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Can I version dotfiles within a project without merging their history into the main line?
- by istrasci
I'm sure this title is fairly obscure. I'm wondering if there is some way in git to tell it that you want a certain file to use different versions of a file when moving between branches, but to overall be .gitignored from the repository. Here's my scenario: I've got a Flash Builder project (for a Flex app) that I control with git. Flex apps in Flash Builder projects create three files: .actionScriptProperties, .flexProperties, and .project. These files contain lots of local file system references (source folders, output folders, etc.), so naturally we .gitignore them from our repo. Today, I wanted to use a new library in my project, so I made a separate git branch called lib, removed the old version of the library and put in the new one. Unfortunately, this Flex library information gets stored in one of those three dot files (not sure which offhand). So when I had to switch back to the first branch (master) earlier, I was getting compile errors because master was now linked to the new library (which basically negated why I made lib in the first place). So I'm wondering if there's any way for me to continue to .gitignore these files (so my other developers don't get them), but tell git that I want it to use some kind of local "branch version" so I can locally use different versions of the files for different branches.Read the article
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How do I use cookies to store users' recent site history(PHP)?
- by ggfan
I decided to make a recent view box that allows users to see what links they clicked on before. Whenever they click on a posting, the posting's id gets stored in a cookie and displays it in the recent view box. In my ad.php, I have a definerecentview function that stores the posting's id (so I can call it later when trying to get the posting's information such as title, price from the database) in a cookie. How do I create a cookie array for this? **EXAMPLE:** user clicks on ad.php?posting_id='200' //this is in the ad.php function definerecentview() { $posting_id=$_GET['posting_id']; //this adds 30 days to the current time $Month = 2592000 + time(); $i=1; if (isset($posting_id)){ //lost here for($i=1,$i< ???,$i++){ setcookie("recentviewitem[$i]", $posting_id, $Month); } } } function displayrecentviews() { echo "<div class='recentviews'>"; echo "Recent Views"; if (isset($_COOKIE['recentviewitem'])) { foreach ($_COOKIE['recentviewitem'] as $name => $value) { echo "$name : $value <br />\n"; //right now just shows the posting_id } } echo "</div>"; } How do I use a for loop or foreach loop to make it that whenever a user clicks on an ad, it makes an array in the cookie? So it would be like.. 1. clicks on ad.php?posting_id=200 --- setcookie("recentviewitem[1]",200,$month); 2. clicks on ad.php?posting_id=201 --- setcookie("recentviewitem[2]",201,$month); 3. clicks on ad.php?posting_id=202 --- setcookie("recentviewitem[3]",202,$month); Then in the displayrecentitem function, I just echo however many cookies were set? I'm just totally lost in creating a for loop that sets the cookies. any help would be appreciatedRead the article
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Parallel programming, are we not learning from history again?
- by mezmo
I started programming because I was a hardware guy that got bored, I thought the problems being solved in the software side of things were much more interesting than those in hardware. At that time, most of the electrical buses I dealt with were serial, some moving data as fast as 1.5 megabit!! ;) Over the years these evolved into parallel buses in order to speed communication up, after all, transferring 8/16/32/64, whatever bits at a time incredibly speeds up the transfer. Well, our ability to create and detect state changes got faster and faster, to the point where we could push data so fast that interference between parallel traces or cable wires made cleaning the signal too expensive to continue, and we still got reasonable performance from serial interfaces, heck some graphics interfaces are even happening over USB for a while now. I think I'm seeing a like trend in software now, our processors were getting faster and faster, so we got good at building "serial" software. Now we've hit a speed bump in raw processor speed, so we're adding cores, or "traces" to the mix, and spending a lot of time and effort on learning how to properly use those. But I'm also seeing what I feel are advances in things like optical switching and even quantum computing that could take us far more quickly that I was expecting back to the point where "serial programming" again makes the most sense. What are your thoughts?Read the article
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How to define a history chart in crystal reports .net (2008)?
- by hp
Hi, I want to display a Bar Chart in a Report that shows the sum of a measure grouped by month for the last 24 month. The months that do not have any tuples do not show up in the graph. I do not want that. I want exactly 24 groups/bars that are 0 if there are no tuples. What is the best way to do this? thanksRead the article
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Are compound command's second and subsequent lines not effected by HISTCONTROL in bash?
- by UniMouS
When consulting bash's man page, it read this sentence about bash history: The second and subsequent lines of a multi-line compound command are not tested, and are added to the history regardless of the value of HISTCONTROL. But I have tried this: $ HISTCONTROL=ignorespace $ if [ -f /var/log/messages ] > then > echo "/var/log/message exists." > fi $ history | tail -2 18 HISTCONTROL=ignorespace 19 history | tail -2 Note that the if is leaded by a space. Why the second line of this if compound command still not appear in the history?Read the article
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Backbone.js: How to utilize router.navigate to manipulate browser history?
- by Xavier_Ex
I am writing something like a registration process containing several steps, and I want to make it a single-page like system so after some studying Backbone.js is my choice. Every time the user completes the current step they will click on a NEXT button I create and I use the router.navigate method to update the url, as well as loading the content of the next page and doing some fancy transition with javascript. Result is, URL is updated which the page is not refreshed, giving a smooth user experience. However, when the user clicks on the back button of the browser, the URL gets updated to that of a previous step, but the content stays the same. My question is through what way I can capture such an event and currently load the content of the previous step and present that to the user? Or even better, can I rely on browser cache to load that previously loaded page? EDIT: in particular, I'm trying something like mentioned in this article.Read the article
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Pthread - setting scheduler parameters
- by Andna
I wanted to use read-writer locks from pthread library in a way, that writers have priority over readers. I read in my man pages that If the Thread Execution Scheduling option is supported, and the threads involved in the lock are executing with the scheduling policies SCHED_FIFO or SCHED_RR, the calling thread shall not acquire the lock if a writer holds the lock or if writers of higher or equal priority are blocked on the lock; otherwise, the calling thread shall acquire the lock. so I wrote small function that sets up thread scheduling options. void thread_set_up(int _thread) { struct sched_param *_param=malloc(sizeof (struct sched_param)); int *c=malloc(sizeof(int)); *c=sched_get_priority_min(SCHED_FIFO)+1; _param->__sched_priority=*c; long *a=malloc(sizeof(long)); *a=syscall(SYS_gettid); int *b=malloc(sizeof(int)); *b=SCHED_FIFO; if (pthread_setschedparam(*a,*b,_param) == -1) { //depending on which thread calls this functions, few thing can happen if (_thread == MAIN_THREAD) client_cleanup(); else if (_thread==ACCEPT_THREAD) { pthread_kill(params.main_thread_id,SIGINT); pthread_exit(NULL); } } } sorry for those a,b,c but I tried to malloc everything, still I get SIGSEGV on the call to pthread_setschedparam, I am wondering why?Read the article
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How to migrate a codebase from one svn repo to another preserving history?
- by chotchki
I have a branch in a badly structured svn repo that needs to be stripped out and moved to another svn repository. (I'm trying to clean it up some). If I do an 'svn log' and not stop on copy/rename I can see all 3427 commits that I care about. Is there some way to dump the revisions out, short of writing some major scripts? I would follow the advice in this question but this branch has been moved all over the place and I would like to preserve the moves as well. Any ideas?Read the article
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Combining Scrum, TFS2010 and Email to keep everyone in the loop
- by Martin Hinshelwood
Often you will receive rich information from your Product Owner (Customer) about tasks. That information can be in the form of Word documents, HTML Emails and Pictures, but you generally receive them in the context of an Email. You need to keep these so your Team can refer to it later, and so you can send a “done” when the task has been completed. This preserves the “history” of the task and allows you to keep relevant partied included in any future conversation. At SSW we keep the original email so that we can reply Done and delete the email. But keeping it in your email does not help other members of the team if they complete the task and need to send the “done”. Worse yet, the description field in Team Foundation Server 2010 (TFS 2010) does not support HTML and images, nor does the default task template support an “interested parties” or CC field. You can attach this content manually, but it can be time consuming. Figure: Description only supports plain text, and History supports HTML with no images What should we do? At SSW we always follow the rules, and it just so happened that we have rules to both achieve this, and to make it easier. You should follow the existing Rules to Better Project Management and attach the email to your task so you can refer to and reply to it later when you close the task: Do you know what Outlook add-ins you need? Describe the work item request in an email Use Outlook Add-in to move the email to a TFS Work Item When replying to an email with “done” you should follow: Do you update Team Companion template, so the email "subject" doesn't change? Do you update Team Companion template, so you can generate a proper "done" mail? Following these simple rules will help your Product Owner understand you better, and allow your team to more effectively collaborate with each other. An added bonus is that as we are keeping the email history in sync with TFS. When you “reply all” to the email all of the interested partied to the Task are also included. This notified those that may have been blocked by your task to keep up to date with its status. This has been published as Do you know to ensure that relevant emails are attached to tasks in our Rules to Better Scrum using TFS. What could we do better? I would like to see this process automated so that we capture the information correctly in the task without the need to use email. This would require a change to the process template in Team Foundation Server to add an “Interested Parties” field. Each reply to the email would need to be automatically processed into a Work Item. This could be done by adding a task identifier as the first item in the “Relates to” email header, and copying in an email address that you watch. This would then parse out the relevant information and add the new message to the history, update the “Interested parties” field and attach the Images. Upon reflection, it may even be possible, but more difficult to do this using ONLY the History field and including some of the header information in there to the build a done email with history. This would not currently deal with email “forks” well, but I think it would be adequate for our needs. It would be nice if we could find time to implement this, but currently it is but a pipe dream. Maybe Microsoft could implement something in the next version of Team Foundation Server, and in the mean time we have a process that works well. Technorati Tags: Scrum,SSW Rules,TFS 2010,TFS 2008Read the article
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iis7 compress dynamic content from custom handler
- by Malloc
I am having trouble getting dynamic content coming from a custom handler to be compressed by IIS 7. Our handler spits out json data (Content-Type: application/json; charset=utf-8) and responds to url that looks like: domain.com/example.mal/OperationName?Param1=Val1&Param2=Val2 In IIS 6, all we had to do was put the edit the MetaBase.xml and in the IIsCompressionScheme element make sure that the HcScriptFileExtensions attribute had the custom extension 'mal' included in it. Static and Dynamic compression is turned out at the server and website level. I can confirm that normal .aspx pages are compressed correctly. The only content I cannot have compressed is the content coming from the custom handler. I have tried the following configs with no success: <handlers> <add name="MyJsonService" verb="GET,POST" path="*.mal" type="Library.Web.HttpHandlers.MyJsonServiceHandlerFactory, Library.Web" /> </handlers> <httpCompression> <dynamicTypes> <add mimeType="application/json" enabled="true" /> </dynamicTypes> </httpCompression> _ <httpCompression> <dynamicTypes> <add mimeType="application/*" enabled="true" /> </dynamicTypes> </httpCompression> _ <staticContent> <mimeMap fileExtension=".mal" mimeType="application/json" /> </staticContent> <httpCompression> <dynamicTypes> <add mimeType="application/*" enabled="true" /> </dynamicTypes> </httpCompression> Thanks in advance for the help.Read the article
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Memory read/write access efficiency
- by wolfPack88
I've heard conflicting information from different sources, and I'm not really sure which one to believe. As such, I'll post what I understand and ask for corrections. Let's say I want to use a 2D matrix. There are three ways that I can do this (at least that I know of). 1: int i; char **matrix; matrix = malloc(50 * sizeof(char *)); for(i = 0; i < 50; i++) matrix[i] = malloc(50); 2: int i; int rowSize = 50; int pointerSize = 50 * sizeof(char *); int dataSize = 50 * 50; char **matrix; matrix = malloc(dataSize + pointerSize); char *pData = matrix + pointerSize - rowSize; for(i = 0; i < 50; i++) { pData += rowSize; matrix[i] = pData; } 3: //instead of accessing matrix[i][j] here, we would access matrix[i * 50 + j] char *matrix = malloc(50 * 50); In terms of memory usage, my understanding is that 3 is the most efficient, 2 is next, and 1 is least efficient, for the reasons below: 3: There is only one pointer and one allocation, and therefore, minimal overhead. 2: Once again, there is only one allocation, but there are now 51 pointers. This means there is 50 * sizeof(char *) more overhead. 1: There are 51 allocations and 51 pointers, causing the most overhead of all options. In terms of performance, once again my understanding is that 3 is the most efficient, 2 is next, and 1 is least efficient. Reasons being: 3: Only one memory access is needed. We will have to do a multiplication and an addition as opposed to two additions (as in the case of a pointer to a pointer), but memory access is slow enough that this doesn't matter. 2: We need two memory accesses; once to get a char *, and then to the appropriate char. Only two additions are performed here (once to get to the correct char * pointer from the original memory location, and once to get to the correct char variable from wherever the char * points to), so multiplication (which is slower than addition) is not required. However, on modern CPUs, multiplication is faster than memory access, so this point is moot. 1: Same issues as 2, but now the memory isn't contiguous. This causes cache misses and extra page table lookups, making it the least efficient of the lot. First and foremost: Is this correct? Second: Is there an option 4 that I am missing that would be even more efficient?Read the article
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how to rollback/undo yum update on fedora after messing the fedora versions
- by misteryes
I want to install texlive on my fedora 16 laptop with the following procedure: # yum remove tex-* texlive-* # cat > /etc/yum.repos.d/texlive.repo <<EOF [texlive] name=texlive baseurl=http://jnovy.fedorapeople.org/texlive/2012/packages.f17/ enabled=1 gpgcheck=0 EOF # yum update; # yum install texlive after yum update, I notice that my laptop is fedora 16, while I used 2012/packages.fc17/ so I modify /etc/yum.repos.d/texlive.repo to use 2011/packages.fc16 and do yum update again however, there are many errors [root@kitty esolve]# yum update Loaded plugins: auto-update-debuginfo, langpacks, presto, refresh-packagekit http://repos.fedorapeople.org/repos/leigh123linux/cinnamon/fedora-16/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found : http://repos.fedorapeople.org/repos/leigh123linux/cinnamon/fedora-16/x86_64/repodata/repomd.xml Trying other mirror. Setting up Update Process Resolving Dependencies --> Running transaction check ---> Package dvipng.x86_64 0:1.14-1.fc15 will be obsoleted ---> Package kpathsea.x86_64 0:2007-66.fc16 will be obsoleted --> Processing Dependency: libkpathsea.so.4()(64bit) for package: evince-dvi-3.2.1-2.fc16.x86_64 ---> Package mkvtoolnix.x86_64 0:5.8.0-1 will be updated ---> Package mkvtoolnix.x86_64 0:6.3.0-1 will be an update ---> Package nautilus-dropbox.x86_64 0:1.4.0-1.fc10 will be updated ---> Package nautilus-dropbox.x86_64 0:1.6.0-1.fc10 will be an update ---> Package texlive-dvipng-bin.x86_64 2:svn26509.0-19.20130317_r29408.fc17 will be obsoleting --> Processing Dependency: texlive-kpathsea-lib = 2:2012-19.20130317_r29408.fc17 for package: 2:texlive-dvipng-bin-svn26509.0-19.20130317_r29408.fc17.x86_64 --> Processing Dependency: texlive-base for package: 2:texlive-dvipng-bin-svn26509.0-19.20130317_r29408.fc17.x86_64 --> Processing Dependency: tex-dvipng for package: 2:texlive-dvipng-bin-svn26509.0-19.20130317_r29408.fc17.x86_64 --> Processing Dependency: libpng15.so.15()(64bit) for package: 2:texlive-dvipng-bin-svn26509.0-19.20130317_r29408.fc17.x86_64 --> Processing Dependency: libkpathsea.so.6()(64bit) for package: 2:texlive-dvipng-bin-svn26509.0-19.20130317_r29408.fc17.x86_64 ---> Package texlive-kpathsea.noarch 2:svn28792.0-19.fc17 will be obsoleting --> Processing Dependency: texlive-kpathsea-bin for package: 2:texlive-kpathsea-svn28792.0-19.fc17.noarch --> Running transaction check ---> Package kpathsea.x86_64 0:2007-66.fc16 will be obsoleted --> Processing Dependency: libkpathsea.so.4()(64bit) for package: evince-dvi-3.2.1-2.fc16.x86_64 ---> Package texlive-base.noarch 2:2012-19.20130317_r29408.fc17 will be installed ---> Package texlive-dvipng.noarch 2:svn26689.1.14-19.fc17 will be installed ---> Package texlive-dvipng-bin.x86_64 2:svn26509.0-19.20130317_r29408.fc17 will be obsoleting --> Processing Dependency: libpng15.so.15()(64bit) for package: 2:texlive-dvipng-bin-svn26509.0-19.20130317_r29408.fc17.x86_64 ---> Package texlive-kpathsea-bin.x86_64 2:svn27347.0-19.20130317_r29408.fc17 will be installed ---> Package texlive-kpathsea-lib.x86_64 2:2012-19.20130317_r29408.fc17 will be installed --> Finished Dependency Resolution Error: Package: evince-dvi-3.2.1-2.fc16.x86_64 (@fedora) Requires: libkpathsea.so.4()(64bit) Removing: kpathsea-2007-66.fc16.x86_64 (@so-updates) libkpathsea.so.4()(64bit) Obsoleted By: 2:texlive-kpathsea-svn28792.0-19.fc17.noarch (texlive) Not found Error: Package: 2:texlive-dvipng-bin-svn26509.0-19.20130317_r29408.fc17.x86_64 (texlive) Requires: libpng15.so.15()(64bit) You could try using --skip-broken to work around the problem You could try running: rpm -Va --nofiles --nodigest and when I do yum install texlive, it simply tries to install the f17 version, which failed. what Can I do to install f16 version? how can I undo yum update with 2012/packages.f17/ I tried yum history, and for today's history, I only have Loaded plugins: auto-update-debuginfo, langpacks, presto, refresh-packagekit ID | Login user | Date and time | Action(s) | Altered ------------------------------------------------------------------------------- 124 | esolve ... <esolve> | 2013-09-12 18:35 | Erase | 24 123 | root <root> | 2013-08-23 11:08 | Update | 1 122 | root <root> | 2013-08-21 14:13 | Update | 1 < 121 | esolve ... <esolve> | 2013-05-31 15:36 | Install | 1 > 120 | root <root> | 2013-05-29 15:13 | Install | 1 < 119 | root <root> | 2013-04-18 13:13 | Update | 1 >< which seems not related to yum update the history results: 1003 yum update 1004 vim 1005 vim /etc/yum.repos.d/texlive.repo 1006 yum update 1007 yum install texlive 1008 vim /etc/yum.repos.d/texlive.repo 1009 clear 1010 yum history 1011 yum history list 1012 vim 1013 vim /etc/yum.repos.d/texlive.repo 1014 yum history list 1015 history also I tried yum history undo 124 but it failed! [root@kitty esolve]# yum history undo 124 Loaded plugins: auto-update-debuginfo, langpacks, presto, refresh-packagekit http://repos.fedorapeople.org/repos/leigh123linux/cinnamon/fedora-16/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found : http://repos.fedorapeople.org/repos/leigh123linux/cinnamon/fedora-16/x86_64/repodata/repomd.xml Trying other mirror. Undoing transaction 124, from Thu Sep 12 18:35:31 2013 Erase R-2.14.1-1.fc16.x86_64 ? Erase R-core-2.14.1-1.fc16.x86_64 ? Erase R-devel-2.14.1-1.fc16.x86_64 ? Erase a2ps-4.14-12.fc15.x86_64 ? Erase docbook-utils-pdf-0.6.14-29.fc16.noarch ? Erase html2ps-1.0-0.7.b7.fc15.noarch ? Erase jadetex-3.13-10.fc15.noarch ? Erase kile-2.1.1-1.fc16.x86_64 ? Erase linuxdoc-tools-0.9.66-9.fc15.x86_64 ? Erase tetex-dvipost-1.1-12.fc15.x86_64 ? Erase tex-cm-lgc-0.5-18.fc15.noarch ? Erase tex-preview-11.86-6.fc16.noarch ? Erase texinfo-tex-4.13a-15.fc15.x86_64 ? Erase texlive-2007-66.fc16.x86_64 ? Erase texlive-dvips-2007-66.fc16.x86_64 ? Erase texlive-latex-2007-66.fc16.x86_64 ? Erase texlive-texmf-2007-40.fc16.noarch ? Erase texlive-texmf-dvips-2007-40.fc16.noarch ? Erase texlive-texmf-fonts-2007-40.fc16.noarch ? Erase texlive-texmf-latex-2007-40.fc16.noarch ? Erase texlive-utils-2007-66.fc16.x86_64 ? Erase texmaker-1:3.2.2-1.fc16.x86_64 ? Erase texmf-RR-Inria-4.11-inria.0.noarch ? Erase xdvik-22.84.14-9.fc15.x86_64 ? Error: No package(s) available to installRead the article
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How to bind up arrow in ~/.inputrc (readline) for vim insert mode?
- by Pawel Goscicki
When in Readline apps with vim mode enabled in ~/.inputrc (set editing-mode vi) is there a way to bind the up arrow key? To previous history, for example. It seems I have to press ESC key first, only then it works. Here's my attempt at making it work (~/.inputrc): $if mode=vi # INSERT MODE set keymap vi-insert "\e[A": history-search-backward # up-arrow "\e[B": history-search-forward # down-arrow Also note, that when I press Ctrl+v and then <Up>, it prints ^[[A.Read the article
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Oracle Develop Newbies
- by Cassandra Clark
tweetmeme_url = 'http://blogs.oracle.com/develop/2010/06/oracle_develop_newbies.html'; Share .FBConnectButton_Small{background-position:-5px -232px !important;border-left:1px solid #1A356E;} .FBConnectButton_Text{margin-left:12px !important ;padding:2px 3px 3px !important;} There are a number of us in the Oracle Technology Network team that came over from the Sun acquisition so we are true Oracle Develop "newbies." We are boning up on Oracle history and thought it would be fun to test your knowledge too. Below are a few Oracle history questions. Post your answers in the comment section of the blog and if you answer all questions correctly you will be listed in the next post as an "Oracle Genius". Feel free to turn the tables on your fellow blog readers by posting your own Oracle history questions. If you stump the community we'll add your question to our next post as well. Oracle History Quiz - In 2003, what Applications rival company did Oracle acquire?In which year was JDeveloper first released?In what language was Oracle v 1.0 written?What Oracle program is designed to recognize and reward members of the Oracle Technology and Applications communities for their contributions back to the Oracle community?What party event draws in nearly 4,000 attendees every year during Oracle OpenWorld, Oracle Develop and now JavaOne?See you in September!Read the article
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SQL SERVER – Weekly Series – Memory Lane – #007
- by pinaldave
Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 Find Stored Procedure Related to Table in Database – Search in All Stored Procedure In 2006 I wrote a small script which will help user find all the Stored Procedures (SP) which are related to one or more specific tables. This was quite a popular script however, in SQL Server 2012 the same can be achieved using new DMV sys.sql-expression_dependencies. I recently blogged about it over Find Referenced or Referencing Object in SQL Server using sys.sql_expression_dependencies. 2007 SQL SERVER – Versions, CodeNames, Year of Release 1993 – SQL Server 4.21 for Windows NT 1995 – SQL Server 6.0, codenamed SQL95 1996 – SQL Server 6.5, codenamed Hydra 1999 – SQL Server 7.0, codenamed Sphinx 1999 – SQL Server 7.0 OLAP, codenamed Plato 2000 – SQL Server 2000 32-bit, codenamed Shiloh (version 8.0) 2003 – SQL Server 2000 64-bit, codenamed Liberty 2005 – SQL Server 2005, codenamed Yukon (version 9.0) 2008 – SQL Server 2008, codenamed Katmai (version 10.0) 2011 – SQL Server 2008, codenamed Denali (version 11.0) Search String in Stored Procedure Searching sting in the stored procedure is one of the most frequent task developer do. They might be searching for a table, view or any other details. I have written a script to do the same in SQL Server 2000 and SQL Server 2005. This is worth bookmarking blog post. There is an alternative way to do the same as well here is the example. 2008 SQL SERVER – Refresh Database Using T-SQL NO! Some of the questions have a single answer NO! You may want to read the question in the original blog post. I had a great time saying No! SQL SERVER – Delete Backup History – Cleanup Backup History SQL Server stores history of all the taken backup forever. History of all the backup is stored in the msdb database. Many times older history is no more required. Following Stored Procedure can be executed with a parameter which takes days of history to keep. In the following example 30 is passed to keep a history of month. 2009 Stored Procedure are Compiled on First Run – SP taking Longer to Run First Time Is stored procedure pre-compiled? Why the Stored Procedure takes a long time to run for the first time? This is a very common questions often discussed by developers and DBAs. There is an absolutely definite answer but the question has been discussed forever. There is a misconception that stored procedures are pre-compiled. They are not pre-compiled, but compiled only during the first run. For every subsequent runs, it is for sure pre-compiled. Read the entire article for example and demonstration. Removing Key Lookup – Seek Predicate – Predicate – An Interesting Observation Related to Datatypes This is one of the most important performance tuning lesson on my blog. I suggest this weekend you spend time reading them and let me know what you think about the concepts which I have demonstrated in the four part series. Part 1 | Part 2 | Part 3 | Part 4 Seek Predicate is the operation that describes the b-tree portion of the Seek. Predicate is the operation that describes the additional filter using non-key columns. Based on the description, it is very clear that Seek Predicate is better than Predicate as it searches indexes whereas in Predicate, the search is on non-key columns – which implies that the search is on the data in page files itself. Policy Based Management – Create, Evaluate and Fix Policies This article will cover the most spectacular feature of SQL Server – Policy-based management and how the configuration of SQL Server with policy-based management architecture can make a powerful difference. Policy based management is loaded with several advantages. It can help you implement various policies for reliable configuration of the system. It also provides additional administration assistance to DBAs and helps them effortlessly manage various tasks of SQL Server across the enterprise. 2010 Recycle Error Log – Create New Log file without Server Restart Once I observed a DBA to restaring the SQL Server when he needed new error log file. This was funny and sad both at the same time. There is no need to restart the server to create a new log file or recycle the log file. You can run sp_cycle_errorlog and achieve the same result. Get Database Backup History for a Single Database Simple but effective script! Reducing CXPACKET Wait Stats for High Transactional Database The subject is very complex and I have done my best to simplify the concept. In simpler words, when a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. Threads which came first have to wait for the slower thread to finish. The Wait by a specific completed thread is called CXPACKET Wait Stat. Information Related to DATETIME and DATETIME2 There are quite a lot of confusion with DATETIME and DATETIME2. DATETIME2 is also one of the underutilized datatype of SQL Server. In this blog post I have written a follow up of the my earlier datetime series where I clarify a few of the concepts related to datetime. Difference Between GETDATE and SYSDATETIME Difference Between DATETIME and DATETIME2 – WITH GETDATE Difference Between DATETIME and DATETIME2 2011 Introduction to CUME_DIST – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function CUME_DIST(). This function provides cumulative distribution value. It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. Introduction to FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical functions FIRST_VALUE() and LAST_VALUE(). This function returns first and last value from the list. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. OVER clause with FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 – ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING “Don’t you think there is bug in your first example where FIRST_VALUE is remain same but the LAST_VALUE is changing every line. I think the LAST_VALUE should be the highest value in the windows or set of result.” Puzzle – Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY You can see that row number 2, 3, 4, and 5 has same SalesOrderID = 43667. The FIRST_VALUE is 78 and LAST_VALUE is 77. Now if these function was working on maximum and minimum value they should have given answer as 77 and 80 respectively instead of 78 and 77. Also the value of FIRST_VALUE is greater than LAST_VALUE 77. Why? Explain in detail. Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function LEAD() and LAG(). This functions accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. A Real Story of Book Getting ‘Out of Stock’ to A 25% Discount Story Available Our book was out of stock in 48 hours of it was arrived in stock! We got call from the online store with a request for more copies within 12 hours. But we had printed only as many as we had sent them. There were no extra copies. We finally talked to the printer to get more copies. However, due to festivals and holidays the copies could not be shipped to the online retailer for two days. We knew for sure that they were going to be out of the book for 48 hours. This is the story of how we overcame that situation! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, TechnologyRead the article
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What is the best approach for inline code comments?
- by d1egoaz
We are doing some refactoring to a 20 years old legacy codebase, and I'm having a discussion with my colleague about the comments format in the code (plsql, java). There is no a default format for comments, but in most cases people do something like this in the comment: // date (year, year-month, yyyy-mm-dd, dd/mm/yyyy), (author id, author name, author nickname) and comment the proposed format for future and past comments that I want is: // {yyyy-mm-dd}, unique_author_company_id, comment My colleague says that we only need the comment, and must reformat all past and future comments to this format: // comment My arguments: I say for maintenance reasons, it's important to know when and who did a change (even this information is in the SCM). The code is living, and for that reason has a history. Because without the change dates it's impossible to know when a change was introduced without open the SCM tool and search in the long object history. because the author is very important, a change of authors is more credible than a change of authory Agility reasons, no need to open and navigate through the SCM tool people would be more afraid to change something that someone did 15 years ago, than something that was recently created or changed. etc. My colleague's arguments: The history is in the SCM Developers must not be aware of the history of the code directly in the code Packages gets 15k lines long and unstructured comments make these packages harder to understand What do you think is the best approach? Or do you have a better approach to solve this problem?Read the article
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Reformatting and version control
- by l0b0
Code formatting matters. Even indentation matters. And consistency is more important than minor improvements. But projects usually don't have a clear, complete, verifiable and enforced style guide from day 1, and major improvements may arrive any day. Maybe you find that SELECT id, name, address FROM persons JOIN addresses ON persons.id = addresses.person_id; could be better written as / is better written than SELECT persons.id, persons.name, addresses.address FROM persons JOIN addresses ON persons.id = addresses.person_id; while working on adding more columns to the query. Maybe this is the most complex of all four queries in your code, or a trivial query among thousands. No matter how difficult the transition, you decide it's worth it. But how do you track code changes across major formatting changes? You could just give up and say "this is the point where we start again", or you could reformat all queries in the entire repository history. If you're using a distributed version control system like Git you can revert to the first commit ever, and reformat your way from there to the current state. But it's a lot of work, and everyone else would have to pause work (or be prepared for the mother of all merges) while it's going on. Is there a better way to change history which gives the best of all results: Same style in all commits Minimal merge work ? To clarify, this is not about best practices when starting the project, but rather what should be done when a large refactoring has been deemed a Good Thing™ but you still want a traceable history? Never rewriting history is great if it's the only way to ensure that your versions always work the same, but what about the developer benefits of a clean rewrite? Especially if you have ways (tests, syntax definitions or an identical binary after compilation) to ensure that the rewritten version works exactly the same way as the original?Read the article
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Storing revisions of a document
- by dev.e.loper
This is a follow up question to my original question. I'm thinking of going with generating diffs and storing those diffs in the database 'History' table. I'm using diff-match-patch library to generate what is called a 'patch'. On every save, I compare previous and new version and generate this patch. The patch could be used to generate a document at specific point in time. My dilemma is how to store this data. Should I: a Insert a new database record for every patch? b. Store these patches in javascript array and store that array in history table. So there is only one db History record for document with an array of all the patches. Concerns with: a. Too many db records generated. Will be slow and CPU intensive to query. b. Only one record. If record is somehow corrupted/deleted. Entire revision history is gone. I'm looking for suggestions, concerns with either approach.Read the article
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Core Data error when assigning variable with one-to-one relationship
- by Hoang Pham
I tried to assign a managed object (C) with its property another managed object (B) (a one-to-one relationship) in which this other managed object (B) has a to-many relationship with one other managed object (A). There is an error from this assignment in which I copied as follows: #0 0x020e53a7 in ___forwarding___ #1 0x020c16c2 in __forwarding_prep_0___ #2 0x02078988 in CFRetain #3 0x0207a728 in CFSetAddValue #4 0x020c2fb2 in CFSetCreate #5 0x01e51ce8 in -[_NSFaultingMutableSet copyWithZone:] #6 0x020afcca in -[NSObject copy] #7 0x01e50d22 in -[NSManagedObject(_NSInternalMethods) _newPropertiesForRetainedTypes:andCopiedTypes:preserveFaults:] #8 0x01e51aa0 in -[NSManagedObject(_NSInternalMethods) _newAllPropertiesWithRelationshipFaultsIntact__] #9 0x01e519b4 in -[NSManagedObjectContext(_NSInternalChangeProcessing) _establishEventSnapshotsForObject:] #10 0x01e51866 in _PFFastMOCObjectWillChange #11 0x01e516c5 in _PF_ManagedObject_WillChangeValueForKeyIndex #12 0x01e51525 in _sharedIMPL_setvfk_core #13 0x01e51483 in _PF_Handler_Public_SetProperty #14 0x01e546d1 in -[NSManagedObject(_NSInternalMethods) _didChangeValue:forRelationship:named:withInverse:] #15 0x0030ec1e in NSKVONotify #16 0x002aae2a in -[NSObject(NSKeyValueObserverNotification) didChangeValueForKey:] #17 0x01e5212f in _PF_ManagedObject_DidChangeValueForKeyIndex #18 0x01e515b1 in _sharedIMPL_setvfk_core #19 0x01e55827 in _svfk_5 I don't understand very well what the exact description of this error is. Can someone explain to me what it is and how to solve this one. Note that all other assignments in which the managed object B does not have any A items do not raise this error. ObjectC *objectC = [NSEntityDescription insertNewObjectForEntityForName:@"ObjectC" inManagedObjectContext:managedObjectContext]; objectC.objectB = objectB; Thank you in advance. I added some more NSZombieEnabled/MallocStackLogging generated log: 2010-05-18 17:28:05.327 Foo[2069:207] *** -[CFSet retain]: message sent to deallocated instance 0x800c880 (gdb) shell malloc_history 207 0x800c880 malloc_history cannot examine process 207 because the process does not exist. (gdb) shell malloc_history 2069 0x800c880 ALLOC 0x800c880-0x800c884 [size=5]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlIOParseDTD | _endElementNs | -[Parser parser:didEndElement:namespaceURI:qualifiedName:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | asl_set_query | strdup | malloc | malloc_zone_malloc ---- FREE 0x800c880-0x800c884 [size=5]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlIOParseDTD | _endElementNs | -[Parser parser:didEndElement:namespaceURI:qualifiedName:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | asl_free | free ALLOC 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | asl_set_query | asprintf | malloc | malloc_zone_malloc ---- FREE 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | asl_set_query | free ALLOC 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | asprintf | malloc | malloc_zone_malloc ---- FREE 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | free ALLOC 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | asprintf | malloc | malloc_zone_malloc ---- FREE 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | free ALLOC 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | asprintf | malloc | malloc_zone_malloc ---- FREE 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | free ALLOC 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | asprintf | malloc | malloc_zone_malloc ---- FREE 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | free ALLOC 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | asprintf | malloc | malloc_zone_malloc ---- FREE 0x800c860-0x800c8df [size=128]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlParseCharData | _characters | -[Parser parser:foundCharacters:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | asl_send | _asl_send_level_message | free ALLOC 0x800c700-0x800c893 [size=404]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlIOParseDTD | _startElementNs | -[Parser parser:didStartElement:namespaceURI:qualifiedName:attributes:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | CFCalendarDecomposeAbsoluteTime | _CFCalendarDecomposeAbsoluteTimeV | __CFCalendarSetupCal | __CFCalendarCreateUCalendar | ucal_open | icu::Calendar::createInstance(icu::TimeZone*, icu::Locale const&, UErrorCode&) | malloc | malloc_zone_malloc ---- FREE 0x800c700-0x800c893 [size=404]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlIOParseDTD | _startElementNs | -[Parser parser:didStartElement:namespaceURI:qualifiedName:attributes:] | NSLog | NSLogv | _CFLogvEx | __CFLogCString | _CFRelease | free ALLOC 0x800c880-0x800c8c7 [size=72]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __NSFireDelayedPerform | -[Step2ViewController downloadData] | -[Parser downloadVariantsWithPin:forTerminal:] | -[Parser parseByNSXMLParser:] | -[NSXMLParser parse] | xmlParseChunk | xmlIOParseDTD | _startElementNs | -[Parser parser:didStartElement:namespaceURI:qualifiedName:attributes:] | +[NSEntityDescription insertNewObjectForEntityForName:inManagedObjectContext:] | +[NSManagedObject(_PFDynamicAccessorsAndPropertySupport) allocWithEntity:] | _PFAllocateObject | malloc_zone_calloc ---- FREE 0x800c880-0x800c8c7 [size=72]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __CFRunLoopDoObservers | _performRunLoopAction | -[_PFManagedObjectReferenceQueue _processReferenceQueue:] | _PFDeallocateObject | malloc_zone_free ALLOC 0x800c880-0x800c8a7 [size=40]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __CFRunLoopDoObservers | CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) | CA::Transaction::commit() | CA::Context::commit_transaction(CA::Transaction*) | CALayerDisplayIfNeeded | -[TileLayer display] | -[CALayer _display] | CABackingStoreUpdate | backing_callback(CGContext*, void*) | WebCore::TiledSurface::drawLayer(CALayer*, CGContext*) | WKWindowDrawRect | WKViewDisplayRect | _WKViewDraw(CGContext*, WKView*, CGRect) | _WKViewDraw(CGContext*, WKView*, CGRect) | _WKViewDraw(CGContext*, WKView*, CGRect) | _WKViewDraw(CGContext*, WKView*, CGRect) | _WKViewDraw(CGContext*, WKView*, CGRect) | -[WebHTMLView drawSingleRect:] | -[WebFrame(WebInternal) _drawRect:contentsOnly:] | WebCore::FrameView::paintContents(WebCore::GraphicsContext*, WebCore::IntRect const&) | WebCore::RenderLayer::paint(WebCore::GraphicsContext*, WebCore::IntRect const&, WebCore::PaintRestriction, WebCore::RenderObject*) | WebCore::RenderLayer::paintLayer(WebCore::RenderLayer*, WebCore::GraphicsContext*, WebCore::IntRect const&, bool, WebCore::PaintRestriction, WebCore::RenderObject*, bool, bool) | WebCore::RenderLayer::paintLayer(WebCore::RenderLayer*, WebCore::GraphicsContext*, WebCore::IntRect const&, bool, WebCore::PaintRestriction, WebCore::RenderObject*, bool, bool) | WebCore::RenderBlock::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintObject(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintChildren(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintObject(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintChildren(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintObject(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintChildren(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintObject(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderFlow::paintLines(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RootInlineBox::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::InlineFlowBox::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::InlineTextBox::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::paintTextWithShadows(WebCore::GraphicsContext*, WebCore::Font const&, WebCore::TextRun const&, int, int, WebCore::IntPoint const&, int, int, int, int, WebCore::ShadowData*, bool) | WebCore::GraphicsContext::drawText(WebCore::Font const&, WebCore::TextRun const&, WebCore::IntPoint const&, int, int) | WebCore::Font::drawSimpleText(WebCore::GraphicsContext*, WebCore::TextRun const&, WebCore::FloatPoint const&, int, int) const | WebCore::Font::drawGlyphBuffer(WebCore::GraphicsContext*, WebCore::GlyphBuffer const&, WebCore::TextRun const&, WebCore::FloatPoint&) const | WebCore::Font::drawGlyphs(WebCore::GraphicsContext*, WebCore::SimpleFontData const*, WebCore::GlyphBuffer const&, int, int, WebCore::FloatPoint const&, bool) const | CGGStateSetFont | maybeCopyTextState | calloc | malloc_zone_calloc ---- FREE 0x800c880-0x800c8a7 [size=40]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __CFRunLoopDoObservers | CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) | CA::Transaction::commit() | CA::Context::commit_transaction(CA::Transaction*) | CALayerDisplayIfNeeded | -[TileLayer display] | -[CALayer _display] | CABackingStoreUpdate | backing_callback(CGContext*, void*) | WebCore::TiledSurface::drawLayer(CALayer*, CGContext*) | WKWindowDrawRect | WKViewDisplayRect | _WKViewDraw(CGContext*, WKView*, CGRect) | _WKViewDraw(CGContext*, WKView*, CGRect) | _WKViewDraw(CGContext*, WKView*, CGRect) | _WKViewDraw(CGContext*, WKView*, CGRect) | _WKViewDraw(CGContext*, WKView*, CGRect) | -[WebHTMLView drawSingleRect:] | -[WebFrame(WebInternal) _drawRect:contentsOnly:] | WebCore::FrameView::paintContents(WebCore::GraphicsContext*, WebCore::IntRect const&) | WebCore::RenderLayer::paint(WebCore::GraphicsContext*, WebCore::IntRect const&, WebCore::PaintRestriction, WebCore::RenderObject*) | WebCore::RenderLayer::paintLayer(WebCore::RenderLayer*, WebCore::GraphicsContext*, WebCore::IntRect const&, bool, WebCore::PaintRestriction, WebCore::RenderObject*, bool, bool) | WebCore::RenderLayer::paintLayer(WebCore::RenderLayer*, WebCore::GraphicsContext*, WebCore::IntRect const&, bool, WebCore::PaintRestriction, WebCore::RenderObject*, bool, bool) | WebCore::RenderBlock::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintObject(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintChildren(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintObject(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintChildren(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintObject(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintChildren(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderBlock::paintObject(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RenderFlow::paintLines(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::RootInlineBox::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::InlineFlowBox::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::InlineTextBox::paint(WebCore::RenderObject::PaintInfo&, int, int) | WebCore::paintTextWithShadows(WebCore::GraphicsContext*, WebCore::Font const&, WebCore::TextRun const&, int, int, WebCore::IntPoint const&, int, int, int, int, WebCore::ShadowData*, bool) | WebCore::GraphicsContext::restorePlatformState() | CGContextRestoreGState | CGGStackRestore | CGGStateRelease | textStateRelease | free ALLOC 0x800c880-0x800c8bf [size=64]: thread_a0a8c4e0 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | CA::timer_callback(__CFRunLoopTimer*, void*) | run_animation_callbacks(double, void*) | -[UIViewAnimationState animationDidStop:finished:] | -[UIViewAnimationState sendDelegateAnimationDidStop:finished:] | -[UINavigationTransitionView _navigationTransitionDidStop] | -[UIView(Hierarchy) removeFromSuperview] | -[UITextField resignFirstResponder] | -[UIFieldEditor resignFirstResponder] | -[UIKeyboardImpl setDelegate:] | -[UIKeyboardImpl setDelegate:force:] | -[UITextInteractionAssistant setGestureRecognizers] | -[UITextInteractionAssistant addTwoFingerRangedSelectRecognizer] | -[UILongPressGestureRecognizer initWithTarget:action:] | -[__NSPlaceholderSet init] | -[__NSPlaceholderSet initWithCapacity:] | __CFSetInit | _CFRuntimeCreateInstance | malloc_zone_mallocRead the article
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Aggregating cache data from OCEP in CQL
- by Manju James
There are several use cases where OCEP applications need to join stream data with external data, such as data available in a Coherence cache. OCEP’s streaming language, CQL, supports simple cache-key based joins of stream data with data in Coherence (more complex queries will be supported in a future release). However, there are instances where you may need to aggregate the data in Coherence based on input data from a stream. This blog describes a sample that does just that. For our sample, we will use a simplified credit card fraud detection use case. The input to this sample application is a stream of credit card transaction data. The input stream contains information like the credit card ID, transaction time and transaction amount. The purpose of this application is to detect suspicious transactions and send out a warning event. For the sake of simplicity, we will assume that all transactions with amounts greater than $1000 are suspicious. The transaction history is available in a Coherence distributed cache. For every suspicious transaction detected, a warning event must be sent with maximum amount, total amount and total number of transactions over the past 30 days, as shown in the diagram below. Application Input Stream input to the EPN contains events of type CCTransactionEvent. This input has to be joined with the cache with all credit card transactions. The cache is configured in the EPN as shown below: <wlevs:caching-system id="CohCacheSystem" provider="coherence"/> <wlevs:cache id="CCTransactionsCache" value-type="CCTransactionEvent" key-properties="cardID, transactionTime" caching-system="CohCacheSystem"> </wlevs:cache> Application Output The output that must be produced by the application is a fraud warning event. This event is configured in the spring file as shown below. Source for cardHistory property can be seen here. <wlevs:event-type type-name="FraudWarningEvent"> <wlevs:properties type="tuple"> <wlevs:property name="cardID" type="CHAR"/> <wlevs:property name="transactionTime" type="BIGINT"/> <wlevs:property name="transactionAmount" type="DOUBLE"/> <wlevs:property name="cardHistory" type="OBJECT"/> </wlevs:properties </wlevs:event-type> Cache Data Aggregation using Java Cartridge In the output warning event, cardHistory property contains data from the cache aggregated over the past 30 days. To get this information, we use a java cartridge method. This method uses Coherence’s query API on credit card transactions cache to get the required information. Therefore, the java cartridge method requires a reference to the cache. This may be set up by configuring it in the spring context file as shown below: <bean class="com.oracle.cep.ccfraud.CCTransactionsAggregator"> <property name="cache" ref="CCTransactionsCache"/> </bean> This is used by the java class to set a static property: public void setCache(Map cache) { s_cache = (NamedCache) cache; } The code snippet below shows how the total of all the transaction amounts in the past 30 days is computed. Rest of the information required by CardHistory object is calculated in a similar manner. Complete source of this class can be found here. To find out more information about using Coherence's API to query a cache, please refer Coherence Developer’s Guide. public static CreditHistoryData(String cardID) { … Filter filter = QueryHelper.createFilter("cardID = :cardID and transactionTime :transactionTime", map); CardHistoryData history = new CardHistoryData(); Double sum = (Double) s_cache.aggregate(filter, new DoubleSum("getTransactionAmount")); history.setTotalAmount(sum); … return history; } The java cartridge method is used from CQL as seen below: select cardID, transactionTime, transactionAmount, CCTransactionsAggregator.execute(cardID) as cardHistory from inputChannel where transactionAmount1000 This produces a warning event, with history data, for every credit card transaction over $1000. That is all there is to it. The complete source for the sample application, along with the configuration files, is available here. In the sample, I use a simple java bean to load the cache with initial transaction history data. An input adapter is used to create and send transaction events for the input stream.Read the article
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How to verify the Liskov substitution principle in an inheritance hierarchy?
- by Songo
Inspired by this answer: Liskov Substitution Principle requires that Preconditions cannot be strengthened in a subtype. Postconditions cannot be weakened in a subtype. Invariants of the supertype must be preserved in a subtype. History constraint (the "history rule"). Objects are regarded as being modifiable only through their methods (encapsulation). Since subtypes may introduce methods that are not present in the supertype, the introduction of these methods may allow state changes in the subtype that are not permissible in the supertype. The history constraint prohibits this. I was hoping if someone would post a class hierarchy that violates these 4 points and how to solve them accordingly. I'm looking for an elaborate explanation for educational purposes on how to identify each of the 4 points in the hierarchy and the best way to fix it. Note: I was hoping to post a code sample for people to work on, but the question itself is about how to identify the faulty hierarchies :)Read the article
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Basic C question, concerning memory allocation and value assignment
- by VHristov
Hi there, I have recently started working on my master thesis in C that I haven't used in quite a long time. Being used to Java, I'm now facing all kinds of problems all the time. I hope someone can help me with the following one, since I've been struggling with it for the past two days. So I have a really basic model of a database: tables, tuples, attributes and I'm trying to load some data into this structure. Following are the definitions: typedef struct attribute { int type; char * name; void * value; } attribute; typedef struct tuple { int tuple_id; int attribute_count; attribute * attributes; } tuple; typedef struct table { char * name; int row_count; tuple * tuples; } table; Data is coming from a file with inserts (generated for the Wisconsin benchmark), which I'm parsing. I have only integer or string values. A sample row would look like: insert into table values (9205, 541, 1, 1, 5, 5, 5, 5, 0, 1, 9205, 10, 11, 'HHHHHHH', 'HHHHHHH', 'HHHHHHH'); I've "managed" to load and parse the data and also to assign it. However, the assignment bit is buggy, since all values point to the same memory location, i.e. all rows look identical after I've loaded the data. Here is what I do: char value[10]; // assuming no value is longer than 10 chars int i, j, k; table * data = (table*) malloc(sizeof(data)); data->name = "table"; data->row_count = number_of_lines; data->tuples = (tuple*) malloc(number_of_lines*sizeof(tuple)); tuple* current_tuple; for(i=0; i<number_of_lines; i++) { current_tuple = &data->tuples[i]; current_tuple->tuple_id = i; current_tuple->attribute_count = 16; // static in our system current_tuple->attributes = (attribute*) malloc(16*sizeof(attribute)); for(k = 0; k < 16; k++) { current_tuple->attributes[k].name = attribute_names[k]; // for int values: current_tuple->attributes[k].type = DB_ATT_TYPE_INT; // write data into value-field int v = atoi(value); current_tuple->attributes[k].value = &v; // for string values: current_tuple->attributes[k].type = DB_ATT_TYPE_STRING; current_tuple->attributes[k].value = value; } // ... } While I am perfectly aware, why this is not working, I can't figure out how to get it working. I've tried following things, none of which worked: memcpy(current_tuple->attributes[k].value, &v, sizeof(int)); This results in a bad access error. Same for the following code (since I'm not quite sure which one would be the correct usage): memcpy(current_tuple->attributes[k].value, &v, 1); Not even sure if memcpy is what I need here... Also I've tried allocating memory, by doing something like: current_tuple->attributes[k].value = (int *) malloc(sizeof(int)); only to get "malloc: * error for object 0x100108e98: incorrect checksum for freed object - object was probably modified after being freed." As far as I understand this error, memory has already been allocated for this object, but I don't see where this happened. Doesn't the malloc(sizeof(attribute)) only allocate the memory needed to store an integer and two pointers (i.e. not the memory those pointers point to)? Any help would be greatly appreciated! Regards, VassilRead the article
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Landscape orientation for UITabBarController?
- by gingersnap
The UITabBarController does not allow landscape orientation. So I used a subclass of UITabBarContoller (called RotatingTabBarController). Its sole purpose it to allow rotation by returning YES to shouldAutorotateToInterfaceOrientation call. The problem is that when you rotate the iPhone in simulator it gives the following malloc error. malloc: *** error for object 0x3888000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug I am using 3.0 SDK with Xcode 3.2 on Snow Leopard. I set a breakpoint in malloc_error_break but I can not trace it back to my code. Is there something I can do to make this error go away? Here is the RotatingTabBarController class: #import <UIKit/UIKit.h> @interface RotatingTabBarController : UITabBarController { } @end @implementation RotatingTabBarController -(BOOL)shouldAutorotateToInterfaceOrientation:UIInterfaceOrientation)interfaceOrientation { return YES; } @end Update: I tried the same with a category. But it gives the same malloc error. // UITabBarController+Rotation.h @interface UITabBarController (rotation) - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation; @end // UITabBarController+Rotation.m #import "UITabBarController+Rotation.h" @implementation UITabBarController (rotation) - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return YES; } @end Backtrace [Session started at 2009-09-05 12:13:19 -0400.] Untitled(992,0xa06d9500) malloc: *** error for object 0x2024000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug Untitled(992,0xa06d9500) malloc: *** error for object 0x2014000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug [Session started at 2009-09-05 12:13:27 -0400.] GNU gdb 6.3.50-20050815 (Apple version gdb-1344) (Fri Jul 3 01:19:56 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "x86_64-apple-darwin".Attaching to process 992. sharedlibrary apply-load-rules all (gdb) bt #0 0x951908fa in mach_msg_trap () #1 0x95191067 in mach_msg () #2 0x30244d62 in CFRunLoopRunSpecific () #3 0x30244628 in CFRunLoopRunInMode () #4 0x32044c31 in GSEventRunModal () #5 0x32044cf6 in GSEventRun () #6 0x309021ee in UIApplicationMain () #7 0x00002608 in main (argc=1, argv=0xbfffef94) at /Users/vishwas/Desktop/Untitled/main.m:13 (gdb)Read the article
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who free's setvbuf buffer?
- by Evan Teran
So I've been digging into how the stdio portion of libc is implemented and I've come across another question. Looking at man setvbuf I see the following: When the first I/O operation occurs on a file, malloc(3) is called, and a buffer is obtained. This makes sense, your program should have a malloc in it for I/O unless you actually use it. My gut reaction to this is that libc will clean up its own mess here. Which I can only assume it does because valgrind reports no memory leaks (they could of course do something dirty and not allocate it via malloc directly... but we'll assume that it literally uses malloc for now). But, you can specify your own buffer too... int main() { char *p = malloc(100); setvbuf(stdio, p, _IOFBF, 100); puts("hello world"); } Oh no, memory leak! valgrind confirms it. So it seems that whenever stdio allocates a buffer on its own, it will get deleted automatically (at the latest on program exit, but perhaps on stream close). But if you specify the buffer explicitly, then you must clean it up yourself. There is a catch though. The man page also says this: You must make sure that the space that buf points to still exists by the time stream is closed, which also happens at program termination. For example, the following is invalid: Now this is getting interesting for the standard streams. How would one properly clean up a manually allocated buffer for them, since they are closed in program termination? I could imagine a "clean this up when I close flag" inside the file struct, but it get hairy because if I read this right doing something like this: setvbuf(stdio, 0, _IOFBF, 100); printf("hello "); setvbuf(stdio, 0, _IOLBF, 100); printf("world\n"); would cause 2 allocations by the standard library because of this sentence: If the argument buf is NULL, only the mode is affected; a new buffer will be allocated on the next read or write operation.Read the article