholder root=UUID=d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac ro single echo 'Loading initial ramdisk ...' module /boot/initrd.img-3.0.0-16-server } menuentry 'Ubuntu GNU/Linux, with Xen 4.1-amd64 and Linux 3.0.0-12-server' --class ubuntu --class gnu-linux --class gnu --class os --class xen { insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac echo 'Loading Xen 4.1-amd64 ...' multiboot /boot/xen-4.1-amd64.gz placeholder echo 'Loading Linux 3.0.0-12-server ...' module /boot/vmlinuz-3.0.0-12-server placeholder root=UUID=d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac ro echo 'Loading initial ramdisk ...' module /boot/initrd.img-3.0.0-12-server } menuentry 'Ubuntu GNU/Linux, with Xen 4.1-amd64 and Linux 3.0.0-12-server (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os --class xen { insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac echo 'Loading Xen 4.1-amd64 ...' multiboot /boot/xen-4.1-amd64.gz placeholder echo 'Loading Linux 3.0.0-12-server ...' module /boot/vmlinuz-3.0.0-12-server placeholder root=UUID=d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac ro single echo 'Loading initial ramdisk ...' module /boot/initrd.img-3.0.0-12-server } } ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod raid insmod mdraid1x insmod part_msdos insmod part_msdos insmod ext2 set root='(mduuid/be73165bc31d6f5cd00d05036c7b964f)' search --no-floppy --fs-uuid --set=root d72bad3f-9ed7-44b9-b3d1-d7af9f62a8ac linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ###

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  • Why Is Vertical Resolution Monitor Resolution so Often a Multiple of 360?

    - by Jason Fitzpatrick
    Stare at a list of monitor resolutions long enough and you might notice a pattern: many of the vertical resolutions, especially those of gaming or multimedia displays, are multiples of 360 (720, 1080, 1440, etc.) But why exactly is this the case? Is it arbitrary or is there something more at work? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites. The Question SuperUser reader Trojandestroy recently noticed something about his display interface and needs answers: YouTube recently added 1440p functionality, and for the first time I realized that all (most?) vertical resolutions are multiples of 360. Is this just because the smallest common resolution is 480×360, and it’s convenient to use multiples? (Not doubting that multiples are convenient.) And/or was that the first viewable/conveniently sized resolution, so hardware (TVs, monitors, etc) grew with 360 in mind? Taking it further, why not have a square resolution? Or something else unusual? (Assuming it’s usual enough that it’s viewable). Is it merely a pleasing-the-eye situation? So why have the display be a multiple of 360? The Answer SuperUser contributor User26129 offers us not just an answer as to why the numerical pattern exists but a history of screen design in the process: Alright, there are a couple of questions and a lot of factors here. Resolutions are a really interesting field of psychooptics meeting marketing. First of all, why are the vertical resolutions on youtube multiples of 360. This is of course just arbitrary, there is no real reason this is the case. The reason is that resolution here is not the limiting factor for Youtube videos – bandwidth is. Youtube has to re-encode every video that is uploaded a couple of times, and tries to use as little re-encoding formats/bitrates/resolutions as possible to cover all the different use cases. For low-res mobile devices they have 360×240, for higher res mobile there’s 480p, and for the computer crowd there is 360p for 2xISDN/multiuser landlines, 720p for DSL and 1080p for higher speed internet. For a while there were some other codecs than h.264, but these are slowly being phased out with h.264 having essentially ‘won’ the format war and all computers being outfitted with hardware codecs for this. Now, there is some interesting psychooptics going on as well. As I said: resolution isn’t everything. 720p with really strong compression can and will look worse than 240p at a very high bitrate. But on the other side of the spectrum: throwing more bits at a certain resolution doesn’t magically make it better beyond some point. There is an optimum here, which of course depends on both resolution and codec. In general: the optimal bitrate is actually proportional to the resolution. So the next question is: what kind of resolution steps make sense? Apparently, people need about a 2x increase in resolution to really see (and prefer) a marked difference. Anything less than that and many people will simply not bother with the higher bitrates, they’d rather use their bandwidth for other stuff. This has been researched quite a long time ago and is the big reason why we went from 720×576 (415kpix) to 1280×720 (922kpix), and then again from 1280×720 to 1920×1080 (2MP). Stuff in between is not a viable optimization target. And again, 1440P is about 3.7MP, another ~2x increase over HD. You will see a difference there. 4K is the next step after that. Next up is that magical number of 360 vertical pixels. Actually, the magic number is 120 or 128. All resolutions are some kind of multiple of 120 pixels nowadays, back in the day they used to be multiples of 128. This is something that just grew out of LCD panel industry. LCD panels use what are called line drivers, little chips that sit on the sides of your LCD screen that control how bright each subpixel is. Because historically, for reasons I don’t really know for sure, probably memory constraints, these multiple-of-128 or multiple-of-120 resolutions already existed, the industry standard line drivers became drivers with 360 line outputs (1 per subpixel). If you would tear down your 1920×1080 screen, I would be putting money on there being 16 line drivers on the top/bottom and 9 on one of the sides. Oh hey, that’s 16:9. Guess how obvious that resolution choice was back when 16:9 was ‘invented’. Then there’s the issue of aspect ratio. This is really a completely different field of psychology, but it boils down to: historically, people have believed and measured that we have a sort of wide-screen view of the world. Naturally, people believed that the most natural representation of data on a screen would be in a wide-screen view, and this is where the great anamorphic revolution of the ’60s came from when films were shot in ever wider aspect ratios. Since then, this kind of knowledge has been refined and mostly debunked. Yes, we do have a wide-angle view, but the area where we can actually see sharply – the center of our vision – is fairly round. Slightly elliptical and squashed, but not really more than about 4:3 or 3:2. So for detailed viewing, for instance for reading text on a screen, you can utilize most of your detail vision by employing an almost-square screen, a bit like the screens up to the mid-2000s. However, again this is not how marketing took it. Computers in ye olden days were used mostly for productivity and detailed work, but as they commoditized and as the computer as media consumption device evolved, people didn’t necessarily use their computer for work most of the time. They used it to watch media content: movies, television series and photos. And for that kind of viewing, you get the most ‘immersion factor’ if the screen fills as much of your vision (including your peripheral vision) as possible. Which means widescreen. But there’s more marketing still. When detail work was still an important factor, people cared about resolution. As many pixels as possible on the screen. SGI was selling almost-4K CRTs! The most optimal way to get the maximum amount of pixels out of a glass substrate is to cut it as square as possible. 1:1 or 4:3 screens have the most pixels per diagonal inch. But with displays becoming more consumery, inch-size became more important, not amount of pixels. And this is a completely different optimization target. To get the most diagonal inches out of a substrate, you want to make the screen as wide as possible. First we got 16:10, then 16:9 and there have been moderately successful panel manufacturers making 22:9 and 2:1 screens (like Philips). Even though pixel density and absolute resolution went down for a couple of years, inch-sizes went up and that’s what sold. Why buy a 19″ 1280×1024 when you can buy a 21″ 1366×768? Eh… I think that about covers all the major aspects here. There’s more of course; bandwidth limits of HDMI, DVI, DP and of course VGA played a role, and if you go back to the pre-2000s, graphics memory, in-computer bandwdith and simply the limits of commercially available RAMDACs played an important role. But for today’s considerations, this is about all you need to know. Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.     

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  • Ubuntu 12.04 + Wifi not working

    - by user171154
    i'm having problems connecting over wireless. At the moment, I'm using wicd. It seems to get stuck on "Verifying AP association...". Without wicd I can get the connection up and ping the Net - but if I take eth0 down (ifconfig eth0 down), my wireless goes away too (same result if I unplug the wire instead). wicd is the only way I can bring eth0 back (which is the main reason I'm using it) - ifconfig eth0 and/or ifup eth0 do not re-enable the connection (I just discovered it leaves out the gateway. Adding the gateway back in re-enables the connection including wifi; I didn't want to delete the info about wicd above in case it gives someone an idea.) Doing it manually, despite the errors (which it would be nice to also resolve) - allows me to ping the outside world: ifup wlan0 ioctl[SIOCSIWENCODEEXT]: Invalid argument ioctl[SIOCSIWENCODEEXT]: Invalid argument ssh stop/waiting ssh start/running, process 17336 ping -I wlan0 -c 4 8.8.8.8 PING 8.8.8.8 (8.8.8.8) from 192.168.0.12 wlan0: 56(84) bytes of data. 64 bytes from 8.8.8.8: icmp_req=1 ttl=43 time=48.8 ms 64 bytes from 8.8.8.8: icmp_req=2 ttl=43 time=47.9 ms 64 bytes from 8.8.8.8: icmp_req=3 ttl=43 time=48.7 ms 64 bytes from 8.8.8.8: icmp_req=4 ttl=43 time=53.2 ms --- 8.8.8.8 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 3003ms rtt min/avg/max/mdev = 47.975/49.711/53.235/2.063 ms # iwconfig lo no wireless extensions. wlan0 IEEE 802.11bgn ESSID:"TPLINK" Mode:Managed Frequency:2.427 GHz Access Point: 64:66:xx:xx:xx:22 Bit Rate=108 Mb/s Tx-Power=27 dBm Retry long limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:off Link Quality=70/70 Signal level=-39 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:3 Missed beacon:0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 01 serial: f0:7d:68:c1:b4:13 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=ath9k driverversion=3.2.0-67-generic-pae firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:17 memory:dfbf0000-dfbfffff ip route default via 192.168.0.1 dev eth0 default via 192.168.0.1 dev wlan0 metric 100 169.254.0.0/16 dev wlan0 scope link metric 1000 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.102 192.168.0.0/24 dev wlan0 proto kernel scope link src 192.168.0.12 (For the record, I have no idea what the 169.254.0.0 address is doing there.) uname -a 3.2.0-67-generic-pae #101-Ubuntu SMP Tue Jul 15 18:04:54 UTC 2014 i686 i686 i386 GNU/Linux lshw -C network *-network description: Ethernet interface product: NetXtreme BCM5751 Gigabit Ethernet PCI Express vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: 01 serial: 00:11:11:59:fc:09 size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.121 duplex=full firmware=5751-v3.23a ip=192.168.0.102 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s resources: irq:16 memory:dfcf0000-dfcfffff *-network description: Wireless interface product: AR5418 Wireless Network Adapter [AR5008E 802.11(a)bgn] (PCI-Express) vendor: Qualcomm Atheros physical id: 0 /etc/network/interfaces # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback source /etc/network/interfaces.eth0 source /etc/network/interfaces.wlan0 /etc/network/interfaces.eth0 #Main Interface auto eth0 iface eth0 inet static address 192.168.0.102 netmask 255.255.255.0 gateway 192.168.0.1 /etc/network/interfaces.wlan0 auto wlan0 iface wlan0 inet static address 192.168.0.12 gateway 192.168.0.1 dns-nameservers 192.168.0.1 8.8.8.8 netmask 255.255.255.0 wpa-driver wext wpa-ssid TPLINK wpa-ap-scan 1 wpa-proto RSN wpa-pairwise CCMP wpa-group CCMP wpa-key-mgmt WPA-PSK wpa-psk dca1badb5fd4e9axxx4xxdaaxxfa91xx610bxx6a7d57ef67af9809dxx6af42e39 /etc/wpa_supplicant.conf ctrl_interface=/var/run/wpa_supplicant network={ ssid="TPLINK" psk="my password" key_mgmt=WPA-PSK proto=RSN pairwise=CCMP group=CCMP } ifdown eth0 ifdown: interface eth0 not configured ifconfig eth0 Link encap:Ethernet HWaddr 00:11:xx:xx:xx:09 inet addr:192.168.0.102 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::211:11ff:fe59:fc09/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:213690 errors:0 dropped:0 overruns:0 frame:0 TX packets:155266 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:220057808 (220.0 MB) TX bytes:21137696 (21.1 MB) Interrupt:16 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:196412 errors:0 dropped:0 overruns:0 frame:0 TX packets:196412 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:153270697 (153.2 MB) TX bytes:153270697 (153.2 MB) wlan0 Link encap:Ethernet HWaddr f0:7d:xx:xx:xx:13 inet addr:192.168.0.12 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::f27d:68ff:fec1:b413/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:11335 errors:0 dropped:0 overruns:0 frame:0 TX packets:7287 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2563290 (2.5 MB) TX bytes:855746 (855.7 KB) ifconfig eth0 down ifconfig eth0 Link encap:Ethernet HWaddr 00:xx:xx:xx:xx:09 inet addr:192.168.0.102 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::211:11ff:fe59:fc09/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2 errors:0 dropped:0 overruns:0 frame:0 TX packets:1 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:192 (192.0 B) TX bytes:94 (94.0 B) Interrupt:16 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:196418 errors:0 dropped:0 overruns:0 frame:0 TX packets:196418 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:153270871 (153.2 MB) TX bytes:153270871 (153.2 MB) wlan0 Link encap:Ethernet HWaddr f0:7d:xx:xx:xx:13 inet addr:192.168.0.12 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::f27d:68ff:fec1:b413/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:11359 errors:0 dropped:0 overruns:0 frame:0 TX packets:7293 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2565482 (2.5 MB) TX bytes:856363 (856.3 KB) ip route default via 192.168.0.1 dev wlan0 metric 100 169.254.0.0/16 dev wlan0 scope link metric 1000 192.168.0.0/24 dev wlan0 proto kernel scope link src 192.168.0.12 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.102 ping -I wlan0 -c 4 8.8.8.8 PING 8.8.8.8 (8.8.8.8) from 192.168.0.12 wlan0: 56(84) bytes of data. --- 8.8.8.8 ping statistics --- 4 packets transmitted, 0 received, 100% packet loss, time 3024ms ping -I eth0 -c 3 router PING router (192.168.0.1) from 192.168.0.102 eth0: 56(84) bytes of data. --- router ping statistics --- 3 packets transmitted, 0 received, 100% packet loss, time 2015ms ping -I wlan0 -c 3 router PING router (192.168.0.1) from 192.168.0.12 wlan0: 56(84) bytes of data. --- router ping statistics --- 3 packets transmitted, 0 received, 100% packet loss, time 2014ms Let me know if you need more info. Thank you in advance.

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  • Wireless networks are not detected at start up in Ubuntu 12.04

    - by Kanhaiya Mishra
    I have recently (three four days ago) installed Ubuntu 12.04 via windows installer i.e. wubi.exe. After the installation completed wireless and Ethernet were both working well. But after restart wireless networks didn't show up while in the network manager both networking and wireless were enabled. Though sometimes after boot it did show the networks available but very rarely. So I went through various posts regarding wireless issues in Ubuntu 12.04 and tried so many things but ended up in nothing satisfactory. I have Broadcom 4313 LAN network controller and brcmsmac driver. Then relying on some suggestions I tried to install bcm-wl driver but couldn't install due to some error in jockeyl.log file. Then i tried fresh installation of the same driver but still could resolve the startup issues with wireless. Then again I reinstalled Ubuntu inside windows using wubi installer. This time again same problem occurred after boot. But this time I successfully installed wl driver before disturbing file-system files of Ubuntu. But again the same issue. This time I noticed some new things: If I inserted Ethernet/LAN cable before startup then wireless networks are available and of course LAN(wired) networks also work. but if i don't plug in cable before startup and then plug it after startup then it didn't detect Ethernet network neither wireless. So I haven't noticed it before that LAN along with wifi also doesn't work after startup. But if i suspend the session and make it sleep and again login then it worked. I tried it every time that WLAN worked perfectly. But still i m unable to resolve that startup problem. Each time i boot first I have to suspend it once then only networks are available. It irritates me each time i reboot/boot my lappy. So please help out of this problem. Any ideas/help regarding this issue would be highly appreciated. Some of the commands that i run gave following results: # lspci 00:00.0 Host bridge: Intel Corporation Core Processor DRAM Controller (rev 12) 00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 12) 00:16.0 Communication controller: Intel Corporation 5 Series/3400 Series Chipset HECI Controller (rev 06) 00:1a.0 USB controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 06) 00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 06) 00:1c.0 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 1 (rev 06) 00:1c.1 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 2 (rev 06) 00:1c.5 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 6 (rev 06) 00:1d.0 USB controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 06) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev a6) 00:1f.0 ISA bridge: Intel Corporation Mobile 5 Series Chipset LPC Interface Controller (rev 06) 00:1f.2 SATA controller: Intel Corporation 5 Series/3400 Series Chipset 6 port SATA AHCI Controller (rev 06) 00:1f.3 SMBus: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller (rev 06) 00:1f.6 Signal processing controller: Intel Corporation 5 Series/3400 Series Chipset Thermal Subsystem (rev 06) 03:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller (rev 01) 04:00.0 Ethernet controller: Atheros Communications Inc. AR8152 v1.1 Fast Ethernet (rev c1) ff:00.0 Host bridge: Intel Corporation Core Processor QuickPath Architecture Generic Non-core Registers (rev 02) ff:00.1 Host bridge: Intel Corporation Core Processor QuickPath Architecture System Address Decoder (rev 02) ff:02.0 Host bridge: Intel Corporation Core Processor QPI Link 0 (rev 02) ff:02.1 Host bridge: Intel Corporation Core Processor QPI Physical 0 (rev 02) ff:02.2 Host bridge: Intel Corporation Core Processor Reserved (rev 02) ff:02.3 Host bridge: Intel Corporation Core Processor Reserved (rev 02) # sudo lshw -C network *-network description: Wireless interface product: BCM4313 802.11b/g/n Wireless LAN Controller vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: eth1 version: 01 serial: 70:f1:a1:49:b6:ab width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=wl0 driverversion=5.100.82.38 ip=192.168.1.7 latency=0 multicast=yes wireless=IEEE 802.11 resources: irq:17 memory:f0500000-f0503fff *-network description: Ethernet interface product: AR8152 v1.1 Fast Ethernet vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:04:00.0 logical name: eth0 version: c1 serial: b8:ac:6f:6b:f7:4a capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI firmware=N/A latency=0 link=no multicast=yes port=twisted pair resources: irq:44 memory:f0400000-f043ffff ioport:2000(size=128) # lsmod | grep wl wl 2568210 0 lib80211 14381 2 lib80211_crypt_tkip,wl # sudo iwlist eth1 scanning eth1 Scan completed : Cell 01 - Address: 30:46:9A:85:DA:9A ESSID:"BH DASHIR 2" Mode:Managed Frequency:2.462 GHz (Channel 11) Quality:4/5 Signal level:-60 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK IE: Unknown: DD7F0050F204104A00011010440001021041000100103B000103104700109AFE7D908F8E2D381860668BA2E8D8771021000D4E4554474541522C20496E632E10230009574752363134763130102400095747523631347631301042000538333235381054000800060050F204000110110009574752363134763130100800020084 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s Cell 02 - Address: C0:3F:0E:EB:45:14 ESSID:"BH DASHIR 3" Mode:Managed Frequency:2.462 GHz (Channel 11) Quality:2/5 Signal level:-71 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK IE: Unknown: DD7F0050F204104A00011010440001021041000100103B00010310470010F3C9BBE499D140540F530E7EBEDE2F671021000D4E4554474541522C20496E632E10230009574752363134763130102400095747523631347631301042000538333235381054000800060050F204000110110009574752363134763130100800020084 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s Cell 03 - Address: A0:21:B7:A8:2F:C0 ESSID:"BH DASHIR 4" Mode:Managed Frequency:2.422 GHz (Channel 3) Quality:1/5 Signal level:-86 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK IE: Unknown: DD8B0050F204104A0001101044000102103B0001031047001000000000000010000000A021B7A82FC01021000D4E6574676561722C20496E632E10230009574E523130303076321024000456324831104200046E6F6E651054000800060050F20400011011001B574E5231303030763228576972656C6573732041502D322E344729100800020086103C000103 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s

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  • Oracle Certification and virtualization Solutions.

    - by scoter
    As stated in official MOS ( My Oracle Support ) document 249212.1 support for Oracle products on non-Oracle VM platforms follow exactly the same stance as support for VMware and, so, the only x86 virtualization software solution certified for any Oracle product is "Oracle VM". Based on the fact that: Oracle VM is totally free ( you have the option to buy Oracle-Support ) Certified is pretty different from supported ( OracleVM is certified, others could be supported ) With Oracle VM you may not require to reproduce your issue(s) on physical server Oracle VM is the only x86 software solution that allows hard-partitioning *** *** see details to these Oracle public links: http://www.oracle.com/technetwork/server-storage/vm/ovm-hardpart-168217.pdf http://www.oracle.com/us/corporate/pricing/partitioning-070609.pdf people started asking to migrate from third party virtualization software (ex. RH KVM, VMWare) to Oracle VM. Migrating RH KVM guest to Oracle VM. OracleVM has a built-in P2V utility ( Official Documentation ) but in some cases we can't use it, due to : network inaccessibility between hypervisors ( KVM and OVM ) network slowness between hypervisors (KVM and OVM) size of the guest virtual-disks Here you'll find a step-by-step guide to "manually" migrate a guest machine from KVM to OVM. 1. Verify source guest characteristics. Using KVM web console you can verify characteristics of the guest you need to migrate, such as: CPU Cores details Defined Memory ( RAM ) Name of your guest Guest operating system Disks details ( number and size ) Network details ( number of NICs and network configuration ) 2. Export your guest in OVF / OVA format.  The export from Redhat KVM ( kernel virtual machine ) will create a structured export of your guest: [root@ovmserver1 mnt]# lltotal 12drwxrwx--- 5 36 36 4096 Oct 19 2012 b8296fca-13c4-4841-a50f-773b5139fcee b8296fca-13c4-4841-a50f-773b5139fcee is the ID of the guest exported from RH-KVM [root@ovmserver1 mnt]# cd b8296fca-13c4-4841-a50f-773b5139fcee/[root@ovmserver1 b8296fca-13c4-4841-a50f-773b5139fcee]# ls -ltrtotal 12drwxr-x--- 4 36 36 4096 Oct 19  2012 masterdrwxrwx--- 2 36 36 4096 Oct 29  2012 dom_mddrwxrwx--- 4 36 36 4096 Oct 31  2012 images images contains your virtual-disks exported [root@ovmserver1 b8296fca-13c4-4841-a50f-773b5139fcee]# cd images/[root@ovmserver1 images]# ls -ltratotal 16drwxrwx--- 5 36 36 4096 Oct 19  2012 ..drwxrwx--- 2 36 36 4096 Oct 31  2012 d4ef928d-6dc6-4743-b20d-568b424728a5drwxrwx--- 2 36 36 4096 Oct 31  2012 4b241ea0-43aa-4f3b-ab7d-2fc633b491a1drwxrwx--- 4 36 36 4096 Oct 31  2012 .[root@ovmserver1 images]# cd d4ef928d-6dc6-4743-b20d-568b424728a5/[root@ovmserver1 d4ef928d-6dc6-4743-b20d-568b424728a5]# ls -ltotal 5169092-rwxr----- 1 36 36 187904819200 Oct 31  2012 4c03b1cf-67cc-4af0-ad1e-529fd665dac1-rw-rw---- 1 36 36          341 Oct 31  2012 4c03b1cf-67cc-4af0-ad1e-529fd665dac1.meta[root@ovmserver1 d4ef928d-6dc6-4743-b20d-568b424728a5]# file 4c03b1cf-67cc-4af0-ad1e-529fd665dac14c03b1cf-67cc-4af0-ad1e-529fd665dac1: LVM2 (Linux Logical Volume Manager) , UUID: sZL1Ttpy0vNqykaPahEo3hK3lGhwspv 4c03b1cf-67cc-4af0-ad1e-529fd665dac1 is the first exported disk ( physical volume ) [root@ovmserver1 d4ef928d-6dc6-4743-b20d-568b424728a5]# cd ../4b241ea0-43aa-4f3b-ab7d-2fc633b491a1/[root@ovmserver1 4b241ea0-43aa-4f3b-ab7d-2fc633b491a1]# ls -ltotal 5568076-rwxr----- 1 36 36 107374182400 Oct 31  2012 9020f2e1-7b8a-4641-8f80-749768cc237a-rw-rw---- 1 36 36          341 Oct 31  2012 9020f2e1-7b8a-4641-8f80-749768cc237a.meta[root@ovmserver1 4b241ea0-43aa-4f3b-ab7d-2fc633b491a1]# file 9020f2e1-7b8a-4641-8f80-749768cc237a9020f2e1-7b8a-4641-8f80-749768cc237a: x86 boot sector; partition 1: ID=0x83, active, starthead 1, startsector 63, 401562 sectors; partition 2: ID=0x82, starthead 0, startsector 401625, 65529135 sectors; startsector 63, 401562 sectors; partition 2: ID=0x82, starthead 0, startsector 401625, 65529135 sectors; partition 3: ID=0x83, starthead 254, startsector 65930760, 8385930 sectors; partition 4: ID=0x5, starthead 254, startsector 74316690, 135395820 sectors, code offset 0x48 9020f2e1-7b8a-4641-8f80-749768cc237a is the second exported disk, with partition 1 bootable 3. Prepare the new guest on Oracle VM. By Ovm-Manager we can prepare the guest where we will move the exported virtual-disks; under the Tab "Servers and VMs": click on  and create your guest with parameters collected before (point 1): - add NICs on different networks: - add virtual-disks; in this case we add two disks of 1.0 GB each one; we will extend the virtual disk copying the source KVM virtual-disk ( see next steps ) - verify virtual-disks created ( under Repositories tab ) 4. Verify OVM virtual-disks names. [root@ovmserver1 VirtualMachines]# grep -r hyptest_rdbms * 0004fb0000060000a906b423f44da98e/vm.cfg:OVM_simple_name = 'hyptest_rdbms' [root@ovmserver1 VirtualMachines]# cd 0004fb0000060000a906b423f44da98e [root@ovmserver1 0004fb0000060000a906b423f44da98e]# more vm.cfgvif = ['mac=00:21:f6:0f:3f:85,bridge=0004fb001089128', 'mac=00:21:f6:0f:3f:8e,bridge=0004fb00101971d'] OVM_simple_name = 'hyptest_rdbms' vnclisten = '127.0.0.1' disk = ['file:/OVS/Repositories/0004fb00000300004f17b7368139eb41/ VirtualDisks/0004fb000012000097c1bfea9834b17d.img,xvda,w', 'file:/OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb0000120000cde6a11c3cb1d0be.img,xvdb,w'] vncunused = '1' uuid = '0004fb00-0006-0000-a906-b423f44da98e' on_reboot = 'restart' cpu_weight = 27500 memory = 32768 cpu_cap = 0 maxvcpus = 8 OVM_high_availability = True maxmem = 32768 vnc = '1' OVM_description = '' on_poweroff = 'destroy' on_crash = 'restart' name = '0004fb0000060000a906b423f44da98e' guest_os_type = 'linux' builder = 'hvm' vcpus = 8 keymap = 'en-us' OVM_os_type = 'Oracle Linux 5' OVM_cpu_compat_group = '' OVM_domain_type = 'xen_hvm' disk2 ovm ==> /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb0000120000cde6a11c3cb1d0be.img disk1 ovm ==> /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb000012000097c1bfea9834b17d.img Summarizing disk1 --source ==> /mnt/b8296fca-13c4-4841-a50f-773b5139fcee/images/4b241ea0-43aa-4f3b-ab7d-2fc633b491a1/9020f2e1-7b8a-4641-8f80-749768cc237a disk1 --dest ==> /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb000012000097c1bfea9834b17d.img disk2 --source ==> /mnt/b8296fca-13c4-4841-a50f-773b5139fcee/images/d4ef928d-6dc6-4743-b20d-568b424728a5/4c03b1cf-67cc-4af0-ad1e-529fd665dac1 disk2 --dest ==> /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb0000120000cde6a11c3cb1d0be.img 5. Copy KVM exported virtual-disks to OVM virtual-disks. Keeping your Oracle VM guest stopped you can copy KVM exported virtual-disks to OVM virtual-disks; what I did is only to locally mount the filesystem containing the exported virtual-disk ( by an usb device ) on my OVS; the copy automatically resize OVM virtual-disks ( previously created with a size of 1GB ) . nohup cp /mnt/b8296fca-13c4-4841-a50f-773b5139fcee/images/4b241ea0-43aa-4f3b-ab7d-2fc633b491a1/9020f2e1-7b8a-4641-8f80-749768cc237a /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/0004fb000012000097c1bfea9834b17d.img & nohup cp /mnt/b8296fca-13c4-4841-a50f-773b5139fcee/images/d4ef928d-6dc6-4743-b20d-568b424728a5/4c03b1cf-67cc-4af0-ad1e-529fd665dac1 /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/0004fb0000120000cde6a11c3cb1d0be.img & 7. When copy completed refresh repository to aknowledge the new-disks size. 7. After "refresh repository" is completed, start guest machine by Oracle VM manager. After the first start of your guest: - verify that you can see all disks and partitions - verify that your guest is network reachable ( MAC Address of your NICs changed ) Eventually you can also evaluate to convert your guest to PVM ( Paravirtualized virtual Machine ) following official Oracle documentation. Ciao Simon COTER ps: next-time I'd like to post an article reporting how to manually migrate Virtual-Iron guests to OracleVM.  Comments and corrections are welcome. 

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  • ATI propriatery drivers install latest 12.8, broke my kernel. Stuck on kernel 3.2.0-26

    - by user66987
    I messed up a bit. Hoping some here can help me. I tried to install the newest catalyst 12.8. Sadly, this broke my system. I was stuck in low graphics mode. I finally managed to restore the proprietary drivers, and get into ubuntu again. But now I am stuck on kernel 3.2.0.26. I had installed kernel 3.2.0-30, but the system no longer sees it. I have kernel 3.2.0-29 too, but the system cannot see that as well. In the grub menu. When I use sudo update-grub, they are both listed. Here are the output I get: Searching for GRUB installation directory ... found: /boot/grub Cannot determine root device. Assuming /dev/hda1 This error is probably caused by an invalid /etc/fstab Searching for default file ... found: /boot/grub/default Testing for an existing GRUB menu.lst file ... found: /boot/grub/menu.lst Searching for splash image ... none found, skipping ... Found kernel: /boot/vmlinuz-3.2.0-30-generic Found kernel: /boot/vmlinuz-3.2.0-29-generic Found kernel: /boot/vmlinuz-3.2.0-27-generic Found kernel: /boot/vmlinuz-3.2.0-26-generic Found GRUB 2: /boot/grub/core.img Found kernel: /boot/memtest86+.bin Updating /boot/grub/menu.lst ... done I have searched everywhere to find a solution to my problem, but can't find any solutions. If you need any log outputs to figure out the problem, please let me know which ones. Update: here is the output for grub.cfg # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b set locale_dir=($root)/boot/grub/locale set lang=nb_NO insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${recordfail}" != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "${linux_gfx_mode}" != "text" ]; then load_video; fi menuentry 'Ubuntu, med Linux 3.2.0-26-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux /boot/vmlinuz-3.2.0-26-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-26-generic } menuentry 'Ubuntu, med Linux 3.2.0-26-generic (gjenopprettelsesmodus)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b echo 'Laster Linux 3.2.0-26-generic ...' linux /boot/vmlinuz-3.2.0-26-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-26-generic } submenu "Previous Linux versions" { menuentry 'Ubuntu, med Linux 3.2.0-25-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux /boot/vmlinuz-3.2.0-25-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-25-generic } menuentry 'Ubuntu, med Linux 3.2.0-25-generic (gjenopprettelsesmodus)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b echo 'Laster Linux 3.2.0-25-generic ...' linux /boot/vmlinuz-3.2.0-25-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-25-generic } menuentry 'Ubuntu, med Linux 3.2.0-24-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux /boot/vmlinuz-3.2.0-24-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-24-generic } menuentry 'Ubuntu, med Linux 3.2.0-24-generic (gjenopprettelsesmodus)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b echo 'Laster Linux 3.2.0-24-generic ...' linux /boot/vmlinuz-3.2.0-24-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-24-generic } menuentry 'Ubuntu, med Linux 3.2.0-23-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux /boot/vmlinuz-3.2.0-23-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-23-generic } menuentry 'Ubuntu, med Linux 3.2.0-23-generic (gjenopprettelsesmodus)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b echo 'Laster Linux 3.2.0-23-generic ...' linux /boot/vmlinuz-3.2.0-23-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-23-generic } } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sdb1)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd1,msdos1)' search --no-floppy --fs-uuid --set=root 448AF3CE8AF3BA8E chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### How can I set kernel 3.2.0.30 as the default kernel? According to this file, kernel 3.2.0-30 does not exist.

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  • Oracle Support Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1)

    - by faye.todd(at)oracle.com
    Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1) Copyright (c) 2010, Oracle Corporation. All Rights Reserved. In this Document  Purpose  Last Review Date  Instructions for the Reader  Troubleshooting Details     1. Scope and Application      2. Definitions and Classifications     3. How to Use This Guide     4. Basic AQ Propagation Troubleshooting     5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages     6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment     7. Performance Issues  References Applies to: Oracle Server - Enterprise Edition - Version: 8.1.7.0 to 11.2.0.2 - Release: 8.1.7 to 11.2Information in this document applies to any platform. Purpose This document presents a step-by-step methodology for troubleshooting and resolving problems with Advanced Queuing Propagation in both Streams and basic Advanced Queuing environments. It also serves as a master reference for other more specific notes on Oracle Streams Propagation and Advanced Queuing Propagation issues. Last Review Date December 20, 2010 Instructions for the Reader A Troubleshooting Guide is provided to assist in debugging a specific issue. When possible, diagnostic tools are included in the document to assist in troubleshooting. Troubleshooting Details 1. Scope and Application This note is intended for Database Administrators of Oracle databases where issues are being encountered with propagating messages between advanced queues, whether the queues are used for user-created messaging systems or for Oracle Streams. It contains troubleshooting steps and links to notes for further problem resolution.It can also be used a template to document a problem when it is necessary to engage Oracle Support Services. Knowing what is NOT happening can frequently speed up the resolution process by focusing solely on the pertinent problem area. This guide is divided into five parts: Section 2: Definitions and Classifications (discusses the different types and features of propagations possible - helpful for understanding the rest of the guide) Section 3: How to Use this Guide (to be used as a start part for determining the scope of the problem and what sections to consult) Section 4. Basic AQ propagation troubleshooting (applies to both AQ propagation of user enqueued and dequeued messages as well as Oracle Streams propagations) Section 5. Additional troubleshooting steps for AQ propagation of user enqueued and dequeued messages Section 6. Additional troubleshooting steps for Oracle Streams propagation Section 7. Performance issues 2. Definitions and Classifications Given the potential scope of issues that can be encountered with AQ propagation, the first recommended step is to do some basic diagnosis to determine the type of problem that is being encountered. 2.1. What Type of Propagation is Being Used? 2.1.1. Buffered Messaging For an advanced queue, messages can be maintained on disk (persistent messaging) or in memory (buffered messaging). To determine if a queue is buffered or not, reference the GV_$BUFFERED_QUEUES view. If the queue does not appear in this view, it is persistent. 2.1.2. Propagation mode - queue-to-dblink vs queue-to-queue As of 10.2, an AQ propagation can also be defined as queue-to-dblink, or queue-to-queue: queue-to-dblink: The propagation delivers messages or events from the source queue to all subscribing queues at the destination database identified by the dblink. A single propagation schedule is used to propagate messages to all subscribing queues. Hence any changes made to this schedule will affect message delivery to all the subscribing queues. This mode does not support multiple propagations from the same source queue to the same target database. queue-to-queue: Added in 10.2, this propagation mode delivers messages or events from the source queue to a specific destination queue identified on the database link. This allows the user to have fine-grained control on the propagation schedule for message delivery. This new propagation mode also supports transparent failover when propagating to a destination Oracle RAC system. With queue-to-queue propagation, you are no longer required to re-point a database link if the owner instance of the queue fails on Oracle RAC. This mode supports multiple propagations to the same target database if the target queues are different. The default is queue-to-dblink. To verify if queue-to-queue propagation is being used, in non-Streams environments query DBA_QUEUE_SCHEDULES.DESTINATION - if a remote queue is listed along with the remote database link, then queue-to-queue propagation is being used. For Streams environments, the DBA_PROPAGATION.QUEUE_TO_QUEUE column can be checked.See the following note for a method to switch between the two modes:Document 827473.1 How to alter propagation from queue-to-queue to queue-to-dblink 2.1.3. Combined Capture and Apply (CCA) for Streams In 11g Oracle Streams environments, an optimization called Combined Capture and Apply (CCA) is implemented by default when possible. Although a propagation is configured in this case, Streams does not use it; instead it passes information directly from capture to an apply receiver. To see if CCA is in use: COLUMN CAPTURE_NAME HEADING 'Capture Name' FORMAT A30COLUMN OPTIMIZATION HEADING 'CCA Mode?' FORMAT A10SELECT CAPTURE_NAME, DECODE(OPTIMIZATION,0, 'No','Yes') OPTIMIZATIONFROM V$STREAMS_CAPTURE; Also, see the following note:Document 463820.1 Streams Combined Capture and Apply in 11g 2.2. Queue Table Compatibility There are three types of queue table compatibility. In more recent databases, queue tables may be present in all three modes of compatibility: 8.0 - earliest version, deprecated in 10.2 onwards 8.1 - support added for RAC, asynchronous notification, secure queues, queue level access control, rule-based subscribers, separate storage of history information 10.0 - if the database is in 10.1-compatible mode, then the default value for queue table compatibility is 10.0 2.3. Single vs Multiple Consumer Queue Tables If more than one recipient can dequeue a message from a queue, then its queue table is multiple consumer. You can propagate messages from a multiple-consumer queue to a single-consumer queue. Propagation from a single-consumer queue to a multiple-consumer queue is not possible. 3. How to Use This Guide 3.1. Are Messages Being Propagated at All, or is the Propagation Just Slow? Run the following query on the source database for the propagation (assuming that it is running): select TOTAL_NUMBER from DBA_QUEUE_SCHEDULES where QNAME='<source_queue_name>'; If TOTAL_NUMBER is increasing, then propagation is most likely functioning, although it may be slow. For performance issues, see Section 7. 3.2. Propagation Between Persistent User-Created Queues See Sections 4 and 5 (and optionally Section 6 if performance is an issue). 3.3. Propagation Between Buffered User-Created Queues See Sections 4, 5, and 6 (and optionally Section 7 if performance is an issue). 3.4. Propagation between Oracle Streams Queues (without Combined Capture and Apply (CCA) Optimization) See Sections 4 and 6 (and optionally Section 7 if performance is an issue). 3.5. Propagation between Oracle Streams Queues (with Combined Capture and Apply (CCA) Optimization) Although an AQ propagation is not used directly in this case, some characteristics of the message transfer are inferred from the propagation parameters used. Some parts of Sections 4 and 6 still apply. 3.6. Messaging Gateway Propagations This note does not apply to Messaging Gateway propagations. 4. Basic AQ Propagation Troubleshooting 4.1. Double-check Your Code Make sure that you are consistent in your usage of the database link(s) names, queue names, etc. It may be useful to plot a diagram of which queues are connected via which database links to make sure that the logical structure is correct. 4.2. Verify that Job Queue Processes are Running 4.2.1. Versions 10.2 and Lower - DBA_JOBS Package For versions 10.2 and lower, a scheduled propagation is managed by DBMS_JOB package. The propagation is performed by job queue process background processes. Therefore we need to verify that there are sufficient processes available for the propagation process. We should have at least 4 job queue processes running and preferably more depending on the number of other jobs running in the database. It should be noted that for AQ specific work, AQ will only ever use half of the job queue processes available.An issue caused by an inadequate job queue processes parameter setting is described in the following note:Document 298015.1 Kwqjswproc:Excep After Loop: Assigning To Self 4.2.1.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; 4.2.1.2. Job Queue Processes in Memory The following command will show how many job queue processes are currentlyin use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.1.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (spids) of job queue processes involved in propagation via select p.SPID, p.PROGRAM from V$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOBand j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%'; and these SPIDs can be used to check at the operating system level that they exist.In 8i a job queue process will have a name similar to: ora_snp1_<instance_name>.In 9i onwards you will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.2.2. Version 11.1 and Above - Oracle Scheduler In version 11.1 and above, Oracle Scheduler is used to perform AQ and Streams propagations. Oracle Scheduler automatically tunes the number of slave processes for these jobs based on the load on the computer system, and the JOB_QUEUE_PROCESSES initialization parameter is only used to specify the maximum number of slave processes. Therefore, the JOB_QUEUE_PROCESSES initialization parameter does not need to be set (it defaults to a very high number), unless you want to limit the number of slaves that can be created. If JOB_QUEUE_PROCESSES = 0, no propagation jobs will run.See the following note for a discussion of Oracle Streams 11g and Oracle Scheduler:Document 1083608.1 11g Streams and Oracle Scheduler 4.2.2.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0, and preferably be left at its default value. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; To set the JOB_QUEUE_PROCESSES parameter to its default value, run: connect / as sysdbaalter system reset JOB_QUEUE_PROCESSES; and then bounce the instance. 4.2.2.2. Job Queue Processes in Memory The following command will show how many job queue processes are currently in use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.2.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (SPIDs) of job queue processes involved in propagation via col PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_namefrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDRand jr.JOB_name=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%'; and these SPIDs can be used to check at the operating system level that they exist.You will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.3. Check the Alert Log and Any Associated Trace Files The first place to check for propagation failures is the alert logs at all sites (local and if relevant all remote sites). When a job queue process attempts to execute a schedule and fails it will always write an error stack to the alert log. This error stack will also be written in a job queue process trace file, which will be written to the BACKGROUND_DUMP_DEST location for 10.2 and below, and in the DIAGNOSTIC_DEST location for 11g. The fact that errors are written to the alert log demonstrates that the schedule is executing. This means that the problem could be with the set up of the schedule. In this example the ORA-02068 demonstrates that the failure was at the remote site. Further investigation revealed that the remote database was not open, hence the ORA-03114 error. Starting the database resolved the problem. Thu Feb 14 10:40:05 2002 Propagation Schedule for (AQADM.MULTIPLEQ, SHANE816.WORLD) encountered following error:ORA-04052: error occurred when looking up Remote object [email protected]: error occurred at recursive SQL level 4ORA-02068: following severe error from SHANE816ORA-03114: not connected to ORACLEORA-06512: at "SYS.DBMS_AQADM_SYS", line 4770ORA-06512: at "SYS.DBMS_AQADM", line 548ORA-06512: at line 1 Other potential errors that may be written to the alert log can be found in the following notes:Document 827184.1 AQ Propagation with CLOB data types Fails with ORA-22990 (11.1)Document 846297.1 AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn] (10.2, 11.1)Document 731292.1 ORA-25215 Reported on Local Propagation When Using Transformation with ANYDATA queue tables (10.2, 11.1, 11.2)Document 365093.1 ORA-07445 [kwqppay2aqe()+7360] Reported on Propagation of a Transformed Message (10.1, 10.2)Document 219416.1 Advanced Queuing Propagation Fails with ORA-22922 (9.0)Document 1203544.1 AQ Propagation Aborted with ORA-600 [ociksin: invalid status] on SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE After Upgrade (11.1, 11.2)Document 1087324.1 ORA-01405 ORA-01422 reported by Advanced Queuing Propagation schedules after RAC reconfiguration (10.2)Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370 incorrect usage of method" (9.2, 10.2, 11.1, 11.2)Document 332792.1 ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up Statspack (8.1, 9.0, 9.2, 10.1)Document 353325.1 ORA-24056: Internal inconsistency for QUEUE <queue_name> and destination <dblink> (8.1, 9.0, 9.2, 10.1, 10.2, 11.1, 11.2)Document 787367.1 ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2 (10.1, 10.2)Document 566622.1 ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1 (9.2, 10.1)Document 731539.1 ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTP (9.0, 9.2, 10.1, 10.2, 11.1)Document 253131.1 Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555) (9.2)Document 118884.1 How to unschedule a propagation schedule stuck in pending stateDocument 222992.1 DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 1204080.1 AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.Document 1233675.1 AQ Propagation stops after upgrade to 11.2.0.1 ORA-30757 4.3.1. Errors Related to Incorrect Network Configuration The most common propagation errors result from an incorrect network configuration. The list below contains common errors caused by tnsnames.ora file or database links being configured incorrectly: - ORA-12154: TNS:could not resolve service name- ORA-12505: TNS:listener does not currently know of SID given in connect descriptor- ORA-12514: TNS:listener could not resolve SERVICE_NAME - ORA-12541: TNS-12541 TNS:no listener 4.4. Check the Database Links Exist and are Functioning Correctly For schedules to remote databases confirm the database link exists via. SQL> col DBLINK for a45SQL> select QNAME, NVL(REGEXP_SUBSTR(DESTINATION, '[^@]+', 1, 2), DESTINATION) dblink2 from DBA_QUEUE_SCHEDULES3 where MESSAGE_DELIVERY_MODE = 'PERSISTENT';QNAME DBLINK------------------------------ ---------------------------------------------MY_QUEUE ORCL102B.WORLD Connect as the owner of the link and select across it to verify it works and connects to the database we expect. i.e. select * from ALL_QUEUES@ ORCL102B.WORLD; You need to ensure that the userid that scheduled the propagation (using DBMS_AQADM.SCHEDULE_PROPAGATION or DBMS_PROPAGATION_ADM.CREATE_PROPAGATION if using Streams) has access to the database link for the destination. 4.5. Has Propagation Been Correctly Scheduled? Check that the propagation schedule has been created and that a job queue process has been assigned. Look for the entry in DBA_QUEUE_SCHEDULES and SYS.AQ$_SCHEDULES for your schedule. For 10g and below, check that it has a JOBNO entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_JOBS with that JOBNO. For 11g and above, check that the schedule has a JOB_NAME entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_SCHEDULER_JOBS with that JOB_NAME. Check the destination is as intended and spelled correctly. SQL> select SCHEMA, QNAME, DESTINATION, SCHEDULE_DISABLED, PROCESS_NAME from DBA_QUEUE_SCHEDULES;SCHEMA QNAME DESTINATION S PROCESS------- ---------- ------------------ - -----------AQADM MULTIPLEQ AQ$_LOCAL N J000 AQ$_LOCAL in the destination column shows that the queue to which we are propagating to is in the same database as the source queue. If the propagation was to a remote (different) database, a database link will be in the DESTINATION column. The entry in the SCHEDULE_DISABLED column, N, means that the schedule is NOT disabled. If Y (yes) appears in this column, propagation is disabled and the schedule will not be executed. If not using Oracle Streams, propagation should resume once you have enabled the schedule by invoking DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE (for 10.2 Oracle Streams and above, the DBMS_PROPAGATION_ADM.START_PROPAGATION procedure should be used). The PROCESS_NAME is the name of the job queue process currently allocated to execute the schedule. This process is allocated dynamically at execution time. If the PROCESS_NAME column is null (empty) the schedule is not currently executing. You may need to execute this statement a number of times to verify if a process is being allocated. If a process is at some time allocated to the schedule, it is attempting to execute. SQL> select SCHEMA, QNAME, LAST_RUN_DATE, NEXT_RUN_DATE from DBA_QUEUE_SCHEDULES;SCHEMA QNAME LAST_RUN_DATE NEXT_RUN_DATE------ ----- ----------------------- ----------------------- AQADM MULTIPLEQ 13-FEB-2002 13:18:57 13-FEB-2002 13:20:30 In 11g, these dates are expressed in TIMESTAMP WITH TIME ZONE datatypes. If the NEXT_RUN_DATE and NEXT_RUN_TIME columns are null when this statement is executed, the scheduled propagation is currently in progress. If they never change it would suggest that the schedule itself is never executing. If the next scheduled execution is too far away, change the NEXT_TIME parameter of the schedule so that schedules are executed more frequently (assuming that the window is not set to be infinite). Parameters of a schedule can be changed using the DBMS_AQADM.ALTER_PROPAGATION_SCHEDULE call. In 10g and below, scheduling propagation posts a job in the DBA_JOBS view. The columns are more or less the same as DBA_QUEUE_SCHEDULES so you just need to recognize the job and verify that it exists. SQL> select JOB, WHAT from DBA_JOBS where WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';JOB WHAT---- ----------------- 720 next_date := sys.dbms_aqadm.aq$_propaq(job); For 11g, scheduling propagation posts a job in DBA_SCHEDULER_JOBS instead: SQL> select JOB_NAME from DBA_SCHEDULER_JOBS where JOB_NAME like 'AQ_JOB$_%';JOB_NAME------------------------------AQ_JOB$_41 If no job exists, check DBA_QUEUE_SCHEDULES to make sure that the schedule has not been disabled. For 10g and below, the job number is dynamic for AQ propagation schedules. The procedure that is executed to expedite a propagation schedule runs, removes itself from DBA_JOBS, and then reposts a new job for the next scheduled propagation. The job number should therefore always increment unless the schedule has been set up to run indefinitely. 4.6. Is the Schedule Executing but Failing to Complete? Run the following query: SQL> select FAILURES, LAST_ERROR_MSG from DBA_QUEUE_SCHEDULES;FAILURES LAST_ERROR_MSG------------ -----------------------1 ORA-25207: enqueue failed, queue AQADM.INQ is disabled from enqueueingORA-02063: preceding line from SHANE816 The failures column shows how many times we have attempted to execute the schedule and failed. Oracle will attempt to execute the schedule 16 times after which it will be removed from the DBA_JOBS or DBA_SCHEDULER_JOBS view and the schedule will become disabled. The column DBA_QUEUE_SCHEDULES.SCHEDULE_DISABLED will show 'Y'. For 11g and above, the DBA_SCHEDULER_JOBS.STATE column will show 'BROKEN' for the job corresponding to DBA_QUEUE_SCHEDULES.JOB_NAME. Prior to 10g the back off algorithm for failures was exponential, whereas from 10g onwards it is linear. The propagation will become disabled on the 17th attempt. Only the last execution failure will be reflected in the LAST_ERROR_MSG column. That is, if the schedule fails 5 times for 5 different reasons, only the last set of errors will be recorded in DBA_QUEUE_SCHEDULES. Any errors need to be resolved to allow propagation to continue. If propagation has also become disabled due to 17 failures, first resolve the reason for the error and then re-enable the schedule using the DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE procedure, or DBMS_PROPAGATION_ADM.START_PROPAGATION if using 10.2 or above Oracle Streams. As soon as the schedule executes successfully the error message entries will be deleted. Oracle does not keep a history of past failures. However, when using Oracle Streams, the errors will be retained in the DBA_PROPAGATION view even after the schedule resumes successfully. See the following note for instructions on how to clear out the errors from the DBA_PROPAGATION view:Document 808136.1 How to clear the old errors from DBA_PROPAGATION view?If a schedule is active and no errors are being reported then the source queue may not have any messages to be propagated. 4.7. Do the Propagation Notification Queue Table and Queue Exist? Check to see that the propagation notification queue table and queue exist and are enabled for enqueue and dequeue. Propagation makes use of the propagation notification queue for handling propagation run-time events, and the messages in this queue are stored in a SYS-owned queue table. This queue should never be stopped or dropped and the corresponding queue table never be dropped. 10g and belowThe propagation notification queue table is of the format SYS.AQ$_PROP_TABLE_n, where 'n' is the RAC instance number, i.e. '1' for a non-RAC environment. This queue and queue table are created implicitly when propagation is first scheduled. If propagation has been scheduled and these objects do not exist, try unscheduling and rescheduling propagation. If they still do not exist contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ$_PROP_TABLE_1SQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ$_PROP_NOTIFY_1 YES YESAQ$_AQ$_PROP_TABLE_1_E NO NO If the AQ$_PROP_NOTIFY_1 queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_1_E should not be enabled for enqueue or dequeue.11g and aboveThe propagation notification queue table is of the format SYS.AQ_PROP_TABLE, and is created when the database is created. If they do not exist, contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ_PROP_TABLESQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ_PROP_NOTIFY YES YESAQ$_AQ_PROP_TABLE_E NO NO If the AQ_PROP_NOTIFY queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_E should not be enabled for enqueue or dequeue. 4.8. Does the Remote Queue Exist and is it Enabled for Enqueueing? Check that the remote queue the propagation is transferring messages to exists and is enabled for enqueue: SQL> select DESTINATION from USER_QUEUE_SCHEDULES where QNAME = 'OUTQ';DESTINATION-----------------------------------------------------------------------------"AQADM"."INQ"@M2V102.ESSQL> select OWNER, NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED from [email protected];OWNER NAME ENQUEUE DEQUEUE-------- ------ ----------- -----------AQADM INQ YES YES 4.9. Do the Target and Source Database Charactersets Differ? If a message fails to propagate, check the database charactersets of the source and target databases. Investigate whether the same message can propagate between the databases with the same characterset or it is only a particular combination of charactersets which causes a problem. 4.10. Check the Queue Table Type Agreement Propagation is not possible between queue tables which have types that differ in some respect. One way to determine if this is the case is to run the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure for the two queues that the propagation operates on. If the types do not agree, DBMS_AQADM.VERIFY_QUEUE_TYPES will return '0'.For AQ propagation between databases which have different NLS_LENGTH_SEMANTICS settings, propagation will not work, unless the queues are Oracle Streams ANYDATA queues.See the following notes for issues caused by lack of type agreement:Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 353754.1 Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT 4.11. Enable Propagation Tracing 4.11.1. System Level This is set it in the init.ora/spfile as follows: event="24040 trace name context forever, level 10" and restart the instanceThis event cannot be set dynamically with an alter system command until version 10.2: SQL> alter system set events '24040 trace name context forever, level 10'; To unset the event: SQL> alter system set events '24040 trace name context off'; Debugging information will be logged to job queue trace file(s) (jnnn) as propagation takes place. You can check the trace file for errors, and for statements indicating that messages have been sent. For the most part the trace information is understandable. This trace should also be uploaded to Oracle Support if a service request is created. 4.11.2. Attaching to a Specific Process We can also attach to an existing job queue processes that is running a propagation schedule and trace it individually using the oradebug utility, as follows:10.2 and below connect / as sysdbaselect p.SPID, p.PROGRAM from v$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 11g connect / as sysdbacol PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_NAMEfrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 4.11.3. Further Tracing The previous tracing steps only trace the job queue process executing the propagation on the source. At times it is useful to trace the propagation receiver process (the session which is enqueueing the messages into the target queue) on the target database which is associated with the job queue process on the source database.These following queries provide ways of identifying the processes involved in propagation so that you can attach to them via oradebug to generate trace information.In order to identify the propagation receiver process you need to execute the query as a user with privileges to access the v$ views in both the local and remote databases so the database link must connect as a user with those privileges in the remote database. The <DBLINK> in the queries should be replaced by the appropriate database link.The queries have two forms due to the differences between operating systems. The value returned by 'Rem Process' is the operating system identifier of the propagation receiver on the remote database. Once identified, this process can be attached to and traced on the remote database using the commands given in Section 4.11.2.10.2 and below - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from v$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 10.2 and below - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=sr.PROCESS; 11g - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 11g - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=sr.PROCESS;   5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages 5.1. Check the Privileges of All Users Involved Ensure that the owner of the database link has the necessary privileges on the aq packages. SQL> select TABLE_NAME, PRIVILEGE from USER_TAB_PRIVS;TABLE_NAME PRIVILEGE------------------------------ ----------------------------------------DBMS_LOCK EXECUTEDBMS_AQ EXECUTEDBMS_AQADM EXECUTEDBMS_AQ_BQVIEW EXECUTEQT52814_BUFFER SELECT Note that when queue table is created, a view called QT<nnn>_BUFFER is created in the SYS schema, and the queue table owner is given SELECT privileges on it. The <nnn> corresponds to the object_id of the associated queue table. SQL> select * from USER_ROLE_PRIVS;USERNAME GRANTED_ROLE ADM DEF OS_------------------------------ ------------------------------ ---- ---- ---AQ_USER1 AQ_ADMINISTRATOR_ROLE NO YES NOAQ_USER1 CONNECT NO YES NOAQ_USER1 RESOURCE NO YES NO It is good practice to configure central AQ administrative user. All admin and processing jobs are created, executed and administered as this user. This configuration is not mandatory however, and the database link can be owned by any existing queue user. If this latter configuration is used, ensure that the connecting user has the necessary privileges on the AQ packages and objects involved. Privileges for an AQ Administrative user Execute on DBMS_AQADM Execute on DBMS_AQ Granted the AQ_ADMINISTRATOR_ROLE Privileges for an AQ user Execute on DBMS_AQ Execute on the message payload Enqueue privileges on the remote queue Dequeue privileges on the originating queue Privileges need to be confirmed on both sites when propagation is scheduled to remote destinations. Verify that the user ID used to login to the destination through the database link has been granted privileges to use AQ. 5.2. Verify Queue Payload Types AQ will not propagate messages from one queue to another if the payload types of the two queues are not verified to be equivalent. An AQ administrator can verify if the source and destination's payload types match by executing the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure. The results of the type checking will be stored in the SYS.AQ$_MESSAGE_TYPES table. This table can be accessed using the object identifier OID of the source queue and the address database link of the destination queue, i.e. [schema.]queue_name[@destination]. Prior to Oracle 9i the payload (message type) had to be the same for all the queue tables involved in propagation. From Oracle9i onwards a transformation can be used so that payloads can be converted from one type to another. The following procedural call made on the source database can verify whether we can propagate between the source and the destination queue tables. connect aq_user1/[email protected] serverout onDECLARErc_value number;BEGINDBMS_AQADM.VERIFY_QUEUE_TYPES(src_queue_name => 'AQ_USER1.Q_1', dest_queue_name => 'AQ_USER2.Q_2',destination => 'dbl_aq_user2.es',rc => rc_value);dbms_output.put_line('rc_value code is '||rc_value);END;/ If propagation is possible then the return code value will be 1. If it is 0 then propagation is not possible and further investigation of the types and transformations used by and in conjunction with the queue tables is required. With regard to comparison of the types the following sql can be used to extract the DDL for a specific type with' %' changed appropriately on the source and target. This can then be compared for the source and target. SET LONG 20000 set pagesize 50 EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'STORAGE',false); SELECT DBMS_METADATA.GET_DDL('TYPE',t.type_name) from user_types t WHERE t.type_name like '%'; EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'DEFAULT'); 5.3. Check Message State and Destination The first step in this process is to identify the queue table associated with the problem source queue. Although you schedule propagation for a specific queue, most of the meta-data associated with that queue is stored in the underlying queue table. The following statement finds the queue table for a given queue (note that this is a multiple-consumer queue table). SQL> select QUEUE_TABLE from DBA_QUEUES where NAME = 'MULTIPLEQ';QUEUE_TABLE --------------------MULTIPLEQTABLE For a small amount of messages in a multiple-consumer queue table, the following query can be run: SQL> select MSG_STATE, CONSUMER_NAME, ADDRESS from AQ$MULTIPLEQTABLE where QUEUE = 'MULTIPLEQ';MSG_STATE CONSUMER_NAME ADDRESS-------------- ----------------------- -------------READY AQUSER2 [email protected] AQUSER1READY AQUSER3 AQADM.INQ In this example we see 2 messages ready to be propagated to remote queues and 1 that is not. If the address column is blank, the message is not scheduled for propagation and can only be dequeued from the queue upon which it was enqueued. The MSG_STATE column values are discussed in Document 102330.1 Advanced Queueing MSG_STATE Values and their Interpretation. If the address column has a value, the message has been enqueued for propagation to another queue. The first row in the example includes a database link (@M2V102.ES). This demonstrates that the message should be propagated to a queue at a remote database. The third row does not include a database link so will be propagated to a queue that resides on the same database as the source queue. The consumer name is the intended recipient at the target queue. Note that we are not querying the base queue table directly; rather, we are querying a view that is available on top of every queue table, AQ$<queue_table_name>.A more realistic query in an environment where the queue table contains thousands of messages is8.0.3-compatible multiple-consumer queue table and all compatibility single-consumer queue tables select count(*), MSG_STATE, QUEUE from AQ$<queue_table_name>  group by MSG_STATE, QUEUE; 8.1.3 and 10.0-compatible queue tables select count(*), MSG_STATE, QUEUE, CONSUMER_NAME from AQ$<queue_table_name>group by MSG_STATE, QUEUE, CONSUMER_NAME; For multiple-consumer queue tables, if you did not see the expected CONSUMER_NAME , check the syntax of the enqueue code and verify the recipients are declared correctly. If a recipients list is not used on enqueue, check the subscriber list in the AQ$_<queue_table_name>_S view (note that a single-consumer queue table does not have a subscriber view. This view records all members of the default subscription list which were added using the DBMS_AQADM.ADD_SUBSCRIBER procedure and also those enqueued using a recipient list. SQL> select QUEUE, NAME, ADDRESS from AQ$MULTIPLEQTABLE_S;QUEUE NAME ADDRESS---------- ----------- -------------MULTIPLEQ AQUSER2 [email protected] AQUSER1 In this example we have 2 subscribers registered with the queue. We have a local subscriber AQUSER1, and a remote subscriber AQUSER2, on the queue INQ, owned by AQADM, at M2V102.ES. Unless overridden with a recipient list during enqueue every message enqueued to this queue will be propagated to INQ at M2V102.ES.For 8.1 style and above multiple consumer queue tables, you can also check the following information at the target: select CONSUMER_NAME, DEQ_TXN_ID, DEQ_TIME, DEQ_USER_ID, PROPAGATED_MSGID from AQ$<queue_table_name> where QUEUE = '<QUEUE_NAME>'; For 8.0 style queues, if the queue table supports multiple consumers you can obtain the same information from the history column of the queue table: select h.CONSUMER, h.TRANSACTION_ID, h.DEQ_TIME, h.DEQ_USER, h.PROPAGATED_MSGIDfrom AQ$<queue_table_name> t, table(t.history) h where t.Q_NAME = '<QUEUE_NAME>'; A non-NULL TRANSACTION_ID indicates that the message was successfully propagated. Further, the DEQ_TIME indicates the time of propagation, the DEQ_USER indicates the userid used for propagation, and the PROPAGATED_MSGID indicates the message ID of the message that was enqueued at the destination. 6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment 6.1. Is the Propagation Enabled? For a propagation job to propagate messages, the propagation must be enabled. For Streams, a special view called DBA_PROPAGATION exists to convey information about Streams propagations. If messages are not being propagated by a propagation as expected, then the propagation might not be enabled. To query for this: SELECT p.PROPAGATION_NAME, DECODE(s.SCHEDULE_DISABLED, 'Y', 'Disabled','N', 'Enabled') SCHEDULE_DISABLED, s.PROCESS_NAME, s.FAILURES, s.LAST_ERROR_MSGFROM DBA_QUEUE_SCHEDULES s, DBA_PROPAGATION pWHERE p.DESTINATION_DBLINK = NVL(REGEXP_SUBSTR(s.DESTINATION, '[^@]+', 1, 2), s.DESTINATION) AND s.SCHEMA = p.SOURCE_QUEUE_OWNER AND s.QNAME = p.SOURCE_QUEUE_NAME AND MESSAGE_DELIVERY_MODE = 'PERSISTENT' order by PROPAGATION_NAME; At times, the propagation job may become "broken" or fail to start after an error has been encountered or after a database restart. If an error is indicated by the above query, an attempt to disable the propagation and then re-enable it can be made. In the examples below, for the propagation named STRMADMIN_PROPAGATE where the queue name is STREAMS_QUEUE owned by STRMADMIN and the destination database link is ORCL2.WORLD, the commands would be:10.2 and above exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE'); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); If the above does not fix the problem, stop the propagation specifying the force parameter (2nd parameter on stop_propagation) as TRUE: exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE',true); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); The statistics for the propagation as well as any old error messages are cleared when the force parameter is set to TRUE. Therefore if the propagation schedule is stopped with FORCE set to TRUE, and upon restart there is still an error message in DBA_PROPAGATION, then the error message is current.9.2 or 10.1 exec dbms_aqadm.disable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms.aqadm.enable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); If the above does not fix the problem, perform an unschedule of propagation and then schedule_propagation: exec dbms_aqadm.unschedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms_aqadm.schedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); Typically if the error from the first query in Section 6.1 recurs after restarting the propagation as shown above, further troubleshooting of the error is needed. 6.2. Check Propagation Rule Sets and Transformations Inspect the configuration of the rules in the rule set that is associated with the propagation process to make sure that they evaluate to TRUE as expected. If not, then the object or schema will not be propagated. Remember that when a negative rule evaluates to TRUE, the specified object or schema will not be propagated. Finally inspect any rule-based transformations that are implemented with propagation to make sure they are changing the data in the intended way.The following query shows what rule sets are assigned to a propagation: select PROPAGATION_NAME, RULE_SET_OWNER||'.'||RULE_SET_NAME "Positive Rule Set",NEGATIVE_RULE_SET_OWNER||'.'||NEGATIVE_RULE_SET_NAME "Negative Rule Set"from DBA_PROPAGATION; The next two queries list the propagation rules and their conditions. The first is for the positive rule set, the second is for the negative rule set: set long 4000select rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES rwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER and RULE_SET_NAME in(select RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME;   set long 4000select c.PROPAGATION_NAME, rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES r ,DBA_PROPAGATION cwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER andrsr.RULE_SET_OWNER=c.NEGATIVE_RULE_SET_OWNER and rsr.RULE_SET_NAME=c.NEGATIVE_RULE_SET_NAMEand rsr.RULE_SET_NAME in(select NEGATIVE_RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME; 6.3. Determining the Total Number of Messages and Bytes Propagated As in Section 3.1, determining if messages are flowing can be instructive to see whether the propagation is entirely hung or just slow. If the propagation is not in flow control (see Section 6.5.2), but the statistics are incrementing slowly, there may be a performance issue. For Streams implementations two views are available that can assist with this that can show the number of messages sent by a propagation, as well as the number of acknowledgements being returned from the target site: the V$PROPAGATION_SENDER view at the Source site and the V$PROPAGATION_RECEIVER view at the destination site. It is helpful to query both to determine if messages are being delivered to the target. Look for the statistics to increase.Source: select QUEUE_SCHEMA, QUEUE_NAME, DBLINK,HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS, TOTAL_BYTESfrom V$PROPAGATION_SENDER; Target: select SRC_QUEUE_SCHEMA, SRC_QUEUE_NAME, SRC_DBNAME, DST_QUEUE_SCHEMA, DST_QUEUE_NAME, HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS from V$PROPAGATION_RECEIVER; 6.4. Check Buffered Subscribers The V$BUFFERED_SUBSCRIBERS view displays information about subscribers for all buffered queues in the instance. This view can be queried to make sure that the site that the propagation is propagating to is listed as a subscriber address for the site being propagated from: select QUEUE_SCHEMA, QUEUE_NAME, SUBSCRIBER_ADDRESS from V$BUFFERED_SUBSCRIBERS; The SUBSCRIBER_ADDRESS column will not be populated when the propagation is local (between queues on the same database). 6.5. Common Streams Propagation Errors 6.5.1. ORA-02082: A loopback database link must have a connection qualifier. This error can occur if you use the Streams Setup Wizard in Oracle Enterprise Manager without first configuring the GLOBAL_NAME for your database. 6.5.2. ORA-25307: Enqueue rate too high. Enable flow control DBA_QUEUE_SCHEDULES will display this informational message for propagation when the automatic flow control (10g feature of Streams) has been invoked.Similar to Streams capture processes, a Streams propagation process can also go into a state of 'flow control. This is an informative message that indicates flow control has been automatically enabled to reduce the rate at which messages are being enqueued into at target queue.This typically occurs when the target site is unable to keep up with the rate of messages flowing from the source site. Other than checking that the apply process is running normally on the target site, usually no action is required by the DBA. Propagation and the capture process will be resumed automatically when the target site is able to accept more messages.The following document contains more information:Document 302109.1 Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlSee the following document for one potential cause of this situation:Document 1097115.1 Oracle Streams Apply Reader is in 'Paused' State 6.5.3. ORA-25315 unsupported configuration for propagation of buffered messages This error typically occurs when the target database is RAC and usually indicates that an attempt was made to propagate buffered messages with the database link pointing to an instance in the destination database which is not the owner instance of the destination queue. To resolve the problem, use queue-to-queue propagation for buffered messages. 6.5.4. ORA-600 [KWQBMCRCPTS101] after dropping / recreating propagation For cause/fixes refer to:Document 421237.1 ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams Propagation 6.5.5. Stopping or Dropping a Streams Propagation Hangs See the following note:Document 1159787.1 Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It Hang 6.6. Streams Propagation-Related Notes for Common Issues Document 437838.1 Streams Specific PatchesDocument 749181.1 How to Recover Streams After Dropping PropagationDocument 368912.1 Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentDocument 564649.1 ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveDocument 553017.1 Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201Document 944846.1 Streams Propagation Fails Ora-7445 [kohrsmc]Document 745601.1 ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'Document 333068.1 ORA-23603: Streams Enqueue Aborted Eue To Low SGADocument 363496.1 Ora-25315 Propagating on RAC StreamsDocument 368237.1 Unable to Unschedule Propagation. Streams Queue is InvalidDocument 436332.1 dbms_propagation_adm.stop_propagation hangsDocument 727389.1 Propagation Fails With ORA-12528Document 730911.1 ORA-4063 Is Reported After Dropping Negative Prop.RulesetDocument 460471.1 Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsDocument 1165583.1 ORA-600 [kwqpuspse0-ack] In Streams EnvironmentDocument 1059029.1 Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationDocument 556309.1 Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedDocument 839568.1 Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''Document 311021.1 Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredDocument 359971.1 STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068Document 1101616.1 DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747 7. Performance Issues A propagation may seem to be slow if the queries from Sections 3.1 and 6.3 show that the message statistics are not changing quickly. In Oracle Streams, this more usually is due to a slow apply process at the target rather than a slow propagation. Propagation could be inferred to be slow if the message statistics are changing, and the state of a capture process according to V$STREAMS_CAPTURE.STATE is PAUSED FOR FLOW CONTROL, but an ORA-25307 'Enqueue rate too high. Enable flow control' warning is NOT observed in DBA_QUEUE_SCHEDULES per Section 6.5.2. If this is the case, see the following notes / white papers for suggestions to increase performance:Document 335516.1 Master Note for Streams Performance RecommendationsDocument 730036.1 Overview for Troubleshooting Streams Performance IssuesDocument 780733.1 Streams Propagation Tuning with Network ParametersWhite Paper: http://www.oracle.com/technetwork/database/features/availability/maa-wp-10gr2-streams-performance-130059.pdfWhite Paper: Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2, http://www.oracle.com/technetwork/database/features/availability/maa-10gr2-streams-configuration-132039.pdf, See APPENDIX A: USING STREAMS CONFIGURATIONS OVER A NETWORKFor basic AQ propagation, the network tuning in the aforementioned Appendix A of the white paper 'Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2' is applicable. References NOTE:102330.1 - Advanced Queueing MSG_STATE Values and their InterpretationNOTE:102771.1 - Advanced Queueing Propagation using PL/SQLNOTE:1059029.1 - Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationNOTE:1079577.1 - Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"NOTE:1083608.1 - 11g Streams and Oracle SchedulerNOTE:1087324.1 - ORA-01405 ORA-01422 reported by Adavanced Queueing Propagation schedules after RAC reconfigurationNOTE:1097115.1 - Oracle Streams Apply Reader is in 'Paused' StateNOTE:1101616.1 - DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747NOTE:1159787.1 - Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It HangNOTE:1165583.1 - ORA-600 [kwqpuspse0-ack] In Streams EnvironmentNOTE:118884.1 - How to unschedule a propagation schedule stuck in pending stateNOTE:1203544.1 - AQ PROPAGATION ABORTED WITH ORA-600[OCIKSIN: INVALID STATUS] ON SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE AFTER UPGRADENOTE:1204080.1 - AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.NOTE:219416.1 - Advanced Queuing Propagation fails with ORA-22922NOTE:222992.1 - DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082NOTE:253131.1 - Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555)NOTE:282987.1 - Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueNOTE:298015.1 - Kwqjswproc:Excep After Loop: Assigning To SelfNOTE:302109.1 - Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlNOTE:311021.1 - Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredNOTE:332792.1 - ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up StatspackNOTE:333068.1 - ORA-23603: Streams Enqueue Aborted Eue To Low SGANOTE:335516.1 - Master Note for Streams Performance RecommendationsNOTE:353325.1 - ORA-24056: Internal inconsistency for QUEUE and destination NOTE:353754.1 - Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT.NOTE:359971.1 - STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068NOTE:363496.1 - Ora-25315 Propagating on RAC StreamsNOTE:365093.1 - ORA-07445 [kwqppay2aqe()+7360] reported on Propagation of a Transformed MessageNOTE:368237.1 - Unable to Unschedule Propagation. Streams Queue is InvalidNOTE:368912.1 - Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentNOTE:421237.1 - ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams PropagationNOTE:436332.1 - dbms_propagation_adm.stop_propagation hangsNOTE:437838.1 - Streams Specific PatchesNOTE:460471.1 - Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsNOTE:463820.1 - Streams Combined Capture and Apply in 11gNOTE:553017.1 - Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201NOTE:556309.1 - Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedNOTE:564649.1 - ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveNOTE:566622.1 - ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1NOTE:727389.1 - Propagation Fails With ORA-12528NOTE:730036.1 - Overview for Troubleshooting Streams Performance IssuesNOTE:730911.1 - ORA-4063 Is Reported After Dropping Negative Prop.RulesetNOTE:731292.1 - ORA-25215 Reported On Local Propagation When Using Transformation with ANYDATA queue tablesNOTE:731539.1 - ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTPNOTE:745601.1 - ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'NOTE:749181.1 - How to Recover Streams After Dropping PropagationNOTE:780733.1 - Streams Propagation Tuning with Network ParametersNOTE:787367.1 - ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2NOTE:808136.1 - How to clear the old errors from DBA_PROPAGATION view ?NOTE:827184.1 - AQ Propagation with CLOB data types Fails with ORA-22990NOTE:827473.1 - How to alter propagation from queue_to_queue to queue_to_dblinkNOTE:839568.1 - Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''NOTE:846297.1 - AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn]NOTE:944846.1 - Streams Propagation Fails Ora-7445 [kohrsmc]

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  • Designing for the future

    - by Dennis Vroegop
    User interfaces and user experience design is a fast moving field. It’s something that changes pretty quick: what feels fresh today will look outdated tomorrow. I remember the day I first got a beta version of Windows 95 and I felt swept away by the user interface of the OS. It felt so modern! If I look back now, it feels old. Well, it should: the design is 17 years old which is an eternity in our field. Of course, this is not limited to UI. Same goes for many industries. I want you to think back of the cars that amazed you when you were in your teens (if you are in your teens then this may not apply to you). Didn’t they feel like part of the future? Didn’t you think that this was the ultimate in designs? And aren’t those designs hopelessly outdated today (again, depending on your age, it may just be me)? Let’s review the Win95 design: And let’s compare that to Windows 7: There are so many differences here, I wouldn’t even know where to start explaining them. The general feeling however is one of more usability: studies have shown Windows 7 is much easier to understand for new users than the older versions of Windows did. Of course, experienced Windows users didn’t like it: people are usually afraid of changes and like to stick to what they know. But for new users this was a huge improvement. And that is what UX design is all about: make a product easier to use, with less training required and make users feel more productive. Still, there are areas where this doesn’t hold up. There are plenty examples of designs from the past that are still fresh today. But if you look closely at them, you’ll notice some subtle differences. This differences are what keep the designs fresh. A good example is the signs you’ll find on the road. They haven’t changed much over the years (otherwise people wouldn’t recognize them anymore) but they have been changing gradually to reflect changes in traffic. The same goes for computer interfaces. With each new product or version of a product, the UI and UX is changed gradually. Every now and then however, a bigger change is needed. Just think about the introduction of the Ribbon in Microsoft Office 2007: the whole UI was redesigned. A lot of old users (not in age, but in times of using older versions) didn’t like it a bit, but new users or casual users seem to be more efficient using the product. Which, of course, is exactly the reason behind the changes. I believe that a big engine behind the changes in User Experience design has been the web. In the old days (i.e. before the explosion of the internet) user interface design in Windows applications was limited to choosing the margins between your battleship gray buttons. When the web came along, and especially the web 2.0 where the browsers started to act more and more as application platforms, designers stepped in and made a huge impact. In the browser, they could do whatever they wanted. In the beginning this was limited to the darn blink tag but gradually people really started to think about UX. Even more so: the design of the UI and the whole experience was taken away from the developers and put into the hands of people who knew what they were doing: UX designers. This caused some problems. Everyone who has done a web project in the early 2000’s must have had the same experience: the designers give you a set of Photoshop files and tell you to translate it to HTML. Which, of course, is very hard to do. However, with new tooling and new standards this became much easier. The latest version of HTML and CSS has taken the responsibility for the design away from the developers and placed them in the capable hands of the designers. And that’s where that responsibility belongs, after all, I don’t want a designer to muck around in my c# code just as much as he or she doesn’t want me to poke in the sites style definitions. This change in responsibilities resulted in good looking but more important: better thought out user interfaces in websites. And when websites became more and more interactive, people started to expect the same sort of look and feel from their desktop applications. But that didn’t really happen. Most business applications still have that battleship gray look and feel. Ok, they may use a different color but we’re not talking colors here but usability. Now, you may not be able to read the Dutch captions, but even if you did you wouldn’t understand what was going on. At least, not when you first see it. You have to scan the screen, read all the labels, see how they are related to the other elements on the screen and then figure out what they do. If you’re an experienced user of this application however, this might be a good thing: you know what to do and you get all the information you need in one single screen. But for most applications this isn’t the case. A lot of people only use their computer for a limited time a day (a weird concept for me, but it happens) and need it to get something done and then get on with their lives. For them, a user interface experience like the above isn’t working. (disclaimer: I just picked a screenshot, I am not saying this is bad software but it is an example of about 95% of the Windows applications out there). For the knowledge worker, this isn’t a problem. They use one or two systems and they know exactly what they need to do to achieve their goal. They don’t want any clutter on their screen that distracts them from their task, they just want to be as efficient as possible. When they know the systems they are very productive. The point is, how long does it take to become productive? And: could they be even more productive if the UX was better? Are there things missing that they don’t know about? Are there better ways to achieve what they want to achieve? Also: could a system be designed in such a way that it is not only much more easy to work with but also less tiring? in the example above you need to switch between the keyboard and mouse a lot, something that we now know can be very tiring. The goal of most applications (being client apps or websites on any kind of device) is to provide information. Information is data that when given to the right people, on the right time, in the right place and when it is correct adds value for that person (please, remember that definition: I still hear the statement “the information was wrong” which doesn’t make sense: data can be wrong, information cannot be). So if a system provides data, how can we make sure the chances of becoming information is as high as possible? A good example of a well thought-out system that attempts this is the Zune client. It is a very good application, and I think the UX is much better than it’s main competitor iTunes. Have a look at both: On the left you see the iTunes screenshot, on the right the Zune. As you notice, the Zune screen has more images but less chrome (chrome being visuals not part of the data you want to show, i.e. edges around buttons). The whole thing is text oriented or image oriented, where that text or image is part of the information you need. What is important is big, what’s less important is smaller. Yet, everything you need to know at that point is present and your attention is drawn immediately to what you’re trying to achieve: information about music. You can easily switch between the content on your machine and content on your Zune player but clicking on the image of the player. But if you didn’t know that, you’d find out soon enough: the whole UX is designed in such a way that it invites you to play around. So sooner or later (probably sooner) you’d click on that image and you would see what it does. In the iTunes version it’s harder to find: the discoverability is a lot lower. For inexperienced people the Zune player feels much more natural than the iTunes player, and they get up to speed a lot faster. How does this all work? Why is this UX better? The answer lies in a project from Microsoft with the codename (it seems to be becoming the official name though) “Metro”. Metro is a design language, based on certain principles. When they thought about UX they took a good long look around them and went out in search of metaphors. And they found them. The team noticed that signage in streets, airports, roads, buildings and so on are usually very clear and very precise. These signs give you the information you need and nothing more. It’s simple, clearly understood and fast to understand. A good example are airport signs. Airports can be intimidating places, especially for the non-experienced traveler. In the early 1990’s Amsterdam Airport Schiphol decided to redesign all the signage to make the traveller feel less disoriented. They developed a set of guidelines for signs and implemented those. Soon, most airports around the world adopted these ideas and you see variations of the Dutch signs everywhere on the globe. The signs are text-oriented. Yes, there are icons explaining what it all means for the people who can’t read or don’t understand the language, but the basic sign language is text. It’s clear, it’s high-contrast and it’s easy to understand. One look at the sign and you know where to go. The only thing I don’t like is the green sign pointing to the emergency exit, but since this is the default style for emergency exits I understand why they did this. If you look at the Zune UI again, you’ll notice the similarities. Text oriented, little or no icons, clear usage of fonts and all the information you need. This design language has a set of principles: Clean, light, open and fast Content, not chrome Soulful and alive These are just a couple of the principles, you can read the whole philosophy behind Metro for Windows Phone 7 here. These ideas seem to work. I love my Windows Phone 7. It’s easy to use, it’s clear, there’s no clutter that I do not need. It works for me. And I noticed it works for a lot of other people as well, especially people who aren’t as proficient with computers as I am. You see these ideas in a lot other places. Corning, a manufacturer of glass, has made a video of possible usages of their products. It’s their glimpse into the future. You’ll notice that a lot of the UI in the screens look a lot like what Microsoft is doing with Metro (not coincidentally Corning is the supplier for the Gorilla glass display surface on the new SUR40 device (or Surface v2.0 as a lot of people call it)). The idea behind this vision is that data should be available everywhere where you it. Systems should be available at all times and data is presented in a clear and light manner so that you can turn that data into information. You don’t need a lot of fancy animations that only distract from the data. You want the data and you want it fast. Have a look at this truly inspiring video that made: This is what I believe the future will look like. Of course, not everything is possible, or even desirable. But it is a nice way to think about the future . I feel very strongly about designing applications in such a way that they add value to the user. Designing applications that turn data into information. Applications that make the user feel happy to use them. So… when are you going to drop the battleship-gray designs? Tags van Technorati: surface,design,windows phone 7,wp7,metro

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  • The Benefits of Smart Grid Business Software

    - by Sylvie MacKenzie, PMP
    Smart Grid Background What Are Smart Grids?Smart Grids use computer hardware and software, sensors, controls, and telecommunications equipment and services to: Link customers to information that helps them manage consumption and use electricity wisely. Enable customers to respond to utility notices in ways that help minimize the duration of overloads, bottlenecks, and outages. Provide utilities with information that helps them improve performance and control costs. What Is Driving Smart Grid Development? Environmental ImpactSmart Grid development is picking up speed because of the widespread interest in reducing the negative impact that energy use has on the environment. Smart Grids use technology to drive efficiencies in transmission, distribution, and consumption. As a result, utilities can serve customers’ power needs with fewer generating plants, fewer transmission and distribution assets,and lower overall generation. With the possible exception of wind farm sprawl, landscape preservation is one obvious benefit. And because most generation today results in greenhouse gas emissions, Smart Grids reduce air pollution and the potential for global climate change.Smart Grids also more easily accommodate the technical difficulties of integrating intermittent renewable resources like wind and solar into the grid, providing further greenhouse gas reductions. CostsThe ability to defer the cost of plant and grid expansion is a major benefit to both utilities and customers. Utilities do not need to use as many internal resources for traditional infrastructure project planning and management. Large T&D infrastructure expansion costs are not passed on to customers.Smart Grids will not eliminate capital expansion, of course. Transmission corridors to connect renewable generation with customers will require major near-term expenditures. Additionally, in the future, electricity to satisfy the needs of population growth and additional applications will exceed the capacity reductions available through the Smart Grid. At that point, expansion will resume—but with greater overall T&D efficiency based on demand response, load control, and many other Smart Grid technologies and business processes. Energy efficiency is a second area of Smart Grid cost saving of particular relevance to customers. The timely and detailed information Smart Grids provide encourages customers to limit waste, adopt energy-efficient building codes and standards, and invest in energy efficient appliances. Efficiency may or may not lower customer bills because customer efficiency savings may be offset by higher costs in generation fuels or carbon taxes. It is clear, however, that bills will be lower with efficiency than without it. Utility Operations Smart Grids can serve as the central focus of utility initiatives to improve business processes. Many utilities have long “wish lists” of projects and applications they would like to fund in order to improve customer service or ease staff’s burden of repetitious work, but they have difficulty cost-justifying the changes, especially in the short term. Adding Smart Grid benefits to the cost/benefit analysis frequently tips the scales in favor of the change and can also significantly reduce payback periods.Mobile workforce applications and asset management applications work together to deploy assets and then to maintain, repair, and replace them. Many additional benefits result—for instance, increased productivity and fuel savings from better routing. Similarly, customer portals that provide customers with near-real-time information can also encourage online payments, thus lowering billing costs. Utilities can and should include these cost and service improvements in the list of Smart Grid benefits. What Is Smart Grid Business Software? Smart Grid business software gathers data from a Smart Grid and uses it improve a utility’s business processes. Smart Grid business software also helps utilities provide relevant information to customers who can then use it to reduce their own consumption and improve their environmental profiles. Smart Grid Business Software Minimizes the Impact of Peak Demand Utilities must size their assets to accommodate their highest peak demand. The higher the peak rises above base demand: The more assets a utility must build that are used only for brief periods—an inefficient use of capital. The higher the utility’s risk profile rises given the uncertainties surrounding the time needed for permitting, building, and recouping costs. The higher the costs for utilities to purchase supply, because generators can charge more for contracts and spot supply during high-demand periods. Smart Grids enable a variety of programs that reduce peak demand, including: Time-of-use pricing and critical peak pricing—programs that charge customers more when they consume electricity during peak periods. Pilot projects indicate that these programs are successful in flattening peaks, thus ensuring better use of existing T&D and generation assets. Direct load control, which lets utilities reduce or eliminate electricity flow to customer equipment (such as air conditioners). Contracts govern the terms and conditions of these turn-offs. Indirect load control, which signals customers to reduce the use of on-premises equipment for contractually agreed-on time periods. Smart Grid business software enables utilities to impose penalties on customers who do not comply with their contracts. Smart Grids also help utilities manage peaks with existing assets by enabling: Real-time asset monitoring and control. In this application, advanced sensors safely enable dynamic capacity load limits, ensuring that all grid assets can be used to their maximum capacity during peak demand periods. Real-time asset monitoring and control applications also detect the location of excessive losses and pinpoint need for mitigation and asset replacements. As a result, utilities reduce outage risk and guard against excess capacity or “over-build”. Better peak demand analysis. As a result: Distribution planners can better size equipment (e.g. transformers) to avoid over-building. Operations engineers can identify and resolve bottlenecks and other inefficiencies that may cause or exacerbate peaks. As above, the result is a reduction in the tendency to over-build. Supply managers can more closely match procurement with delivery. As a result, they can fine-tune supply portfolios, reducing the tendency to over-contract for peak supply and reducing the need to resort to spot market purchases during high peaks. Smart Grids can help lower the cost of remaining peaks by: Standardizing interconnections for new distributed resources (such as electricity storage devices). Placing the interconnections where needed to support anticipated grid congestion. Smart Grid Business Software Lowers the Cost of Field Services By processing Smart Grid data through their business software, utilities can reduce such field costs as: Vegetation management. Smart Grids can pinpoint momentary interruptions and tree-caused outages. Spatial mash-up tools leverage GIS models of tree growth for targeted vegetation management. This reduces the cost of unnecessary tree trimming. Service vehicle fuel. Many utility service calls are “false alarms.” Checking meter status before dispatching crews prevents many unnecessary “truck rolls.” Similarly, crews use far less fuel when Smart Grid sensors can pinpoint a problem and mobile workforce applications can then route them directly to it. Smart Grid Business Software Ensures Regulatory Compliance Smart Grids can ensure compliance with private contracts and with regional, national, or international requirements by: Monitoring fulfillment of contract terms. Utilities can use one-hour interval meters to ensure that interruptible (“non-core”) customers actually reduce or eliminate deliveries as required. They can use the information to levy fines against contract violators. Monitoring regulations imposed on customers, such as maximum use during specific time periods. Using accurate time-stamped event history derived from intelligent devices distributed throughout the smart grid to monitor and report reliability statistics and risk compliance. Automating business processes and activities that ensure compliance with security and reliability measures (e.g. NERC-CIP 2-9). Grid Business Software Strengthens Utilities’ Connection to Customers While Reducing Customer Service Costs During outages, Smart Grid business software can: Identify outages more quickly. Software uses sensors to pinpoint outages and nested outage locations. They also permit utilities to ensure outage resolution at every meter location. Size outages more accurately, permitting utilities to dispatch crews that have the skills needed, in appropriate numbers. Provide updates on outage location and expected duration. This information helps call centers inform customers about the timing of service restoration. Smart Grids also facilitates display of outage maps for customer and public-service use. Smart Grids can significantly reduce the cost to: Connect and disconnect customers. Meters capable of remote disconnect can virtually eliminate the costs of field crews and vehicles previously required to change service from the old to the new residents of a metered property or disconnect customers for nonpayment. Resolve reports of voltage fluctuation. Smart Grids gather and report voltage and power quality data from meters and grid sensors, enabling utilities to pinpoint reported problems or resolve them before customers complain. Detect and resolve non-technical losses (e.g. theft). Smart Grids can identify illegal attempts to reconnect meters or to use electricity in supposedly vacant premises. They can also detect theft by comparing flows through delivery assets with billed consumption. Smart Grids also facilitate outreach to customers. By monitoring and analyzing consumption over time, utilities can: Identify customers with unusually high usage and contact them before they receive a bill. They can also suggest conservation techniques that might help to limit consumption. This can head off “high bill” complaints to the contact center. Note that such “high usage” or “additional charges apply because you are out of range” notices—frequently via text messaging—are already common among mobile phone providers. Help customers identify appropriate bill payment alternatives (budget billing, prepayment, etc.). Help customers find and reduce causes of over-consumption. There’s no waiting for bills in the mail before they even understand there is a problem. Utilities benefit not just through improved customer relations but also through limiting the size of bills from customers who might struggle to pay them. Where permitted, Smart Grids can open the doors to such new utility service offerings as: Monitoring properties. Landlords reduce costs of vacant properties when utilities notify them of unexpected energy or water consumption. Utilities can perform similar services for owners of vacation properties or the adult children of aging parents. Monitoring equipment. Power-use patterns can reveal a need for equipment maintenance. Smart Grids permit utilities to alert owners or managers to a need for maintenance or replacement. Facilitating home and small-business networks. Smart Grids can provide a gateway to equipment networks that automate control or let owners access equipment remotely. They also facilitate net metering, offering some utilities a path toward involvement in small-scale solar or wind generation. Prepayment plans that do not need special meters. Smart Grid Business Software Helps Customers Control Energy Costs There is no end to the ways Smart Grids help both small and large customers control energy costs. For instance: Multi-premises customers appreciate having all meters read on the same day so that they can more easily compare consumption at various sites. Customers in competitive regions can match their consumption profile (detailed via Smart Grid data) with specific offerings from competitive suppliers. Customers seeing inexplicable consumption patterns and power quality problems may investigate further. The result can be discovery of electrical problems that can be resolved through rewiring or maintenance—before more serious fires or accidents happen. Smart Grid Business Software Facilitates Use of Renewables Generation from wind and solar resources is a popular alternative to fossil fuel generation, which emits greenhouse gases. Wind and solar generation may also increase energy security in regions that currently import fossil fuel for use in generation. Utilities face many technical issues as they attempt to integrate intermittent resource generation into traditional grids, which traditionally handle only fully dispatchable generation. Smart Grid business software helps solves many of these issues by: Detecting sudden drops in production from renewables-generated electricity (wind and solar) and automatically triggering electricity storage and smart appliance response to compensate as needed. Supporting industry-standard distributed generation interconnection processes to reduce interconnection costs and avoid adding renewable supplies to locations already subject to grid congestion. Facilitating modeling and monitoring of locally generated supply from renewables and thus helping to maximize their use. Increasing the efficiency of “net metering” (through which utilities can use electricity generated by customers) by: Providing data for analysis. Integrating the production and consumption aspects of customer accounts. During non-peak periods, such techniques enable utilities to increase the percent of renewable generation in their supply mix. During peak periods, Smart Grid business software controls circuit reconfiguration to maximize available capacity. Conclusion Utility missions are changing. Yesterday, they focused on delivery of reasonably priced energy and water. Tomorrow, their missions will expand to encompass sustainable use and environmental improvement.Smart Grids are key to helping utilities achieve this expanded mission. But they come at a relatively high price. Utilities will need to invest heavily in new hardware, software, business process development, and staff training. Customer investments in home area networks and smart appliances will be large. Learning to change the energy and water consumption habits of a lifetime could ultimately prove even more formidable tasks.Smart Grid business software can ease the cost and difficulties inherent in a needed transition to a more flexible, reliable, responsive electricity grid. Justifying its implementation, however, requires a full understanding of the benefits it brings—benefits that can ultimately help customers, utilities, communities, and the world address global issues like energy security and climate change while minimizing costs and maximizing customer convenience. This white paper is available for download here. For further information about Oracle's Primavera Solutions for Utilities, please read our Utilities e-book.

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  • Windows Azure: Major Updates for Mobile Backend Development

    - by ScottGu
    This week we released some great updates to Windows Azure that make it significantly easier to develop mobile applications that use the cloud. These new capabilities include: Mobile Services: Custom API support Mobile Services: Git Source Control support Mobile Services: Node.js NPM Module support Mobile Services: A .NET API via NuGet Mobile Services and Web Sites: Free 20MB SQL Database Option for Mobile Services and Web Sites Mobile Notification Hubs: Android Broadcast Push Notification Support All of these improvements are now available to use immediately (note: some are still in preview).  Below are more details about them. Mobile Services: Custom APIs, Git Source Control, and NuGet Windows Azure Mobile Services provides the ability to easily stand up a mobile backend that can be used to support your Windows 8, Windows Phone, iOS, Android and HTML5 client applications.  Starting with the first preview we supported the ability to easily extend your data backend logic with server side scripting that executes as part of client-side CRUD operations against your cloud back data tables. With today’s update we are extending this support even further and introducing the ability for you to also create and expose Custom APIs from your Mobile Service backend, and easily publish them to your Mobile clients without having to associate them with a data table. This capability enables a whole set of new scenarios – including the ability to work with data sources other than SQL Databases (for example: Table Services or MongoDB), broker calls to 3rd party APIs, integrate with Windows Azure Queues or Service Bus, work with custom non-JSON payloads (e.g. Windows Periodic Notifications), route client requests to services back on-premises (e.g. with the new Windows Azure BizTalk Services), or simply implement functionality that doesn’t correspond to a database operation.  The custom APIs can be written in server-side JavaScript (using Node.js) and can use Node’s NPM packages.  We will also be adding support for custom APIs written using .NET in the future as well. Creating a Custom API Adding a custom API to an existing Mobile Service is super easy.  Using the Windows Azure Management Portal you can now simply click the new “API” tab with your Mobile Service, and then click the “Create a Custom API” button to create a new Custom API within it: Give the API whatever name you want to expose, and then choose the security permissions you’d like to apply to the HTTP methods you expose within it.  You can easily lock down the HTTP verbs to your Custom API to be available to anyone, only those who have a valid application key, only authenticated users, or administrators.  Mobile Services will then enforce these permissions without you having to write any code: When you click the ok button you’ll see the new API show up in the API list.  Selecting it will enable you to edit the default script that contains some placeholder functionality: Today’s release enables Custom APIs to be written using Node.js (we will support writing Custom APIs in .NET as well in a future release), and the Custom API programming model follows the Node.js convention for modules, which is to export functions to handle HTTP requests. The default script above exposes functionality for an HTTP POST request. To support a GET, simply change the export statement accordingly.  Below is an example of some code for reading and returning data from Windows Azure Table Storage using the Azure Node API: After saving the changes, you can now call this API from any Mobile Service client application (including Windows 8, Windows Phone, iOS, Android or HTML5 with CORS). Below is the code for how you could invoke the API asynchronously from a Windows Store application using .NET and the new InvokeApiAsync method, and data-bind the results to control within your XAML:     private async void RefreshTodoItems() {         var results = await App.MobileService.InvokeApiAsync<List<TodoItem>>("todos", HttpMethod.Get, parameters: null);         ListItems.ItemsSource = new ObservableCollection<TodoItem>(results);     }    Integrating authentication and authorization with Custom APIs is really easy with Mobile Services. Just like with data requests, custom API requests enjoy the same built-in authentication and authorization support of Mobile Services (including integration with Microsoft ID, Google, Facebook and Twitter authentication providers), and it also enables you to easily integrate your Custom API code with other Mobile Service capabilities like push notifications, logging, SQL, etc. Check out our new tutorials to learn more about to use new Custom API support, and starting adding them to your app today. Mobile Services: Git Source Control Support Today’s Mobile Services update also enables source control integration with Git.  The new source control support provides a Git repository as part your Mobile Service, and it includes all of your existing Mobile Service scripts and permissions. You can clone that git repository on your local machine, make changes to any of your scripts, and then easily deploy the mobile service to production using Git. This enables a really great developer workflow that works on any developer machine (Windows, Mac and Linux). To use the new support, navigate to the dashboard for your mobile service and select the Set up source control link: If this is your first time enabling Git within Windows Azure, you will be prompted to enter the credentials you want to use to access the repository: Once you configure this, you can switch to the configure tab of your Mobile Service and you will see a Git URL you can use to use your repository: You can use this URL to clone the repository locally from your favorite command line: > git clone https://scottgutodo.scm.azure-mobile.net/ScottGuToDo.git Below is the directory structure of the repository: As you can see, the repository contains a service folder with several subfolders. Custom API scripts and associated permissions appear under the api folder as .js and .json files respectively (the .json files persist a JSON representation of the security settings for your endpoints). Similarly, table scripts and table permissions appear as .js and .json files, but since table scripts are separate per CRUD operation, they follow the naming convention of <tablename>.<operationname>.js. Finally, scheduled job scripts appear in the scheduler folder, and the shared folder is provided as a convenient location for you to store code shared by multiple scripts and a few miscellaneous things such as the APNS feedback script. Lets modify the table script todos.js file so that we have slightly better error handling when an exception occurs when we query our Table service: todos.js tableService.queryEntities(query, function(error, todoItems){     if (error) {         console.error("Error querying table: " + error);         response.send(500);     } else {         response.send(200, todoItems);     }        }); Save these changes, and now back in the command line prompt commit the changes and push them to the Mobile Services: > git add . > git commit –m "better error handling in todos.js" > git push Once deployment of the changes is complete, they will take effect immediately, and you will also see the changes be reflected in the portal: With the new Source Control feature, we’re making it really easy for you to edit your mobile service locally and push changes in an atomic fashion without sacrificing ease of use in the Windows Azure Portal. Mobile Services: NPM Module Support The new Mobile Services source control support also allows you to add any Node.js module you need in the scripts beyond the fixed set provided by Mobile Services. For example, you can easily switch to use Mongo instead of Windows Azure table in our example above. Set up Mongo DB by either purchasing a MongoLab subscription (which provides MongoDB as a Service) via the Windows Azure Store or set it up yourself on a Virtual Machine (either Windows or Linux). Then go the service folder of your local git repository and run the following command: > npm install mongoose This will add the Mongoose module to your Mobile Service scripts.  After that you can use and reference the Mongoose module in your custom API scripts to access your Mongo database: var mongoose = require('mongoose'); var schema = mongoose.Schema({ text: String, completed: Boolean });   exports.get = function (request, response) {     mongoose.connect('<your Mongo connection string> ');     TodoItemModel = mongoose.model('todoitem', schema);     TodoItemModel.find(function (err, items) {         if (err) {             console.log('error:' + err);             return response.send(500);         }         response.send(200, items);     }); }; Don’t forget to push your changes to your mobile service once you are done > git add . > git commit –m "Switched to use Mongo Labs" > git push Now our Mobile Service app is using Mongo DB! Note, with today’s update usage of custom Node.js modules is limited to Custom API scripts only. We will enable it in all scripts (including data and custom CRON tasks) shortly. New Mobile Services NuGet package, including .NET 4.5 support A few months ago we announced a new pre-release version of the Mobile Services client SDK based on portable class libraries (PCL). Today, we are excited to announce that this new library is now a stable .NET client SDK for mobile services and is no longer a pre-release package. Today’s update includes full support for Windows Store, Windows Phone 7.x, and .NET 4.5, which allows developers to use Mobile Services from ASP.NET or WPF applications. You can install and use this package today via NuGet. Mobile Services and Web Sites: Free 20MB Database for Mobile Services and Web Sites Starting today, every customer of Windows Azure gets one Free 20MB database to use for 12 months free (for both dev/test and production) with Web Sites and Mobile Services. When creating a Mobile Service or a Web Site, simply chose the new “Create a new Free 20MB database” option to take advantage of it: You can use this free SQL Database together with the 10 free Web Sites and 10 free Mobile Services you get with your Windows Azure subscription, or from any other Windows Azure VM or Cloud Service. Notification Hubs: Android Broadcast Push Notification Support Earlier this year, we introduced a new capability in Windows Azure for sending broadcast push notifications at high scale: Notification Hubs. In the initial preview of Notification Hubs you could use this support with both iOS and Windows devices.  Today we’re excited to announce new Notification Hubs support for sending push notifications to Android devices as well. Push notifications are a vital component of mobile applications.  They are critical not only in consumer apps, where they are used to increase app engagement and usage, but also in enterprise apps where up-to-date information increases employee responsiveness to business events.  You can use Notification Hubs to send push notifications to devices from any type of app (a Mobile Service, Web Site, Cloud Service or Virtual Machine). Notification Hubs provide you with the following capabilities: Cross-platform Push Notifications Support. Notification Hubs provide a common API to send push notifications to iOS, Android, or Windows Store at once.  Your app can send notifications in platform specific formats or in a platform-independent way.  Efficient Multicast. Notification Hubs are optimized to enable push notification broadcast to thousands or millions of devices with low latency.  Your server back-end can fire one message into a Notification Hub, and millions of push notifications can automatically be delivered to your users.  Devices and apps can specify a number of per-user tags when registering with a Notification Hub. These tags do not need to be pre-provisioned or disposed, and provide a very easy way to send filtered notifications to an infinite number of users/devices with a single API call.   Extreme Scale. Notification Hubs enable you to reach millions of devices without you having to re-architect or shard your application.  The pub/sub routing mechanism allows you to broadcast notifications in a super-efficient way.  This makes it incredibly easy to route and deliver notification messages to millions of users without having to build your own routing infrastructure. Usable from any Backend App. Notification Hubs can be easily integrated into any back-end server app, whether it is a Mobile Service, a Web Site, a Cloud Service or an IAAS VM. It is easy to configure Notification Hubs to send push notifications to Android. Create a new Notification Hub within the Windows Azure Management Portal (New->App Services->Service Bus->Notification Hub): Then register for Google Cloud Messaging using https://code.google.com/apis/console and obtain your API key, then simply paste that key on the Configure tab of your Notification Hub management page under the Google Cloud Messaging Settings: Then just add code to the OnCreate method of your Android app’s MainActivity class to register the device with Notification Hubs: gcm = GoogleCloudMessaging.getInstance(this); String connectionString = "<your listen access connection string>"; hub = new NotificationHub("<your notification hub name>", connectionString, this); String regid = gcm.register(SENDER_ID); hub.register(regid, "myTag"); Now you can broadcast notification from your .NET backend (or Node, Java, or PHP) to any Windows Store, Android, or iOS device registered for “myTag” tag via a single API call (you can literally broadcast messages to millions of clients you have registered with just one API call): var hubClient = NotificationHubClient.CreateClientFromConnectionString(                   “<your connection string with full access>”,                   "<your notification hub name>"); hubClient.SendGcmNativeNotification("{ 'data' : {'msg' : 'Hello from Windows Azure!' } }", "myTag”); Notification Hubs provide an extremely scalable, cross-platform, push notification infrastructure that enables you to efficiently route push notification messages to millions of mobile users and devices.  It will make enabling your push notification logic significantly simpler and more scalable, and allow you to build even better apps with it. Learn more about Notification Hubs here on MSDN . Summary The above features are now live and available to start using immediately (note: some of the services are still in preview).  If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using them today.  Visit the Windows Azure Developer Center to learn more about how to build apps with it. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • Project Management Helps AmeriCares Deliver International Aid

    - by Sylvie MacKenzie, PMP
    Excerpt from PROFIT - ORACLE - by Alison Weiss Handle with Care Sound project management helps AmeriCares bring international aid to those in need. The stakes are always high for AmeriCares. On a mission to restore health and save lives during times of disaster, the nonprofit international relief and humanitarian aid organization delivers donated medicines, medical supplies, and humanitarian aid to people in the U.S. and around the globe. Founded in 1982 with the express mission of responding as quickly and efficiently as possible to help people in need, the Stamford, Connecticut-based AmeriCares has delivered more than US$10.5 billion in aid to 147 countries over the past three decades. Launch the Slideshow “It’s critically important to us that we steward all the donations and that the medical supplies and medicines get to people as quickly as possible with no loss,” says Kate Sears, senior vice president for finance and technology at AmeriCares. “Whether we’re shipping IV solutions to victims of cholera in Haiti or antibiotics to Somali famine victims, we need to get the medicines there sooner because it means more people will be helped and lives improved or even saved.” Ten years ago, the tracking systems used by AmeriCares associates were paper-based. In recent years, staff started using spreadsheets, but the tracking processes were not standardized between teams. “Every team was tracking completely different information,” says Megan McDermott, senior associate, Sub-Saharan Africa partnerships, at AmeriCares. “It was just a few key things. For example, we tracked the date a shipment was supposed to arrive and the date we got reports from our partner that a hospital received aid on their end.” While the data was accurate, much detail was being lost in the process. AmeriCares management knew it could do a better job of tracking this enterprise data and in 2011 took a significant step by implementing Oracle’s Primavera P6 Professional Project Management. “It’s a comprehensive solution that has helped us improve the monitoring and controlling processes. It has allowed us to do our distribution better,” says Sears. In addition, the implementation effort has been a change agent, helping AmeriCares leadership rethink project management across the entire organization. Initially, much of the focus was on standardizing processes, but staff members also learned the importance of thinking proactively to prevent possible problems and evaluating results to determine if goals and objectives are truly being met. Such data about process efficiency and overall results is critical not only to AmeriCares staff but also to the donors supporting the organization’s life-saving missions. Efficiency Saves Lives One of AmeriCares’ core operations is to gather product donations from the private sector, establish where the most-urgent needs are, and solicit monetary support to send the aid via ocean cargo or airlift to welfare- and health-oriented nongovernmental organizations, hospitals, health networks, and government ministries based in areas in need. In 2011 alone, AmeriCares sent more than 3,500 shipments to 95 countries in response to both ongoing humanitarian needs and more than two dozen emergencies, including deadly tornadoes and storms in the U.S. and the devastating tsunami in Japan. When it comes to nonprofits in general, donors want to know that the charitable organizations they support are using funds wisely. Typically, nonprofits are evaluated by donors in terms of efficiency, an area where AmeriCares has an excellent reputation: 98 percent of expenses go directly to supporting programs and less than 2 percent represent administrative and fundraising costs. Donors, however, should look at more than simple efficiency, says Peter York, senior partner and chief research and learning officer at TCC Group, a nonprofit consultancy headquartered in New York, New York. They should also look at whether organizations have the systems in place to sustain their missions and continue to thrive. An expert on nonprofit organizational management, York has spent years studying sustainable charitable organizations. He defines them as nonprofits that are able to achieve the ongoing financial support to stay relevant and continue doing core mission work. In his analysis of well over 2,500 larger nonprofits, York has found that many are not sustaining, and are actually scaling back in size. “One of the biggest challenges of nonprofit sustainability is the general public’s perception that every dollar donated has to go only to the delivery of service,” says York. “What our data shows is that there are some fundamental capacities that have to be there in order for organizations to sustain and grow.” York’s research highlights the importance of data-driven leadership at successful nonprofits. “You’ve got to have the tools, the systems, and the technologies to get objective information on what you do, the people you serve, and the results you’re achieving,” says York. “If leaders don’t have the knowledge and the data, they can’t make the strategic decisions about programs to take organizations to the next level.” Historically, AmeriCares associates have used time-tested and cost-effective strategies to ship and then track supplies from donation to delivery to their destinations in designated time frames. When disaster strikes, AmeriCares ships by air and generally pulls out all the stops to deliver the most urgently needed aid within the first few days and weeks. Then, as situations stabilize, AmeriCares turns to delivering sea containers for the postemergency and ongoing aid so often needed over the long term. According to McDermott, getting a shipment out the door is fairly complicated, requiring as many as five different AmeriCares teams collaborating together. The entire process can take months—from when products are received in the warehouse and deciding which recipients to allocate supplies to, to getting customs and governmental approvals in place, actually shipping products, and finally ensuring that the products are received in-country. Delivering that aid is no small affair. “Our volume exceeds half a billion dollars a year worth of donated medicines and medical supplies, so it’s a sizable logistical operation to bring these products in and get them out to the right place quickly to have the most impact,” says Sears. “We really pride ourselves on our controls and efficiencies.” Adding to that complexity is the fact that the longer it takes to deliver aid, the more dire the human need can be. Any time AmeriCares associates can shave off the complicated aid delivery process can translate into lives saved. “It’s really being able to track information consistently that will help us to see where are the bottlenecks and where can we work on improving our processes,” says McDermott. Setting a Standard Productivity and information management improvements were key objectives for AmeriCares when staff began the process of implementing Oracle’s Primavera solution. But before configuring the software, the staff needed to take the time to analyze the systems already in place. According to Greg Loop, manager of database systems at AmeriCares, the organization received guidance from several consultants, including Rich D’Addario, consulting project manager in the Primavera Global Business Unit at Oracle, who was instrumental in shepherding the critical requirements-gathering phase. D’Addario encouraged staff to begin documenting shipping processes by considering the order in which activities occur and which ones are dependent on others to get accomplished. This exercise helped everyone realize that to be more efficient, they needed to keep track of shipments in a more standard way. “The staff didn’t recognize formal project management methodology,” says D’Addario. “But they did understand what the most important things are and that if they go wrong, an entire project can go off course.” Before, if a boatload of supplies was being sent to Haiti and there was a problem somewhere, a lot of time was taken up finding out where the problem was—because staff was not tracking things in a standard way. As a result, even more time was needed to find possible solutions to the problem and alert recipients that the aid might be delayed. “For everyone to put on the project manager hat and standardize the way every single thing is done means that now the whole organization is on the same page as to what needs to occur from the time a hurricane hits Haiti and when a boat pulls in to unload supplies,” says D’Addario. With so much care taken to put a process foundation firmly in place, configuring the Primavera solution was actually quite simple. Specific templates were set up for different types of shipments, and dashboards were implemented to provide executives with clear overviews of every project in the system. AmeriCares’ Loop reports that system planning, refining, and testing, followed by writing up documentation and training, took approximately four months. The system went live in spring 2011 at AmeriCares’ Connecticut headquarters. While the nonprofit has an international presence, with warehouses in Europe and offices in Haiti, India, Japan, and Sri Lanka, most donated medicines come from U.S. entities and are shipped from the U.S. out to the rest of the world. In addition, all shipments are tracked from the U.S. office. AmeriCares doesn’t expect the Primavera system to take months off the shipping time, especially for sea containers. However, any time saved is still important because it will allow aid to be delivered to people more quickly at a lower overall cost. “If we can trim a day or two here or there, that can translate into lives that we’re saving, especially in emergency situations,” says Sears. A Cultural Change Beyond the measurable benefits that come with IT-driven process improvement, AmeriCares management is seeing a change in culture as a result of the Primavera project. One change has been treating every shipment of aid as a project, and everyone involved with facilitating shipments as a project manager. “This is a revolutionary concept for us,” says McDermott. “Before, we were used to thinking we were doing logistics—getting a container from point A to point B without looking at it as one project and really understanding what it meant to manage it.” AmeriCares staff is also happy to report that collaboration within the organization is much more efficient. When someone creates a shipment in the Primavera system, the same shared template is used, which means anyone can log in to the system to see the status of a shipment. Knowledgeable staff can access a shipment project to help troubleshoot a problem. Management can easily check the status of projects across the organization. “Dashboards are really useful,” says McDermott. “Instead of going into the details of each project, you can just see the high-level real-time information at a glance.” The new system is helping team members focus on proactively managing shipments rather than simply reacting when problems occur. For example, when a container is shipped, documents must be included for customs clearance. Now, the shipping template has built-in reminders to prompt team members to ask for copies of these documents from freight forwarders and to follow up with partners to discover if a shipment is on time. In the past, staff may not have worked on securing these documents until they’d been notified a shipment had arrived in-country. Another benefit of capturing and adopting best practices within the Primavera system is that staff training is easier. “Capturing the processes in documented steps and milestones allows us to teach new staff members how to do their jobs faster,” says Sears. “It provides them with the knowledge of their predecessors so they don’t have to keep reinventing the wheel.” With the Primavera system already generating positive results, management is eager to take advantage of advanced capabilities. Loop is working on integrating the company’s proprietary inventory management system with the Primavera system so that when logistics or warehousing operators input data, the information will automatically go into the Primavera system. In the past, this information had to be manually keyed into spreadsheets, often leading to errors. Mining Historical Data Another feature on the horizon for AmeriCares is utilizing Primavera P6 Professional Project Management reporting capabilities. As the system begins to include more historical data, management soon will be able to draw on this information to conduct analysis that has not been possible before and create customized reports. For example, at the beginning of the shipment process, staff will be able to use historical data to more accurately estimate how long the approval process should take for a particular country. This could help ensure that food and medicine with limited shelf lives do not get stuck in customs or used beyond their expiration dates. The historical data in the Primavera system will also help AmeriCares with better planning year to year. The nonprofit’s staff has always put together a plan at the beginning of the year, but this has been very challenging simply because it is impossible to predict disasters. Now, management will be able to look at historical data and see trends and statistics as they set current objectives and prepare for future need. In addition, this historical data will provide AmeriCares management with the ability to review year-end data and compare actual project results with goals set at the beginning of the year—to see if desired outcomes were achieved and if there are areas that need improvement. It’s this type of information that is so valuable to donors. And, according to York, project management software can play a critical role in generating the data to help nonprofits sustain and grow. “It is important to invest in systems to help replicate, expand, and deliver services,” says York. “Project management software can help because it encourages nonprofits to examine program or service changes and how to manage moving forward.” Sears believes that AmeriCares donors will support the return on investment the organization will achieve with the Primavera solution. “It won’t be financial returns, but rather how many more people we can help for a given dollar or how much more quickly we can respond to a need,” says Sears. “I think donors are receptive to such arguments.” And for AmeriCares, it is all about the future and increasing results. The project management environment currently may be quite simple, but IT staff plans to expand the complexity and functionality as the organization grows in its knowledge of project management and the goals it wants to achieve. “As we use the system over time, we’ll continue to refine our best practices and accumulate more data,” says Sears. “It will advance our ability to make better data-driven decisions.”

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  • How to Load Oracle Tables From Hadoop Tutorial (Part 5 - Leveraging Parallelism in OSCH)

    - by Bob Hanckel
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Using OSCH: Beyond Hello World In the previous post we discussed a “Hello World” example for OSCH focusing on the mechanics of getting a toy end-to-end example working. In this post we are going to talk about how to make it work for big data loads. We will explain how to optimize an OSCH external table for load, paying particular attention to Oracle’s DOP (degree of parallelism), the number of external table location files we use, and the number of HDFS files that make up the payload. We will provide some rules that serve as best practices when using OSCH. The assumption is that you have read the previous post and have some end to end OSCH external tables working and now you want to ramp up the size of the loads. Using OSCH External Tables for Access and Loading OSCH external tables are no different from any other Oracle external tables.  They can be used to access HDFS content using Oracle SQL: SELECT * FROM my_hdfs_external_table; or use the same SQL access to load a table in Oracle. INSERT INTO my_oracle_table SELECT * FROM my_hdfs_external_table; To speed up the load time, you will want to control the degree of parallelism (i.e. DOP) and add two SQL hints. ALTER SESSION FORCE PARALLEL DML PARALLEL  8; ALTER SESSION FORCE PARALLEL QUERY PARALLEL 8; INSERT /*+ append pq_distribute(my_oracle_table, none) */ INTO my_oracle_table SELECT * FROM my_hdfs_external_table; There are various ways of either hinting at what level of DOP you want to use.  The ALTER SESSION statements above force the issue assuming you (the user of the session) are allowed to assert the DOP (more on that in the next section).  Alternatively you could embed additional parallel hints directly into the INSERT and SELECT clause respectively. /*+ parallel(my_oracle_table,8) *//*+ parallel(my_hdfs_external_table,8) */ Note that the "append" hint lets you load a target table by reserving space above a given "high watermark" in storage and uses Direct Path load.  In other doesn't try to fill blocks that are already allocated and partially filled. It uses unallocated blocks.  It is an optimized way of loading a table without incurring the typical resource overhead associated with run-of-the-mill inserts.  The "pq_distribute" hint in this context unifies the INSERT and SELECT operators to make data flow during a load more efficient. Finally your target Oracle table should be defined with "NOLOGGING" and "PARALLEL" attributes.   The combination of the "NOLOGGING" and use of the "append" hint disables REDO logging, and its overhead.  The "PARALLEL" clause tells Oracle to try to use parallel execution when operating on the target table. Determine Your DOP It might feel natural to build your datasets in Hadoop, then afterwards figure out how to tune the OSCH external table definition, but you should start backwards. You should focus on Oracle database, specifically the DOP you want to use when loading (or accessing) HDFS content using external tables. The DOP in Oracle controls how many PQ slaves are launched in parallel when executing an external table. Typically the DOP is something you want to Oracle to control transparently, but for loading content from Hadoop with OSCH, it's something that you will want to control. Oracle computes the maximum DOP that can be used by an Oracle user. The maximum value that can be assigned is an integer value typically equal to the number of CPUs on your Oracle instances, times the number of cores per CPU, times the number of Oracle instances. For example, suppose you have a RAC environment with 2 Oracle instances. And suppose that each system has 2 CPUs with 32 cores. The maximum DOP would be 128 (i.e. 2*2*32). In point of fact if you are running on a production system, the maximum DOP you are allowed to use will be restricted by the Oracle DBA. This is because using a system maximum DOP can subsume all system resources on Oracle and starve anything else that is executing. Obviously on a production system where resources need to be shared 24x7, this can’t be allowed to happen. The use cases for being able to run OSCH with a maximum DOP are when you have exclusive access to all the resources on an Oracle system. This can be in situations when your are first seeding tables in a new Oracle database, or there is a time where normal activity in the production database can be safely taken off-line for a few hours to free up resources for a big incremental load. Using OSCH on high end machines (specifically Oracle Exadata and Oracle BDA cabled with Infiniband), this mode of operation can load up to 15TB per hour. The bottom line is that you should first figure out what DOP you will be allowed to run with by talking to the DBAs who manage the production system. You then use that number to derive the number of location files, and (optionally) the number of HDFS data files that you want to generate, assuming that is flexible. Rule 1: Find out the maximum DOP you will be allowed to use with OSCH on the target Oracle system Determining the Number of Location Files Let’s assume that the DBA told you that your maximum DOP was 8. You want the number of location files in your external table to be big enough to utilize all 8 PQ slaves, and you want them to represent equally balanced workloads. Remember location files in OSCH are metadata lists of HDFS files and are created using OSCH’s External Table tool. They also represent the workload size given to an individual Oracle PQ slave (i.e. a PQ slave is given one location file to process at a time, and only it will process the contents of the location file.) Rule 2: The size of the workload of a single location file (and the PQ slave that processes it) is the sum of the content size of the HDFS files it lists For example, if a location file lists 5 HDFS files which are each 100GB in size, the workload size for that location file is 500GB. The number of location files that you generate is something you control by providing a number as input to OSCH’s External Table tool. Rule 3: The number of location files chosen should be a small multiple of the DOP Each location file represents one workload for one PQ slave. So the goal is to keep all slaves busy and try to give them equivalent workloads. Obviously if you run with a DOP of 8 but have 5 location files, only five PQ slaves will have something to do and the other three will have nothing to do and will quietly exit. If you run with 9 location files, then the PQ slaves will pick up the first 8 location files, and assuming they have equal work loads, will finish up about the same time. But the first PQ slave to finish its job will then be rescheduled to process the ninth location file, potentially doubling the end to end processing time. So for this DOP using 8, 16, or 32 location files would be a good idea. Determining the Number of HDFS Files Let’s start with the next rule and then explain it: Rule 4: The number of HDFS files should try to be a multiple of the number of location files and try to be relatively the same size In our running example, the DOP is 8. This means that the number of location files should be a small multiple of 8. Remember that each location file represents a list of unique HDFS files to load, and that the sum of the files listed in each location file is a workload for one Oracle PQ slave. The OSCH External Table tool will look in an HDFS directory for a set of HDFS files to load.  It will generate N number of location files (where N is the value you gave to the tool). It will then try to divvy up the HDFS files and do its best to make sure the workload across location files is as balanced as possible. (The tool uses a greedy algorithm that grabs the biggest HDFS file and delegates it to a particular location file. It then looks for the next biggest file and puts in some other location file, and so on). The tools ability to balance is reduced if HDFS file sizes are grossly out of balance or are too few. For example suppose my DOP is 8 and the number of location files is 8. Suppose I have only 8 HDFS files, where one file is 900GB and the others are 100GB. When the tool tries to balance the load it will be forced to put the singleton 900GB into one location file, and put each of the 100GB files in the 7 remaining location files. The load balance skew is 9 to 1. One PQ slave will be working overtime, while the slacker PQ slaves are off enjoying happy hour. If however the total payload (1600 GB) were broken up into smaller HDFS files, the OSCH External Table tool would have an easier time generating a list where each workload for each location file is relatively the same.  Applying Rule 4 above to our DOP of 8, we could divide the workload into160 files that were approximately 10 GB in size.  For this scenario the OSCH External Table tool would populate each location file with 20 HDFS file references, and all location files would have similar workloads (approximately 200GB per location file.) As a rule, when the OSCH External Table tool has to deal with more and smaller files it will be able to create more balanced loads. How small should HDFS files get? Not so small that the HDFS open and close file overhead starts having a substantial impact. For our performance test system (Exadata/BDA with Infiniband), I compared three OSCH loads of 1 TiB. One load had 128 HDFS files living in 64 location files where each HDFS file was about 8GB. I then did the same load with 12800 files where each HDFS file was about 80MB size. The end to end load time was virtually the same. However when I got ridiculously small (i.e. 128000 files at about 8MB per file), it started to make an impact and slow down the load time. What happens if you break rules 3 or 4 above? Nothing draconian, everything will still function. You just won’t be taking full advantage of the generous DOP that was allocated to you by your friendly DBA. The key point of the rules articulated above is this: if you know that HDFS content is ultimately going to be loaded into Oracle using OSCH, it makes sense to chop them up into the right number of files roughly the same size, derived from the DOP that you expect to use for loading. Next Steps So far we have talked about OLH and OSCH as alternative models for loading. That’s not quite the whole story. They can be used together in a way that provides for more efficient OSCH loads and allows one to be more flexible about scheduling on a Hadoop cluster and an Oracle Database to perform load operations. The next lesson will talk about Oracle Data Pump files generated by OLH, and loaded using OSCH. It will also outline the pros and cons of using various load methods.  This will be followed up with a final tutorial lesson focusing on how to optimize OLH and OSCH for use on Oracle's engineered systems: specifically Exadata and the BDA. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

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  • Using Javascript to call the Azure Blob Storage REST API

    - by user350829
    I'm developing a Flash app that saves files to the Azure Blob Storage API. I've learned that you should use the REST API directly rather than a go-between WCF service as this is the most efficient (using a web role is a bottleneck). The problem is that Flash can't do PUT or DELETE methods over Http and has to use external Javascript. This is not an area that I'm familiar with and need some advice/links to examples of using Javascript to work with the Storage API (I've obviously Googled this to no avail). Is this even possible? The Javascript would be hosted in a web role on the same domain. Many thanks, Ed

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  • How to do RLE (run length encoding) in C# on a byte array?

    - by CuriousCoder
    I am trying to XOR two bitmap files (their byte arrays) to produce a byte array that can be used to change image A into image B or vice versa. I am sending this over the network so I would like to do some basic compression before this happens. Is there a way to do RLE (run length encoding) in C# (using a built-in, or fast reliable 3rd party library) on a byte array for this purpose? Notes: If you are going to suggest an alternative to my approach please keep in mind that the decompression and transformation on the remote machine has to be as quick and efficient as possible.

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  • Linq: Converting flat structure to hierarchical

    - by Stefan Steinegger
    What is the easiest and somewhat efficient way to convert a flat structure: object[][] rawData = new object[][] { { "A1", "B1", "C1" }, { "A1", "B1", "C2" }, { "A2", "B2", "C3" }, { "A2", "B2", "C4" } // .. more }; into a hierarchical structure: class X { public X () { Cs = new List<string>(); } public string A { get; set; } public string B { get; set; } public List<string> Cs { get; private set; } } the result should look like this // pseudo code which describes structure: result = { new X() { A = "A1", B = "B1", Cs = { "C1", "C2" } }, new X() { A = "A2", B = "B2", Cs = { "C3", "C4" } } } Preferably using Linq extension methods. Target class X could be changed (eg. a public setter for the List), only if not possible / useful as it is now.

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  • Creating a constant Dictionary in C#

    - by David Schmitt
    What is the most efficient way to create a constant (never changes at runtime) mapping of strings to ints? I've tried using a const Dictionary, but that didn't work out. I could implement a immutable wrapper with appropriate semantics, but that still doesn't seem totally right. For those who have asked, I'm implementing IDataErrorInfo in a generated class and am looking for a way to make the columnName lookup into my array of descriptors. I wasn't aware (typo when testing! d'oh!) that switch accepts strings, so that's what I'm gonna use. Thanks!

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  • Lazy Load images on Listview in android(Beginner Level)?

    - by Praveen Chandrasekaran
    Hi all, I am working on the listview with the custom adapter. I want to load the images and text view on it. The images are load from the internet urls. I just want to show the images which are visible list item to hte user. I refered the Shelves opensource project example from romainguy, but its to complicated to understand the code. For a beginner level, I just want to know how to handle the tag between the adapter and activity. From the commonsware example I can set the tag on adapter, but can't show the corresponding image at the idle state of the listview. Please help me with your ideas. Sample codes are more understandable. Thanks. EDIT: The combination of Efficient and Slow Adapter in ApiDemos is more helpful to understand.

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  • Drawing a clamped uniform cubic B-spline using Cairo

    - by Tamás
    I have a bunch of coordinates which are the control points of a clamped uniform cubic B-spline on the 2D plane. I would like to draw this curve using Cairo calls (in Python, using Cairo's Python bindings), but as far as I know, Cairo supports Bézier curves only. I also know that the segments of a B-spline between two control points can be drawn using Bézier curves, but I can't find the exact formulae anywhere. Given the coordinates of the control points, how can I derive the control points of the corresponding Bézier curves? Is there any efficient algorithm for that?

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  • Creating a "crossover" function for a genetic algorithm to improve network paths

    - by Dave
    Hi, I'm trying to develop a genetic algorithm that will find the most efficient way to connect a given number of nodes at specified locations. All the nodes on the network must be able to connect to the server node and there must be no cycles within the network. It's basically a tree. I have a function that can measure the "fitness" of any given network layout. What's stopping me is that I can't think of a crossover function that would take 2 network structures (parents) and somehow mix them to create offspring that would meet the above conditions. Any ideas? Clarification: The nodes each have a fixed x,y coordiante position. Only the routes between them can be altered.

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  • Calculated control on subform based on current record

    - by rtochip
    I have the following: main form "customer" from a "customer" table. subform "invoices" with fields "invoice date", "invoice amount" "customer id" etc. from a table "invoices" whenever user clicks or goes to a record in the "invoices" sub form. I would like a "total so far" control to calculate the sum of the "invoices amount" up until the date of the current record being "clicked" or selected. i.e. for customer microsoft with invoices: 1) may 2 09, $150 2) may 3 09, $200 3) may 4 09, $500 If user clicks on record 2), "total so far" should show $350 If user clicks on record 1), "total so far" should show $150 If user clicks on record 3), "total so far" should show $850 Currently, I am using DSum function on an event "OnCurrent" in the subform "invoices" to set the "total so far" value. Is this method slow, inefficient? Any other simpler,cleaner,more elegant,faster, efficient method using ms access features? I want the "invoices" subform to show ALL the invoices for this customer no matter which record is clicked.

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  • Units of measurement conversion logic in C#

    - by EvanRyan
    I am adding a feature to my program in which the user will have the ability to change their unit of measurement at any time, and have the program recalculate their input and output. If the user inputs say, 20lbs for an item, then decides he wants to work in kilograms instead, he can select an option to do so at any time, and the program will recalculate his 20lb input to 9Kg. Then if he decides he'd rather work in ounces, it would convert that 9Kg to 320oz, so on and so forth. What would be the most effective and efficient way to go about this? I've been racking my brain trying to figure out a way to have the correct formula be implemented.

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  • Pandas Dataframe to JSON File with Separate Records

    - by Chris
    I'm attempting to dump data from a Pandas Dataframe into a JSON file to import into MongoDB. The format I require in a file has JSON records on each line of the form: {<column 1>:<value>,<column 2>:<value>,...,<column N>:<value>} df.to_json(,orient='records') gets close to the result but all the records are dumped within a single JSON array. Any thoughts on an efficient way to get this result from a dataframe? UPDATE: The best solution I've come up with is the following: dlist = df.to_dict('records') dlist = [json.dumps(record)+"\n" for record in dlist] open('data.json','w').writelines(dlist)

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  • FNhibernate, GeneratedBy.HiLo, hibernate_unique_key etc.

    - by csetzkorn
    Hi, I have started using the s#arp architecture which uses FNhibernate and GeneratedBy.HiLo to generate primary keys (there is also table hibernate_unique_key). Apparently, this is recommended practise and I would like to stick with this. Now to my problem. I have used NHibernate and hbm mapping quite a bit and usually used identity columns for my primary keys. This allowed me to seed the database using SQL. Can I do this with the aforementioned setup (hibernate_unique_key table etc.). I need to do this as SQL insert is much more efficient than using NHibernate + C# to seed the db with a million entities. Any feedback would be very much appreciated. Thanks. Christian

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