Search Results

Search found 1781 results on 72 pages for 'magic c0d3r'.

Page 60/72 | < Previous Page | 56 57 58 59 60 61 62 63 64 65 66 67  | Next Page >

• Anyone else experiencing high rates of Linux server crashes during a leap second day?

  - by Bron Gondwana

  POSTMORTEM Anticlimax: only thing that died was my VPN (openvpn) link to the cluster, so there was an exciting few seconds while it re-established. Everything else was fine. Starting back ntp everywhere. If you look at Marco's blog at http://my.opera.com/marcomarongiu/blog/2012/06/01/an-humble-attempt-to-work-around-the-leap-second - he has a solution for phasing the time change over 24 hours using ntpd -x to avoid the 1 second skip. Give that a go if it matters to you. For the systems I run, the jump isn't a problem. Just today, Sat June 30th - starting soon after the start of the day GMT. We've had a handful of blades in different datacentres as managed by different teams all go dark - not responding to pings, screen blank. They're all running Debian Squeeze - with everything from stock kernel to custom 3.2.21 builds. Most are Dell M610 blades, but I've also just lost a Dell R510 and other departments have lost machines from other vendors too. There was also an older IBM x3550 which crashed and which I thought might be unrelated, but now I'm wondering. The one crash which I did get a screen dump from said: [3161000.864001] BUG: spinlock lockup on CPU#1, ntpd/3358 [3161000.864001] lock: ffff88083fc0d740, .magic: dead4ead, .owner: imapd/24737, .owner_cpu: 0 Unfortunately the blades all supposedly had kdump configured, but they died so hard that kdump didn't trigger - and they had console blanking turned on. I've disabled console blanking now, so fingers crossed I'll have more information after the next crash. Just want to know if it's a common thread or "just us". It's really odd that they're different units in different datacentres bought at different times and run by different admins (I run the FastMail.FM ones)... and now even different vendor hardware. Most of the machines which crashed had been up for weeks/months and were running 3.1 or 3.2 series kernels. The most recent crash was a machine which had only been up about 6 hours running 3.2.21. THE WORKAROUND Ok people, here's how I worked around it. disabled ntp: /etc/init.d/ntp stop created http://linux.brong.fastmail.fm/2012-06-30/fixtime.pl (code stolen from Marco, see blog posts in comments) ran fixtime.pl without an argument to see that there was a leap second set ran fixtime.pl with an argument to remove the leap second NOTE: depends on adjtimex. I've put a copy of the squeeze adjtimex binary at http://linux.brong.fastmail.fm/2012-06-30/adjtimex - it will run without dependencies on a squeeze 64 bit system. If you put it in the same directory as fixtime.pl, it will be used if the system one isn't present. Obviously if you don't have squeeze 64 bit... find your own. I'm going to start ntp again tomorrow. As an anonymous user suggested - an alternative to running adjtimex is to just set the time yourself, which will presumably also clear the leapsecond counter.

  Read the article

• Apache Alias subfolder and starting with dot

  - by MauricioOtta

  I have a multi purpose server running ArchLinux that currently serves multiple virtual hosts from /var/www/domains/EXAMPLE.COM/html /var/www/domains/EXAMPLE2.COM/html I deploy those websites (mostly using Kohana framework) using a Jenkins job by checking out the project, removes the .git folder and ssh-copy the tar.gz to /var/www/domains/ on the server and untars it. Since I don't want to have to re-install phpMyAdmin after each deploy, I decided to use an alias. I would like the alias to be something like /.tools/phpMyAdmin/ so I could have more "tools" later if I wanted to. I have tried just changing the default httpd-phpmyadmin.conf that was installed by following the official WIKI: https://wiki.archlinux.org/index.php/Phpmyadmin Alias /.tools/phpMyAdmin/ "/usr/share/webapps/phpMyAdmin" <Directory "/usr/share/webapps/phpMyAdmin"> AllowOverride All Options FollowSymlinks Order allow,deny Allow from all php_admin_value open_basedir "/var/www/:/tmp/:/usr/share/webapps/:/etc/webapps:/usr/share/pear/" </Directory> Changing only that, doesn't seem to work with my current setup on the server, and apache forwards the request to the framework which 404s (as there's no route to handle /.tools/phpAdmin). I have Mass Virtual hosting enable and setup like this: # # Use name-based virtual hosting. # NameVirtualHost *:8000 # get the server name from the Host: header UseCanonicalName On # splittable logs LogFormat "%{Host}i %h %l %u %t \"%r\" %s %b" vcommon CustomLog logs/access_log vcommon <Directory /var/www/domains> # ExecCGI is needed here because we can't force # CGI execution in the way that ScriptAlias does Options FollowSymLinks ExecCGI AllowOverride All Order allow,deny Allow from all </Directory> RewriteEngine On # a ServerName derived from a Host: header may be any case at all RewriteMap lowercase int:tolower ## deal with normal documents first: # allow Alias /icons/ to work - repeat for other aliases RewriteCond %{REQUEST_URI} !^/icons/ # allow CGIs to work RewriteCond %{REQUEST_URI} !^/cgi-bin/ # do the magic RewriteCond %{SERVER_NAME} ^(www\.|)(.*) RewriteRule ^/(.*)$ /var/www/domains/${lowercase:%2}/html/$1 ## and now deal with CGIs - we have to force a MIME type RewriteCond %{REQUEST_URI} ^/cgi-bin/ RewriteRule ^/(.*)$ /var/www/domains/${lowercase:%{SERVER_NAME}}/cgi-bin/$1 [T=application/x-httpd-cgi] There is also nginx running on this server on port 80 as a reverse proxy for Apache: location ~ \.php$ { proxy_pass http://127.0.0.1:8000; } Everything else was setup by following the official WIKI so I don't think those would cause trouble. Do I need to have the alias for phpMyAdmin setup along the mass virtual hosting or can it be in a separate include file for that alias to work?

  Read the article

• How to enjoy DVD on Apple iPad

  - by user44251

  I believe many people spent a sleepless night yesterday waiting for the new Apple Tablet to come, just a few days ago or perhaps longer I noticed fierce debate about it, its name, size, capacity, processor, main features, price etc. And now, they can take a long breath with the new Apple Tablet named iPad officially released on 28, January, 2010 (Beijing Time). But I know a new battle just begins. iPad, sounds somewhat like iPod and it really shares some similarities in terms of shape like smart, light and portable. It has a 9.7-inch, LED-backlit, IPS display with a remarkable precise Multi-Touch screen. And yet, at just 1.5 lbs and 0.5 inches thin, it's easy to carry and use everywhere. It can greatly facilitates your experience with the web, emails, photos and videos. Right now, it can run almost 140.000 of the apps on the Apple store. It can even run the apps you have downloaded for your iPhone or iPod touch. But so far, I haven't seen any possibility that it can work with DVD, probability there is no built-in DVD-ROM or DVD player which can play DVD directly. As Apple iPad states, the video formats supported are MPEG-4 (MP4, M4V), H.264, MOV etc and audio formats accepted are AAC, Proteceted AAC, MP3, AIFF and WAV etc, those are formats that are commonly used with iMac. This could really a hard nut to crack if you want to watch your favourite DVD on this magic Apple iPad. But don't worry, there is still way out, you just need a few steps for ripping and importing DVD movies to Apple iPad with a simple application DVD to iPad converter What's on DVD to iPad Converter for Mac DVD to iPad converter for Mac is a powerful and professional application designed for the newly released Apple iPad which can rip, convert your DVD contents to Apple iPad compatible MPEG-4 (MP4, M4V), H.264, MOV etc, and other popular file formats like AVI, WMV, MPG, MKV, VOB, 3GP, FLV etc can also be converted so that you can put on your portable devices like iPod, iPhone, iRiver, BlackBerry etc. Besides, it can also extract audio from DVD videos and save as MP3, AIFF, AAC, WAV etc. Mac DVD to iPad converter has also been enhanced that can run both on PowerPC and Intel (Snow Leopard included). It can offer versatile editing features which allows you to make your own DVD videos. For example, you can cut your DVD to whatever length you like by Trim, crop off unwanted parts from DVD clips by Crop, add special effect like Gray, Emboss and Old film to make your videos more artistic. Besides, its built-in merging feature and batch mode allows you to join several DVD clips into a single one and do batch conversion. And more features can be expected if you afford a few minutes to try.

  Read the article

• System Reserved partition no longer marked as System

  - by Mark

  I recently posted a question to Super User about accidentally marking my external HDD's partition as Active and how I could undo my accidental mistake. I followed the instructions provided and they worked fine. This involved some command line magic and from what I understand, I did not have to really do this, but I just wanted to get things back to how they were originally. After making the fix things went back to normal in disk management. After I restarted my computer though i had an issue: BOOTMGR is missing Press Ctrl+Alt+Del to restart Rugh roh! I brought my laptop to work so I could search for a solution on my work computer and I found a nice guide on fixing the issue. To summarize the instructions, I had to reboot with my Windows 7 install disc and click the Repair button. Once there I could then repair the start-up options. One of the commenters on the site claimed you need to do this twice, as the first time the "repair" doesn't actually fix it. I found this to be true as well. I tried to repair it and it did some work, then rebooted. I then got the same error again. I booted from the CD again and repaired the start-up options then after this second time Windows started to boot up. Before the restart I got a nice info window telling me that it did make repairs to the boot info (this was promising). I've been using Windows 7 for a few days now with no problem, but I just recently noticed that I now can see the System Reserved partition in Computer: (click for full size) I immediately went to disk management to see what was up. I noticed that my System Reserved partition is no longer marked as System and instead I believe the repair operation made my C: drive the system partition. I'm not fully aware of what the System partition really is but I briefly read that its a Windows 7 thing that gets created on install of Win7 that writes some BitLocker encryption stuff to a isolated partition as well as some boot files. (click for full size) How can I undo this and make the System Partition marked as System instead of my OS C: partition? How can I make it so that I don't see this partition in Computer (I believe fixing #1 will fix this) What are the implications of what the current state is and the fact that I can now browse into this new partition? Thanks in advance.

  Read the article

• Ubuntu getting wrong hostname from DHCP

  - by sam

  When provisioning new Ubuntu Precise (12.04) servers, the hostname they're getting seems to be generated from the DNS search path, not a reverse lookup on the hostname. Take the following configuration BIND is configured with the hostname, and reverse name Normal zone $TTL 600 $ORIGIN srv.local.net. @ IN SOA ns0.local.net. hostmaster.local.net. ( 2014082101 10800 3600 604800 600 ) @ IN NS ns0.local.net. @ IN MX 5 mail.local.net. my-new-server IN A 10.32.2.30 And reverse @ IN SOA ns0.local.net. hostmaster.local.net. ( 2014082101 10800 3600 604800 600 ) @ IN NS ns0.local.net. $ORIGIN 32.10.in-addr.arpa. 30.2 IN PTR my-new-server.srv.local.net. Then DHCPD is configured to hand out static leases based on mac addresses like so subnet 10.32.2.0 netmask 255.255.254.0 { option subnet-mask 255.255.254.0; option routers 10.32.2.1; option domain-name-servers 10.32.2.1; option domain-name "util.of1.local.net of1.local.net srv.local.net"; site-option-space "pxelinux"; option pxelinux.magic f1:00:74:7e; if exists dhcp-parameter-request-list { option dhcp-parameter-request-list = concat(option dhcp-parameter-request-list,d0,d1,d2,d3); } group { option pxelinux.configfile "pxelinux.cfg/pxeboot"; host my-new-server { fixed-address my-new-server.srv.local.net; hardware ethernet aa:aa:aa:bb:bb:bb; } } } So the hostname should be my-new-server.srv.local.net, however when building a Ubuntu 12.04 node, the hostname ends up as my-new-server.util.of1.local.net When building Lucid (10.04) hosts, the hostname will be correct, it's only on Precise/12.04 nodes we have the problem. Doing a normal and reverse lookup on the host and IP returns the correct result Sams-MacBook-Pro:~ sam$ host my-new-server my-new-server.srv.local.net has address 10.32.2.30 Sams-MacBook-Pro:~ sam$ host my-new-server.srv.local.net my-new-server.srv.local.net has address 10.32.2.30 Sams-MacBook-Pro:~ sam$ host 10.32.2.30 30.2.32.10.in-addr.arpa domain name pointer my-new-server.srv.local.net. The contents of the hosts file is incorrect too 127.0.0.1 localhost 127.0.1.1 my-new-server.util.of1.local.net of1.local.net srv.local.net my-new-server So it looks like when it creates the hosts file, it puts the entire contents of the DNS search path into the local address so the FQDN according to the server is the short hostname as defined, then the first domain in the search path. Is there a way to get around this behaviour, or fix this so it gets the hostname correctly? It's picking up the first part of the hostname, then the rest is wrong.

  Read the article

• joining text files with 600M+ lines

  - by dnkb

  I have two files huge.txt and small.txt. Huge has around 600M rows and it's 14Gigs, each line has four space separated words (tokens) and finally another space separated column with a number. Small has 150K rows with a size of ~3M, a space separated word and a number. Both Files are sorted using the sort command, with no extra options. The words in both files may include apostrophes (') and dashes (-). The deisred output would contain all columns from the huge.txt and the second column (the number) from small txt where the first word of huge.txt and the first word of small.txt match. My attemtpts below failed miserably with the following error: cat huge.txt|join -o 1.1 1.2 1.3 1.4 2.2 - small.txt > output.txt join: memory exhausted What I suspect is that the sorting order isn't right somehow even though the files are pre-sorted using: sort -k1 huge.unsorted.txt > huge.txt sort -k1 small.unsorted.txt > small.txt Problems seem to appear around words that have apostrophes (') or dashes (-). I also tried dictinoary sorting using the -d option bumping into the same error at the end. I see two ways out of this but don't know how to implement any of them. 1) Any tips how to sort the files in a way that the join command considers them to be sorted properly? 2) I was thinking of calculating MD5 or some other hashes of the strings to get rid of the apostrophes and dashes, and do the sorting and joining with the hashes instead of the strings themselves an dat the "translate" back the hashes to strings, but leave the numbers intact at the end of the lines. Since there would be only 150K hashes it's not that bad. What would be a good way to calculate individual hashes for each of the strings? Some AWK magic? See file samples at the end. Thank you! sample of huge.txt had stirred me to 46 had stirred my corruption 57 had stirred old emotions 55 had stirred something in 69 had stirred something within 40 sample of small.txt caley 114881 calf 2757974 calfed 137861 calfee 71143 calflora 154624 calfskin 148347 calgary 9416465 calgon's 94846

  Read the article

• Complete machine freezes...at a loss

  - by user28818

  Guys, We built around 12 machines a few months ago to run Ubuntu. They each have the following specs: ASUS Z8NA-D6 motherboard Dual quad core Intel(R) Xeon(R) CPU E5520 @ 2.27GHz OCZ Mod Extreme Pro 500W power supply 12 GB Kingston RAM Nvidia GeForce 9800 GT graphics card My machine ran well for awhile. However, it started experiencing random lockups. These lockups are not X lockups, they are complete system freezes. The nic stops responding, the magic sysrq buttons won't work. The machine is dead. I first suspected RAM. Memtest86 didn't find anything, but I replaced the RAM anyway. Still, lockups. So I replaced the graphics card. Still, more lockups. They became more and more frequent and started to happen 2-3 times a day. So I replaced the motherboard and power supply in one fell swoop. Suddenly, no more lockups! Woohoo! Except, a week later, in the morning, the machine wouldn't wake up. I reset it, started it up, and the log files showed the last entry at around 11 pm the evening before. This has started occurring with more frequency...now just about every morning I come in, the machine is locked up, and has been since the night before. Yesterday, in the 3 weeks since I replaced the motherboard and power supply, the machine actually locked up on in in mid-work. This is the first time since replacing the two (MB and PS) that this happened while I was using it. All others occurred while I was away. I'm at a loss. Nothing is in syslog or message that would indicate a problem around the time of the lockup. Temps are good...I use lmsensors to monitor and have a script that writes the output to file every minute. They never get that high. The only thing I haven't replaced at this point is the case and the harddrives. I doubt either could be the cause. What would you do if you were in my shoes? Is there a troubleshooting approach I'm missing? For the record, all of the other machines, all eleven of them, don't have any problems. They're all running the same version of Ubuntu (Lucid) that I am. Thanks!

  Read the article

• Apache will not stop/start gracefully

  - by ddjammin

  CentOs 6 64bit running apache 2.2.15-29.el6.centos. When I try to stop/start or restart httpd I get an error that says it has failed. A tail of the error log is below. I also noticed that a httpd.pid file is not created even though it is configured in the main conf file. If I set selinux to permissive, it works just fine. I do not want to run it with selinux disabled. If I delete the SSL_Mutex file it will start. HTTPD was running fine until I tried to add the ssl configuration. I copied over the ssl.conf file from a working server into the conf.d folder. I also copied a sslcert folder into the conf folder. It contains the certs, key, csr and password file. I think the problem has to do with the selinux context for the sslcert folder that was copied but I am not certain and not sure how to fix it. Below is the security context for the sslcert folder after executing restorecon -R sslcert ls -Z -rw-r--r--. root root system_u:object_r:httpd_config_t:s0 httpd.conf -rw-r--r--. root root system_u:object_r:httpd_config_t:s0 magic **drwxr-xr-x. root root system_u:object_r:httpd_config_t:s0 sslcert** tail -f /var/log/httpd/error_log [Thu Oct 17 13:33:19 2013] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec) [Thu Oct 17 13:33:20 2013] [notice] Digest: generating secret for digest authentication ... [Thu Oct 17 13:33:20 2013] [notice] Digest: done [Thu Oct 17 13:33:20 2013] [warn] pid file /etc/httpd/logs/ssl.pid overwritten -- Unclean shutdown of previous Apache run? [Thu Oct 17 13:33:20 2013] [notice] Apache/2.2.15 (Unix) DAV/2 mod_ssl/2.2.15 OpenSSL/1.0.0-fips configured -- resuming normal operations [Thu Oct 17 21:04:48 2013] [notice] caught SIGTERM, shutting down [Thu Oct 17 21:06:42 2013] [notice] **SELinux policy enabled; httpd running as context system_u:system_r:httpd_t:s0** [Thu Oct 17 21:06:42 2013] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec) [Thu Oct 17 21:06:42 2013] [error] (17)File exists: Cannot create SSLMutex with file `/etc/httpd/logs/ssl_mutex' I also saw mention of possible issues with semaphores. Below is the output of the current semaphores and apache is currently not running. ipcs -s ------ Semaphore Arrays -------- key semid owner perms nsems 0x00000000 0 root 600 1 0x00000000 65537 root 600 1 Finally selinux reports the following error. `sealert -a /var/log/audit/audit.log` 0% donetype=AVC msg=audit(1382034755.118:420400): avc: denied { write } for pid=3393 comm="httpd" name="ssl_mutex" dev=dm-0 ino=9513484 scontext=unconfined_u:system_r:httpd_t:s0 tcontext=unconfined_u:object_r:httpd_log_t:s0 tclass=file **** Invalid AVC allowed in current policy *** 100% doneERROR: failed to read complete file, 1044649 bytes read out of total 1043317 bytes (/var/log/audit/audit.log) found 1 alerts in /var/log/audit/audit.log -------------------------------------------------------------------------------- SELinux is preventing /usr/sbin/httpd from remove_name access on the directory ssl_mutex.

  Read the article

• Wifi network stopped being visible (and usable) (Linksys wag320n)

  - by s427

  Basically, my wifi network simply stopped working for no apparent reason. It doesn't appear in the list of the available networks anymore. I can see all my neighbors' networks, but not mine. It's as if it doesn't exist anymore. The internet connection (non-wifi), which goes through the same modem/router, is fine though. I already had a similar problem about one year ago (see here: Wifi network SSID not visible ), just after buying this very modem. I finally got it to work after performing two factory resets and getting rid of the Cisco "Magic" software; but this time it's not working. I use a linksys router-modem (WAG320N) which is directly connected (via network cable) to my desktop computer (Windows 7). I have (mainly) two devices that use the wifi network: my phone (Samsung Galaxy Nexus) and an Asus tablet (TF201, aka Transformer Prime). I also resurrected an old laptop computer (Dell, running Windows XP) to test that, and it doesn't see anything either (apart from the 20 other wifi networks, of course ^^). This wifi network was working just fine and has been for about a year. I haven't touched the modem settings so I have no idea what's causing the problem. I tried: making my phone "forget" about my network, hoping it would see it again after that: no luck. re-entering the network informations (SSID/password) manually on my phone: still no luck (says it's not in range) exporting the modem configuration, resetting the modem (factory reset, via modem admin), restarting it, importing the configuration: nope. factory reset, turning it off for 15 minutes, restarting, re-factory reset, and entering the configuration manually: still nothing. Has anybody experienced something similar before? Have you any suggestion to fix that? Thanks in advance. PS: to clear things up, here are the settings of my modem regarding wifi: Basic wireless settings: Configuration: manual Radio Band: 2.4GHz Wireless Network Mode: B/G/N-Mixed SSID: s427 Channel Bandwidth: Wide - 40 MHz Channel Wide Channel: 9 - 2.452GHz Standard Channel: 11 - 2.462GHz SSID Broadcast: Enable Advanced Wireless Settings AP Isolation: Disable Authentication Type: Auto Basic Rate: Default Transmission Rate: Auto N Transmission Rate: Auto CTS Protection Mode: Disable Beacon Interval: 100 DTIM Interval: 1 Fragmentation Threshold: 2346 RTS Threshold: 2346

  Read the article

• Feedback on "market manipulation", a peripheral game mechanic for a satirical MMO

  - by BerndBrot

  This question asks for feedback on a specific game-mechanic. Since there is not one right feedback on a game mechanic, I tried to provide enough context and guidelines to still make it possible for users to rate answers and to accept an answer as the best answer (following these criteria from Writer.SE's meta website). Please comment if you have any suggestions on how I could improve the question in that regard. So, let's begin with the game itself and some of its elements which are relevant for this question. Context I'm working on a satirical, text-based multiplayer adventure and role-playing game set in modern-day London. The game resolves around the concept of sin and features a myriad of (venomous) allusions to all the things that go wrong in this world. Players can choose between character classes like bullshit artist (consultant), bankster, lawyer, mobster, celebrity, politician, etc. In order to complete the game, the player has to live so sinfully with regard to any of the seven deadly sins that a demon is willing to offer them a contract of sponsorship. On their quest to live a sinful live, characters explore more and more locations of modern-day London (on a GoogleMap), fight "monsters" like insurance sales agents or Jehovah's Witnesses, and complete quests, like building a PowerPoint presentation out of marketing buzz words or keeping up a number of substance abuse effects in order to progress on the gluttony path. Battles are turn based with both combatants having a deck of cards, with which they try to make their enemy give in to temptations of all sorts. Tempted enemies sometimes become contacts (an item drop mechanic), which can be exploited for various benefits, depending on their area of influence (finance, underworld, bureaucracy, etc.), level of influence, and kind of sway that the player has over them (bribed, seduced, threatened, etc.) Once a contract has been exploited, the player loses that contact. Most actions require turns. Turns are limited, but refill each day. Criteria A number of peripheral game mechanics are supposed to represent real world abuses and mischief in a humorous way integrate real world data and events to strengthen the feeling of relevance of the game's humor with regard to real world problems add fun ways of interacting with other players add ways for players to express themselves through game-play Market manipulation is one such peripheral game mechanic and should fulfill all of these goals. Market manipulation This is my initial design of the mechanic: Players can enter the London Stock Exchange (LSE) (without paying a turn) LSE displays the stock prices of a number of companies in industries like weapons or tobacco as well as some derivatives based on wheat and corn. The stock prices are calculated based on the actual stock prices of these companies and derivatives (in real time) any market manipulations that were conducted by the players any market corrections of the system Players can buy and sell shares with cash, a resource in the game, at current in-game market value (without paying a turn). Players can manipulate the market, i.e. let the price of a share either rise or fall, by some amount, over a certain period of time. Manipulating the market requires 1 turn A contact in the financial sector (see above). The higher the level of influence of the contact, the stronger the effect of the manipulation on the stock price, and/or the shorter it takes for the manipulation to manifest itself. Market manipulation also adds a crime to the player's record. (There are a multitude of ways to take care of that, but it is still another "cost" of market manipulations.) The system continuously corrects market manipulations by letting the in-game prices converge towards their real world counterparts at a rate of 2% of the difference between the two per hour. Because of this market correction mechanism, pushing up prices (and screwing down prices) becomes increasingly difficult the higher (lower) the price already is. Whenever food prices reach a certain level, in-game stories are posted about hunger catastrophes happening somewhere far, far away (maybe with links to real world news stories). Whenever a player sells a certain number of shares with a sufficiently high margin, they are mentioned in that day's in-game financial news. Since the number of stock options is very limited, players will inevitably collide in their efforts to manipulate the market in their favor. Hopefully, it will also be a fun side-arena for guilds and covenants to fight each other. Question(s) What do you think of this mechanism given the criteria for peripheral game mechanics that I specified for my game? Do you have any ideas how the mechanic could be improved with regard to these criteria (or otherwise)? Could it be improved to allow for more expressive game-play, or involve an allusion to some other real world madness (like short selling, leveraging, or some other banking magic)? Are there any game-theoretic problems with this mechanic, like maybe certain dominant individual strategies that, collectively, lead to every player profiting and thus eliminating the idea of market manipulation PVP? Also, if you like (or dislike) this question, feel free to participate in the discussion on GDSE meta: "Should we be more lax with regard to SE's question/answer format to make game design questions possible?"

  Read the article

• Top 10 Tips & Tricks for Oracle SQL Developer

  - by thatjeffsmith

  Being a short week due to the holiday, and with everyone enjoying their Summer vacations (apologies Southern Hemispherians), I reckoned it was a great time to do one of those lazy recap-Top 10-Reader’s Digest type posts. I’ve been sharing 1-3 tips or ‘tricks’ a week since I started blogging about SQL Developer, and I have more than enough content to write a book. But since I’m lazy, I’m just going to compile a list of my favorite ‘must know’ tips instead. I always have to leave out a few tips when I do my presentations, so now I can refer back to this list to make sure I’m not forgetting anything. So without further ado… 1. Configure Your Preferences Yes, there are a LOT of options. But you don’t need to worry about all of them just yet. I do recommend you take a quick look at these ones in particular. Whether you’re new to the tool or have been using it for 5 years, don’t overlook these settings! 2. Disable Extensions You Aren’t Using If you’re not using Data Miner, or if you’re not working on a Migration – disable those extensions! SQL Developer will run leaner & meaner, plus the user interface will be a bit more simplified making the tool easier to navigate as well. 3. SQL Recall via Keyboard Access your history via the keyboard! Cycle through your recent SQL statements just using these magic key strokes! Ctrl+Up or Ctrl+Down. 4. Format Your Query Output Directly to CSV, XML, HTML, etc Have the query results pre-formatted in the format of your choice! Too lazy to run the Export wizard for your query result sets? Just add the SQL Developer output hints to your statement and have the output auto-magically formatted to the style of your choice! 5. Drag & Drop Multiple Tables to the Worksheet SQL Developer will auto-join the related objects. You can then toggle over to the Query Builder to toggle off the columns you don’t want to query. I guarantee this tip will save you time if you’re joining 3 or more tables! 6. Drag & Drop Multiple Tables to a Relational Model A pretty picture is worth a few dozen DDL scripts? SQL Developer does data modeling! If you ctrl-drag a table to a model, it will take that table and any related tables and reverse engineer them to a relational model! You can then print it out or export it to HTML, PDF, etc. 7. View Your PL/SQL Execution Output Automatically Function returns a refcursor? Procedure had 3 out parameters? When you run these programs via the Procedure Editor, we automatically capture the output and place them into one or more data grids for you to browse. 8. Disable Automatic Code Insight and Use It On-Demand Code Editor – Completion Insight – Enable Completion Auto-Popup (Keyword being Auto) Some folks really don’t like it when their IDEs or word-processors try to do ‘too much’ for them. Thankfully SQL Developer allows you to either increase the delay before it attempts to auto-complete your text OR to disable the automatic bit. Instead, you can invoke it on-demand. 9. Interactive Debugging – Change Your Variable Values as You Step Through Your PLSQL Watches aren’t just for watching. You can actually interact with your programs and ‘see what happens’ when X = 256 instead of 1. 10. Ditch the Tree View for the Schema Browser There’s nothing wrong with the Connection tree for browsing your database objects. But some folks just can’t seem to get comfortable with it. So, we built them a Schema Browser that uses a drop down control instead for changing up your schema and object types. Already Know This Stuff, Want More? Just check out my SQL Developer resource page, it’s one of the main links on the top of this page. Or if you can’t find something, just drop me a note in the form of a comment on this page and I’ll do my best to find it or write it for you.

  Read the article

• What’s New for Oracle Commerce? Executive QA with John Andrews, VP Product Management, Oracle Commerce

  - by Katrina Gosek

  Oracle Commerce was for the fifth time positioned as a leader by Gartner in the Magic Quadrant for E-Commerce. This inspired me to sit down with Oracle Commerce VP of Product Management, John Andrews to get his perspective on what continues to make Oracle a leader in the industry and what’s new for Oracle Commerce in 2013. Q: Why do you believe Oracle Commerce continues to be a leader in the industry? John: Oracle has a great acquisition strategy – it brings best-of-breed technologies into the product fold and then continues to grow and innovate them. This is particularly true with products unified into the Oracle Commerce brand. Oracle acquired ATG in late 2010 – and then Endeca in late 2011. This means that under the hood of Oracle Commerce you have market-leading technologies for cross-channel commerce and customer experience, both designed and developed in direct response to the unique challenges online businesses face. And we continue to innovate on capabilities core to what our customers need to be successful – contextual and personalized experience delivery, merchant-inspired tools, and architecture for performance and scalability. Q: It’s not a slow moving industry. What are you doing to keep the pace of innovation at Oracle Commerce? John: Oracle owes our customers the most innovative commerce capabilities. By unifying the core components of ATG and Endeca we are delivering on this promise. Oracle Commerce is continuing to innovate and redefine how commerce is done and in a way that drive business results and keeps customers coming back for experiences tailored just for them. Our January and May 2013 releases not only marked the seventh significant releases for the solution since the acquisitions of ATG and Endeca, we also continue to demonstrate rapid and significant progress on the unification of commerce and customer experience capabilities of the two commerce technologies. Q: Can you tell us what was notable about these latest releases under the Oracle Commerce umbrella? John: Specifically, our latest product innovations give businesses selling online the ability to get to market faster with more personalized commerce experiences in the following ways: Mobile: the latest Commerce Reference Application in this release offers a wider range of examples for online businesses to leverage for iOS development and specifically new iPad reference capabilities. This release marks the first release of the iOS Universal application that serves both the iPhone and iPad devices from a single download or binary. Business users can now drive page content management and layout of search results and category pages, as well as create additional storefront elements such as categories, facets / dimensions, and breadcrumbs through Experience Manager tools. Cross-Channel Commerce: key commerce platform capabilities have been added to support cross-channel commerce, including an expanded inventory model to maintain inventory for stores, pickup in stores and Web-based returns. Online businesses with in-store operations can now offer advanced shipping options on the web and make returns and exchange logic easily available on the web. Multi-Site Capabilities: significant enhancements to the Commerce Platform multi-site architecture that allows business users to quickly launch and manage multiple sites on the same cluster and share data, carts, and other components. First introduced in 2010, with this latest release business users can now partition or share customer profiles, control users’ site-based access, and manage personalization assets using site groups. Internationalization: continued language support and enhancements for business user tools as well and search and navigation. Guided Search now supports 35 total languages with 11 new languages (including Danish, Arabic, Norwegian, Serbian Cyrillic) added in this release. Commerce Platform tools now include localized support for 17 locales with 4 new languages (Danish, Portuguese (European), Finnish, and Thai). No development or customization is required in order for business users to use the applications in any of these supported languages. Business Tool Experience: valuable new Commerce Merchandising features include a new workflow for making emergency changes quickly and increased visibility into promotions rules and qualifications in preview mode. Oracle Commerce business tools continue to become more and more feature rich to provide intuitive, easy- to-use (yet powerful) capabilities to allow business users to manage content and the shopping experience. Commerce & Experience Unification: demonstrable unification of commerce and customer experience capabilities include – productized cartridges that provide supported integration between the Commerce Platform and Experience Management tools, cross-channel returns, Oracle Service Cloud integration, and integrated iPad application. The mission guiding our product development is to deliver differentiated, personalized user experiences across any device in a contextual manner – and to give the business the best tools to tune and optimize those user experiences to meet their business objectives. We also need to do this in a way that makes it operationally efficient for the business, keeping the overall total cost of ownership low – yet also allows the business to expand, whether it be to new business models, geographies or brands. To learn more about the latest Oracle Commerce releases and mission, visit the links below: • Hear more from John about the Oracle Commerce mission • Hear from Oracle Commerce customers • Documentation on the new releases • Listen to the Oracle ATG Commerce 10.2 Webcast • Listen to the Oracle Endeca Commerce 3.1.2 Webcast

  Read the article

• How to Get All the Windows 8 Editions on One Install Disk

  - by Taylor Gibb

  There are a lot of different versions of Windows, but you probably didn’t know that short of the Enterprise edition, the disc or image that you own contains all versions for that architecture. Read on to see how we can use them to make a universal Windows 8 install disc. Things You Will Need A x86 Version of Windows 8 A x64 Version of Windows 8 A x86 Version of Windows 8 Enterprise A x64 Version of Windows 8 Enterprise A Windows 8 PC Note: While we will use all the images above you don’t really need the Enterprise Edition. You could always leave out parts of the tutorial if you know what you are doing, if you are not comfortable with that and still want to follow through you could always grab the Enterprise evaluation images that are available for free to the public, on MSDN. Getting Started To get started you will need to Download the Windows 8 ADK from Microsoft. Once downloaded go ahead and install it, you will only need the Deployment tools so be sure to uncheck the rest of the options. Lastly you will also need to create the following folder structure on the root of your C:\ drive to make things a bit easier. C:\Windows8Root C:\Windows8Root\x86 C:\Windows8Root\x64 C:\Windows8Root\Enterprisex86 C:\Windows8Root\Enterprisex64 C:\Windows8Root\Temp C:\Windows8Root\Final OK lets get started. Making The Image The first thing we need to do is create a base image, so mount the x86 version of Windows 8 and copy its files to: C:\Windows8Root\Final Now move the install.wim file from: C:\Windows8Root\Final\sources To: C:\Windows8Root\x86 Next go ahead and copy the install.wim file from the other 3 images, Windows 8 x64, Windows 8 Enterprise x86 and Windows 8 Enterprise x64 to the respective folders in Windows8Root, the install.wim file can be located at: D:\sources\install.wim Note: The above assumes that the images are always mounted at drive D. Remember that each install.wim is different so don’t copy them to the wrong directories or the rest of the tutorial wont work. Next switch to the Metro Start Screen and open the Deployment and Imaging Tools Environment. Note: If you are not a local administrator on your PC, you will need to right-click on it and choose to run it as an administrator. Now run the following commands: Dism /Export-Image /SourceImageFile:c:\Windows8Root\x86\install.wim /SourceIndex:2 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8″ /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x86\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x86\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro with Media Center” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\Enterprisex86\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Enterprise” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x64\install.wim /SourceIndex:2 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8″ /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x64\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x64\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro with Media Center” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\Enterprisex64\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Enterprise” /compress:maximum Next navigate to: C:\Windows8Root\sources\ And create a new text file. You will need to call it: EI.cfg Then edit it to look like the following: The last thing we need to do is work some magic to get Windows Media Center added to the WMC editions of Windows 8. For that I have written a little script to make it easier for everybody, you can grab it here. Once you have downloaded it extract it. In order to use it right-click in the bottom left hand corner of the screen, and open an elevated command prompt. Then go ahead and paste the following into the command prompt window. powershell.exe -ExecutionPolicy Unrestricted -File C:\Users\Taylor\Documents\HTGWindows8Converter.ps1 Note: You will need to replace the path to the script, another thing to note is that if the path you replace it with has spaces you will need to enclose the path in quotes. The script should kick off straight away and has some progress bars you can watch while it does its thing. Half way through another Window will pop open, which will start creating your final ISO image. When its complete, close the command prompt and you should have an ISO image on the root of your C drive called: HTGWindows8.iso That’s all there is to it. 7 Ways To Free Up Hard Disk Space On Windows HTG Explains: How System Restore Works in Windows HTG Explains: How Antivirus Software Works

  Read the article

• Agile Testing Days 2012 – Day 1 – The birth of the #unicorn…

  - by Chris George

  Still riding the high from the tutorial day, I arrived at the conference venue eager to get cracking with the days talks. The opening Keynote was “Disciplined Agile Delivery: The Foundation for Scaling Agile” presented by Scott Ambler. The general ideas behind the methodology such as not re-inventing the wheel, and being goal driven, not prescriptive in how you work certainly struck chords with how we are trying to work in my team. Scott made some interesting observations about how scrum is quite prescriptive and is this really agile? I agreed with quite a few of his points on how what works for one team may not work for another. How a team works should be driven by context and reflection, not process and prescription. However was somewhat dubious about some of the statistics he rolled out towards the end. However, out of this keynote was born something that was to transcend this one presentation. During the talk, Scott mentioned on more than one occasion “In the real world”, and at one point made reference to people living in the land of unicorns and rainbows. The challenge was then laid down on twitter for all speakers to include a unicorn in their presentations… and for the most part this happened! It became an identity for this years conference, and I’m sure something that any attendee will always associate with Agile Testing Days 2012! Following this keynote, I attended “Going agile with Automated GUI Testing – Some personal insights” by Jan Zdunek from codecentric on the vendor track. My speciality is test automation, and in particular GUI testing, so this drew me to this talk more than the others. Thankfully, it was made clear from the very start that this was not peddling any particular product (even though it was on the vendor track), and Jan faithfully stuck to that. Most of the content was not new to me, but it was really comforting to hear someone else with very similar experiences to my own. In particular, things like how GUI testing is hard and is not a silver bullet; how record & replay is NOT a good thing to do (which drew a somewhat inflammatory tweet from an automation company when I tweeted that!). Something that I have started hearing around the place, and has certainly been murmuring at work is to push more of the automation coding onto the developers. After all they are the coding experts. I agree with this to a degree, but I personally enjoy coding and find it very rewarding doing so, therefore I’d be reluctant to give it up. I think there are some better alternatives such as pairing with a developer. Lastly, Jan mentioned, almost in passing, that we should consider virtualisation for gui testing for covering configuration combinations. On my project we’ve been running our win32/.NET GUI tests in cloud virtualisation for a couple of years now… I really should write about that! After lunch the second keynote of the day was by Lisa Crispin and Janet Gregory,”Myths about Agile Testing, De-Bunked”. It started off well… with the two ladies donning Medusa style head bands whilst they disbanding several myths about agile testing! I got the impression that it was perhaps not as slick as they would have liked, but then Janet was suffering with a very sore throat so kept losing her voice. Nevertheless, the presentation was captivating, and they debunked several myths such as : “Testing is dead”, “Testers must write code”, “Agile teams always deliver faster”. I didn’t take many notes for this because it was being recorded, but unfortunately the recordings have not been posted yet so I’ll write more about this when they are. The TestLab was held during a somewhat free for all time during most of the afternoon. It looked intriguing and proved to be one of the surprising experiences of the conference for me. Run by James Lyndsay and Bart Knaack, it consisted of a number of ‘stations’ that offered different testing problems. I opted for testing a mathematical drawing app call Geogebra, the task being to pair up and exploratory test it. After an allotted time, we discussed issues we’d found and decided if we wanted to continue ‘playing’ to which we all agreed! It was fun! The last track talk of the day was “Developers Exploratory Testing – Raising the bar” by Sigge Birgisson. One of the teams at Red Gate have tried Dev or Team exploratory testing a couple of times, and I was really interested to go to the presentation that prompted that. I was not disappointed! Sigge gave a first class presentation, and not only explained what DET was all about, but also how to go about implementing it. Little tips like calling it a ‘workshop’ rather than ‘testing’ I can really see working! Monday evening saw the presentation of the award for the Most Influential Agile Testing Professional Person go to a much deserved Lisa Crispin. The evening was great, with acrobatics, magic and music. My Takeaway Triple from Day 1:  Some of the cool stuff that was suggested in the GUI Testing talk, we are already doing. I should write about that! Testing is not dead! Perhaps testing will become more of a skill than a specific role, but it is certainly not dead. Team/Developer exploratory testing… seems like a no-brainer assuming you have a team who is willing.  Day 2 – Coming soon…

  Read the article

• Partition Wise Joins

  - by jean-pierre.dijcks

  Some say they are the holy grail of parallel computing and PWJ is the basis for a shared nothing system and the only join method that is available on a shared nothing system (yes this is oversimplified!). The magic in Oracle is of course that is one of many ways to join data. And yes, this is the old flexibility vs. simplicity discussion all over, so I won't go there... the point is that what you must do in a shared nothing system, you can do in Oracle with the same speed and methods. The Theory A partition wise join is a join between (for simplicity) two tables that are partitioned on the same column with the same partitioning scheme. In shared nothing this is effectively hard partitioning locating data on a specific node / storage combo. In Oracle is is logical partitioning. If you now join the two tables on that partitioned column you can break up the join in smaller joins exactly along the partitions in the data. Since they are partitioned (grouped) into the same buckets, all values required to do the join live in the equivalent bucket on either sides. No need to talk to anyone else, no need to redistribute data to anyone else... in short, the optimal join method for parallel processing of two large data sets. PWJ's in Oracle Since we do not hard partition the data across nodes in Oracle we use the Partitioning option to the database to create the buckets, then set the Degree of Parallelism (or run Auto DOP - see here) and get our PWJs. The main questions always asked are: How many partitions should I create? What should my DOP be? In a shared nothing system the answer is of course, as many partitions as there are nodes which will be your DOP. In Oracle we do want you to look at the workload and concurrency, and once you know that to understand the following rules of thumb. Within Oracle we have more ways of joining of data, so it is important to understand some of the PWJ ideas and what it means if you have an uneven distribution across processes. Assume we have a simple scenario where we partition the data on a hash key resulting in 4 hash partitions (H1 -H4). We have 2 parallel processes that have been tasked with reading these partitions (P1 - P2). The work is evenly divided assuming the partitions are the same size and we can scan this in time t1 as shown below. Now assume that we have changed the system and have a 5th partition but still have our 2 workers P1 and P2. The time it takes is actually 50% more assuming the 5th partition has the same size as the original H1 - H4 partitions. In other words to scan these 5 partitions, the time t2 it takes is not 1/5th more expensive, it is a lot more expensive and some other join plans may now start to look exciting to the optimizer. Just to post the disclaimer, it is not as simple as I state it here, but you get the idea on how much more expensive this plan may now look... Based on this little example there are a few rules of thumb to follow to get the partition wise joins. First, choose a DOP that is a factor of two (2). So always choose something like 2, 4, 8, 16, 32 and so on... Second, choose a number of partitions that is larger or equal to 2* DOP. Third, make sure the number of partitions is divisible through 2 without orphans. This is also known as an even number... Fourth, choose a stable partition count strategy, which is typically hash, which can be a sub partitioning strategy rather than the main strategy (range - hash is a popular one). Fifth, make sure you do this on the join key between the two large tables you want to join (and this should be the obvious one...). Translating this into an example: DOP = 8 (determined based on concurrency or by using Auto DOP with a cap due to concurrency) says that the number of partitions >= 16. Number of hash (sub) partitions = 32, which gives each process four partitions to work on. This number is somewhat arbitrary and depends on your data and system. In this case my main reasoning is that if you get more room on the box you can easily move the DOP for the query to 16 without repartitioning... and of course it makes for no leftovers on the table... And yes, we recommend up-to-date statistics. And before you start complaining, do read this post on a cool way to do stats in 11.

  Read the article

• Independence Day for Software Components &ndash; Loosening Coupling by Reducing Connascence

  - by Brian Schroer

  Today is Independence Day in the USA, which got me thinking about loosely-coupled “independent” software components. I was reminded of a video I bookmarked quite a while ago of Jim Weirich’s “Grand Unified Theory of Software Design” talk at MountainWest RubyConf 2009. I finally watched that video this morning. I highly recommend it. In the video, Jim talks about software connascence. The dictionary definition of connascence (con-NAY-sense) is: 1. The common birth of two or more at the same time 2. That which is born or produced with another. 3. The act of growing together. The brief Wikipedia page about Connascent Software Components says that: Two software components are connascent if a change in one would require the other to be modified in order to maintain the overall correctness of the system. Connascence is a way to characterize and reason about certain types of complexity in software systems. The term was introduced to the software world in Meilir Page-Jones’ 1996 book “What Every Programmer Should Know About Object-Oriented Design”. The middle third of that book is the author’s proposed graphical notation for describing OO designs. UML became the standard about a year later, so a revised version of the book was published in 1999 as “Fundamentals of Object-Oriented Design in UML”. Weirich says that the third part of the book, in which Page-Jones introduces the concept of connascence “is worth the price of the entire book”. (The price of the entire book, by the way, is not much – I just bought a used copy on Amazon for $1.36, so that was a pretty low-risk investment. I’m looking forward to getting the book and learning about connascence from the original source.) Meanwhile, here’s my summary of Weirich’s summary of Page-Jones writings about connascence: The stronger the form of connascence, the more difficult and costly it is to change the elements in the relationship. Some of the connascence types, ordered from weak to strong are: Connascence of Name Connascence of name is when multiple components must agree on the name of an entity. If you change the name of a method or property, then you need to change all references to that method or property. Duh. Connascence of name is unavoidable, assuming your objects are actually used. My main takeaway about connascence of name is that it emphasizes the importance of giving things good names so you don’t need to go changing them later. Connascence of Type Connascence of type is when multiple components must agree on the type of an entity. I assume this is more of a problem for languages without compilers (especially when used in apps without tests). I know it’s an issue with evil JavaScript type coercion. Connascence of Meaning Connascence of meaning is when multiple components must agree on the meaning of particular values, e.g that “1” means normal customer and “2” means preferred customer. The solution to this is to use constants or enums instead of “magic” strings or numbers, which reduces the coupling by changing the connascence form from “meaning” to “name”. Connascence of Position Connascence of positions is when multiple components must agree on the order of values. This refers to methods with multiple parameters, e.g.: eMailer.Send("[email protected]", "[email protected]", "Your order is complete", "Order completion notification"); The more parameters there are, the stronger the connascence of position is between the component and its callers. In the example above, it’s not immediately clear when reading the code which email addresses are sender and receiver, and which of the final two strings are subject vs. body. Connascence of position could be improved to connascence of type by replacing the parameter list with a struct or class. This “introduce parameter object” refactoring might be overkill for a method with 2 parameters, but would definitely be an improvement for a method with 10 parameters. This points out two “rules” of connascence:  The Rule of Degree: The acceptability of connascence is related to the degree of its occurrence. The Rule of Locality: Stronger forms of connascence are more acceptable if the elements involved are closely related. For example, positional arguments in private methods are less problematic than in public methods. Connascence of Algorithm Connascence of algorithm is when multiple components must agree on a particular algorithm. Be DRY – Don’t Repeat Yourself. If you have “cloned” code in multiple locations, refactor it into a common function.   Those are the “static” forms of connascence. There are also “dynamic” forms, including… Connascence of Execution Connascence of execution is when the order of execution of multiple components is important. Consumers of your class shouldn’t have to know that they have to call an .Initialize method before it’s safe to call a .DoSomething method. Connascence of Timing Connascence of timing is when the timing of the execution of multiple components is important. I’ll have to read up on this one when I get the book, but assume it’s largely about threading. Connascence of Identity Connascence of identity is when multiple components must reference the entity. The example Weirich gives is when you have two instances of the “Bob” Employee class and you call the .RaiseSalary method on one and then the .Pay method on the other does the payment use the updated salary?   Again, this is my summary of a summary, so please be forgiving if I misunderstood anything. Once I get/read the book, I’ll make corrections if necessary and share any other useful information I might learn.   See Also: Gregory Brown: Ruby Best Practices Issue #24: Connascence as a Software Design Metric (That link is failing at the time I write this, so I had to go to the Google cache of the page.)

  Read the article

• Talking JavaOne with Rock Star Martijn Verburg

  - by Janice J. Heiss

  JavaOne Rock Stars, conceived in 2005, are the top-rated speakers at each JavaOne Conference. They are awarded by their peers, who, through conference surveys, recognize them for their outstanding sessions and speaking ability. Over the years many of the world’s leading Java developers have been so recognized. Martijn Verburg has, in recent years, established himself as an important mover and shaker in the Java community. His “Diabolical Developer” session at the JavaOne 2011 Conference got people’s attention by identifying some of the worst practices Java developers are prone to engage in. Among other things, he is co-leader and organizer of the thriving London Java User Group (JUG) which has more than 2,500 members, co-represents the London JUG on the Executive Committee of the Java Community Process, and leads the global effort for the Java User Group “Adopt a JSR” and “Adopt OpenJDK” programs. Career highlights include overhauling technology stacks and SDLC practices at Mizuho International, mentoring Oracle on technical community management, and running off shore development teams for AIG. He is currently CTO at jClarity, a start-up focusing on automating optimization for Java/JVM related technologies, and Product Advisor at ZeroTurnaround. He co-authored, with Ben Evans, "The Well-Grounded Java Developer" published by Manning and, as a leading authority on technical team optimization, he is in high demand at major software conferences.Verburg is participating in five sessions, a busy man indeed. Here they are: CON6152 - Modern Software Development Antipatterns (with Ben Evans) UGF10434 - JCP and OpenJDK: Using the JUGs’ “Adopt” Programs in Your Group (with Csaba Toth) BOF4047 - OpenJDK Building and Testing: Case Study—Java User Group OpenJDK Bugathon (with Ben Evans and Cecilia Borg) BOF6283 - 101 Ways to Improve Java: Why Developer Participation Matters (with Bruno Souza and Heather Vancura-Chilson) HOL6500 - Finding and Solving Java Deadlocks (with Heinz Kabutz, Kirk Pepperdine, Ellen Kraffmiller and Henri Tremblay) When I asked Verburg about the biggest mistakes Java developers tend to make, he listed three: A lack of communication -- Software development is far more a social activity than a technical one; most projects fail because of communication issues and social dynamics, not because of a bad technical decision. Sadly, many developers never learn this lesson. No source control -- Developers simply storing code in local filesystems and emailing code in order to integrate Design-driven Design -- The need for some developers to cram every design pattern from the Gang of Four (GoF) book into their source code All of which raises the question: If these practices are so bad, why do developers engage in them? “I've seen a wide gamut of reasons,” said Verburg, who lists them as: * They were never taught at high school/university that their bad habits were harmful.* They weren't mentored in their first professional roles.* They've lost passion for their craft.* They're being deliberately malicious!* They think software development is a technical activity and not a social one.* They think that they'll be able to tidy it up later.A couple of key confusions and misconceptions beset Java developers, according to Verburg. “With Java and the JVM in particular I've seen a couple of trends,” he remarked. “One is that developers think that the JVM is a magic box that will clean up their memory, make their code run fast, as well as make them cups of coffee. The JVM does help in a lot of cases, but bad code can and will still lead to terrible results! The other trend is to try and force Java (the language) to do something it's not very good at, such as rapid web development. So you get a proliferation of overly complex frameworks, libraries and techniques trying to get around the fact that Java is a monolithic, statically typed, compiled, OO environment. It's not a Golden Hammer!”I asked him about the keys to running a good Java User Group. “You need to have a ‘Why,’” he observed. “Many user groups know what they do (typically, events) and how they do it (the logistics), but what really drives users to join your group and to stay is to give them a purpose. For example, within the LJC we constantly talk about the ‘Why,’ which in our case is several whys:* Re-ignite the passion that developers have for their craft* Raise the bar of Java developers in London* We want developers to have a voice in deciding the future of Java* We want to inspire the next generation of tech leaders* To bring the disparate tech groups in London together* So we could learn from each other* We believe that the Java ecosystem forms a cornerstone of our society today -- we want to protect that for the futureLooking ahead to Java 8 Verburg expressed excitement about Lambdas. “I cannot wait for Lambdas,” he enthused. “Brian Goetz and his group are doing a great job, especially given some of the backwards compatibility that they have to maintain. It's going to remove a lot of boiler plate and yet maintain readability, plus enable massive scaling.”Check out Martijn Verburg at JavaOne if you get a chance, and, stay tuned for a longer interview yours truly did with Martijn to be publish on otn/java some time after JavaOne. Originally published on blogs.oracle.com/javaone.

  Read the article

• Talking JavaOne with Rock Star Martijn Verburg

  - by Janice J. Heiss

  JavaOne Rock Stars, conceived in 2005, are the top-rated speakers at each JavaOne Conference. They are awarded by their peers, who, through conference surveys, recognize them for their outstanding sessions and speaking ability. Over the years many of the world’s leading Java developers have been so recognized. Martijn Verburg has, in recent years, established himself as an important mover and shaker in the Java community. His “Diabolical Developer” session at the JavaOne 2011 Conference got people’s attention by identifying some of the worst practices Java developers are prone to engage in. Among other things, he is co-leader and organizer of the thriving London Java User Group (JUG) which has more than 2,500 members, co-represents the London JUG on the Executive Committee of the Java Community Process, and leads the global effort for the Java User Group “Adopt a JSR” and “Adopt OpenJDK” programs. Career highlights include overhauling technology stacks and SDLC practices at Mizuho International, mentoring Oracle on technical community management, and running off shore development teams for AIG. He is currently CTO at jClarity, a start-up focusing on automating optimization for Java/JVM related technologies, and Product Advisor at ZeroTurnaround. He co-authored, with Ben Evans, "The Well-Grounded Java Developer" published by Manning and, as a leading authority on technical team optimization, he is in high demand at major software conferences.Verburg is participating in five sessions, a busy man indeed. Here they are: CON6152 - Modern Software Development Antipatterns (with Ben Evans) UGF10434 - JCP and OpenJDK: Using the JUGs’ “Adopt” Programs in Your Group (with Csaba Toth) BOF4047 - OpenJDK Building and Testing: Case Study—Java User Group OpenJDK Bugathon (with Ben Evans and Cecilia Borg) BOF6283 - 101 Ways to Improve Java: Why Developer Participation Matters (with Bruno Souza and Heather Vancura-Chilson) HOL6500 - Finding and Solving Java Deadlocks (with Heinz Kabutz, Kirk Pepperdine, Ellen Kraffmiller and Henri Tremblay) When I asked Verburg about the biggest mistakes Java developers tend to make, he listed three: A lack of communication -- Software development is far more a social activity than a technical one; most projects fail because of communication issues and social dynamics, not because of a bad technical decision. Sadly, many developers never learn this lesson. No source control -- Developers simply storing code in local filesystems and emailing code in order to integrate Design-driven Design -- The need for some developers to cram every design pattern from the Gang of Four (GoF) book into their source code All of which raises the question: If these practices are so bad, why do developers engage in them? “I've seen a wide gamut of reasons,” said Verburg, who lists them as: * They were never taught at high school/university that their bad habits were harmful.* They weren't mentored in their first professional roles.* They've lost passion for their craft.* They're being deliberately malicious!* They think software development is a technical activity and not a social one.* They think that they'll be able to tidy it up later.A couple of key confusions and misconceptions beset Java developers, according to Verburg. “With Java and the JVM in particular I've seen a couple of trends,” he remarked. “One is that developers think that the JVM is a magic box that will clean up their memory, make their code run fast, as well as make them cups of coffee. The JVM does help in a lot of cases, but bad code can and will still lead to terrible results! The other trend is to try and force Java (the language) to do something it's not very good at, such as rapid web development. So you get a proliferation of overly complex frameworks, libraries and techniques trying to get around the fact that Java is a monolithic, statically typed, compiled, OO environment. It's not a Golden Hammer!”I asked him about the keys to running a good Java User Group. “You need to have a ‘Why,’” he observed. “Many user groups know what they do (typically, events) and how they do it (the logistics), but what really drives users to join your group and to stay is to give them a purpose. For example, within the LJC we constantly talk about the ‘Why,’ which in our case is several whys:* Re-ignite the passion that developers have for their craft* Raise the bar of Java developers in London* We want developers to have a voice in deciding the future of Java* We want to inspire the next generation of tech leaders* To bring the disparate tech groups in London together* So we could learn from each other* We believe that the Java ecosystem forms a cornerstone of our society today -- we want to protect that for the futureLooking ahead to Java 8 Verburg expressed excitement about Lambdas. “I cannot wait for Lambdas,” he enthused. “Brian Goetz and his group are doing a great job, especially given some of the backwards compatibility that they have to maintain. It's going to remove a lot of boiler plate and yet maintain readability, plus enable massive scaling.”Check out Martijn Verburg at JavaOne if you get a chance, and, stay tuned for a longer interview yours truly did with Martijn to be publish on otn/java some time after JavaOne.

  Read the article

• An Alphabet of Eponymous Aphorisms, Programming Paradigms, Software Sayings, Annoying Alliteration

  - by Brian Schroer

  Malcolm Anderson blogged about “Einstein’s Razor” yesterday, which reminded me of my favorite software development “law”, the name of which I can never remember. It took much Wikipedia-ing to find it (Hofstadter’s Law – see below), but along the way I compiled the following list: Amara’s Law: We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run. Brook’s Law: Adding manpower to a late software project makes it later. Clarke’s Third Law: Any sufficiently advanced technology is indistinguishable from magic. Law of Demeter: Each unit should only talk to its friends; don't talk to strangers. Einstein’s Razor: “Make things as simple as possible, but not simpler” is the popular paraphrase, but what he actually said was “It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience”, an overly complicated quote which is an obvious violation of Einstein’s Razor. (You can tell by looking at a picture of Einstein that the dude was hardly an expert on razors or other grooming apparati.) Finagle's Law of Dynamic Negatives: Anything that can go wrong, will—at the worst possible moment. - O'Toole's Corollary: The perversity of the Universe tends towards a maximum. Greenspun's Tenth Rule: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp. (Morris’s Corollary: “…including Common Lisp”) Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law. Issawi’s Omelet Analogy: One cannot make an omelet without breaking eggs - but it is amazing how many eggs one can break without making a decent omelet. Jackson’s Rules of Optimization: Rule 1: Don't do it. Rule 2 (for experts only): Don't do it yet. Kaner’s Caveat: A program which perfectly meets a lousy specification is a lousy program. Liskov Substitution Principle (paraphrased): Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it Mason’s Maxim: Since human beings themselves are not fully debugged yet, there will be bugs in your code no matter what you do. Nils-Peter Nelson’s Nil I/O Rule: The fastest I/O is no I/O.    Occam's Razor: The simplest explanation is usually the correct one. Parkinson’s Law: Work expands so as to fill the time available for its completion. Quentin Tarantino’s Pie Principle: “…you want to go home have a drink and go and eat pie and talk about it.” (OK, he was talking about movies, not software, but I couldn’t find a “Q” quote about software. And wouldn’t it be cool to write a program so great that the users want to eat pie and talk about it?) Raymond’s Rule: Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter.  Sowa's Law of Standards: Whenever a major organization develops a new system as an official standard for X, the primary result is the widespread adoption of some simpler system as a de facto standard for X. Turing’s Tenet: We shall do a much better programming job, provided we approach the task with a full appreciation of its tremendous difficulty, provided that we respect the intrinsic limitations of the human mind and approach the task as very humble programmers.  Udi Dahan’s Race Condition Rule: If you think you have a race condition, you don’t understand the domain well enough. These rules didn’t exist in the age of paper, there is no reason for them to exist in the age of computers. When you have race conditions, go back to the business and find out actual rules. Van Vleck’s Kvetching: We know about as much about software quality problems as they knew about the Black Plague in the 1600s. We've seen the victims' agonies and helped burn the corpses. We don't know what causes it; we don't really know if there is only one disease. We just suffer -- and keep pouring our sewage into our water supply. Wheeler’s Law: All problems in computer science can be solved by another level of indirection... Except for the problem of too many layers of indirection. Wheeler also said “Compatibility means deliberately repeating other people's mistakes.”. The Wrong Road Rule of Mr. X (anonymous): No matter how far down the wrong road you've gone, turn back. Yourdon’s Rule of Two Feet: If you think your management doesn't know what it's doing or that your organisation turns out low-quality software crap that embarrasses you, then leave. Zawinski's Law of Software Envelopment: Every program attempts to expand until it can read mail. Zawinski is also responsible for “Some people, when confronted with a problem, think 'I know, I'll use regular expressions.' Now they have two problems.” He once commented about X Windows widget toolkits: “Using these toolkits is like trying to make a bookshelf out of mashed potatoes.”

  Read the article

• SQL Developer Data Modeler v3.3 Early Adopter: Collaborative Design via Excel?

  - by thatjeffsmith

  As you may have heard last week, we have a new version of Oracle SQL Developer Data Modeler now available as an Early Adopter release. Version 3.3 has quite a few new features and I’ll be previewing them here. Today’s topic is our new Excel integration. It builds off of last week’s lesson: Search, so you may want to go read that first. They say it takes a village to raise a child. I say it takes a team to build a data model. You have your techie folks, your business folks, your in-betweeners, and your database geeks. Who gets to define how customers are represented and stored in your database? That data lives forever, so you better get it right from the beginning, or you’ll be living in a hacker’s paradise for years to come. Lots of good rantings, ravings, and advice on this topic in general on Karen Lopez’s (@datachick) blog. But let’s say you are the primary modeler on a project. You dutifully interview the business folks for their requirements. You sit down and start to model and think you’re pretty close. Now you need someone to confirm your assumptions and provide some feedback. Do you send your model over? Take a screenshot and blow it up on a whiteboard? Export to HTML and let them take a magic marker to their monitors? Or maybe you bite the bullet and install your modeling software on their desktops and take the hours or days required to train them up on how to use the the tool. Wouldn’t it be nice if they could just mark up their corrections in Excel and let you suck the updates back in? This is what we have started to build in Oracle SQL Developer Data Modeler. Let’s say you have a new table called ‘UT_STARTUPS.’ It looks a little something like this: A table in Oracle SQL Developer Data Modeler What I would like to do is have my team or co-worker review how I have defined those columns. Perhaps TIMESTAMP is overkill or maybe the column names themselves aren’t up to snuff. What I am going to do is now search for all the columns in my table, then export that to Excel. So do a search for UT_STARTUPS. Search, filter, then Report With the filter set to ‘Columns,’ if I do a report I’ll be only getting the columns that are resolving to my search term. So as long as my table name is unique in the model, I should get what I’m looking for. Here’s what I see when I click on the Report button: XLS or XLSX, either format is just fine I want to decide how the Column data is exported to Excel though, so I’m going to create a report template that I can use going forward. So click the ‘Manage’ button and setup a new template. I’m going to call mine ‘CollaborativeDevelopment.’ The templates allow me to define what properties are included in the reports. Once this is set, I’ll have the XLS file generated, and get to work Now let the Excel junkies do their stuff Note that not ALL of the report properties are update-able (yes, I made up a new word there) via Excel. We’ll have the full list of properties documented going forward, but in my Excel sheet, note that I can’t change the table name or the data types for the columns. I’m going to update some column names and supply ‘nice’ comments so the database users know what’s what. Here’s my input for the designer/architect/database dude: Be kind, please rew…use comments. Save the file, email it back to your modeler. Update the model from Excel That’s right, it’s a right mouse click from your model in the tree If everything goes right, you’ll see a nice confirmation message: It’s alive! Another to-do item on tap – making this dialog more informative. We’ll be showing exactly what in your model was updated from Excel. Let’s take another look at the model now Voila! Why are we doing this again? The goal is to reduce the number of round-trips from the modeler and the business process owner. One is used to working with Excel – why not allow them to mark up their changes in the tool they already know? This is an early adopter release and I anticipate this feature getting a good bit of tuning up before we release. Why don’t you download 3.3, give it a whirl, and let us know what you think?

  Read the article

• The ugly evolution of running a background operation in the context of an ASP.NET app

  - by Jeff

  If you’re one of the two people who has followed my blog for many years, you know that I’ve been going at POP Forums now for over almost 15 years. Publishing it as an open source app has been a big help because it helps me understand how people want to use it, and having it translated to six languages is pretty sweet. Despite this warm and fuzzy group hug, there has been an ugly hack hiding in there for years. One of the things we find ourselves wanting to do is hide some kind of regular process inside of an ASP.NET application that runs periodically. The motivation for this has always been that a lot of people simply don’t have a choice, because they’re running the app on shared hosting, or don’t otherwise have access to a box that can run some kind of regular background service. In POP Forums, I “solved” this problem years ago by hiding some static timers in an HttpModule. Truthfully, this works well as long as you don’t run multiple instances of the app, which in the cloud world, is always a possibility. With the arrival of WebJobs in Azure, I’m going to solve this problem. This post isn’t about that. The other little hacky problem that I “solved” was spawning a background thread to queue emails to subscribed users of the forum. This evolved quite a bit over the years, starting with a long running page to mail users in real-time, when I had only a few hundred. By the time it got into the thousands, or tens of thousands, I needed a better way. What I did is launched a new thread that read all of the user data in, then wrote a queued email to the database (as in, the entire body of the email, every time), with the properly formatted opt-out link. It was super inefficient, but it worked. Then I moved my biggest site using it, CoasterBuzz, to an Azure Website, and it stopped working. So let’s start with the first stupid thing I was doing. The new thread was simply created with delegate code inline. As best I can tell, Azure Websites are more aggressive about garbage collection, because that thread didn’t queue even one message. When the calling server response went out of scope, so went the magic background thread. Duh, all I had to do was move the thread to a private static variable in the class. That’s the way I was able to keep stuff running from the HttpModule. (And yes, I know this is still prone to failure, particularly if the app recycles. For as infrequently as it’s used, I have not, however, experienced this.) It was still failing, but this time I wasn’t sure why. It would queue a few dozen messages, then die. Running in Azure, I had to turn on the application logging and FTP in to see what was going on. That led me to a helper method I was using as delegate to build the unsubscribe links. The idea here is that I didn’t want yet another config entry to describe the base URL, appended with the right path that would match the routing table. No, I wanted the app to figure it out for you, so I came up with this little thing: public static string FullUrlHelper(this Controller controller, string actionName, string controllerName, object routeValues = null) { var helper = new UrlHelper(controller.Request.RequestContext); var requestUrl = controller.Request.Url; if (requestUrl == null) return String.Empty; var url = requestUrl.Scheme + "://"; url += requestUrl.Host; url += (requestUrl.Port != 80 ? ":" + requestUrl.Port : ""); url += helper.Action(actionName, controllerName, routeValues); return url; } And yes, that should have been done with a string builder. This is useful for sending out the email verification messages, too. As clever as I thought I was with this, I was using a delegate in the admin controller to format these unsubscribe links for tens of thousands of users. I passed that delegate into a service class that did the email work: Func<User, string> unsubscribeLinkGenerator = user => this.FullUrlHelper("Unsubscribe", AccountController.Name, new { id = user.UserID, key = _profileService.GetUnsubscribeHash(user) }); _mailingListService.MailUsers(subject, body, htmlBody, unsubscribeLinkGenerator); Cool, right? Actually, not so much. If you look back at the helper, this delegate then will depend on the controller context to learn the routing and format for the URL. As you might have guessed, those things were turning null after a few dozen formatted links, when the original request to the admin controller went away. That this wasn’t already happening on my dedicated server is surprising, but again, I understand why the Azure environment might be eager to reclaim a thread after servicing the request. It’s already inefficient that I’m building the entire email for every user, but going back to check the routing table for the right link every time isn’t a win either. I put together a little hack to look up one generic URL, and use that as the basis for a string format. If you’re wondering why I didn’t just use the curly braces up front, it’s because they get URL formatted: var baseString = this.FullUrlHelper("Unsubscribe", AccountController.Name, new { id = "--id--", key = "--key--" }); baseString = baseString.Replace("--id--", "{0}").Replace("--key--", "{1}"); Func unsubscribeLinkGenerator = user => String.Format(baseString, user.UserID, _profileService.GetUnsubscribeHash(user)); _mailingListService.MailUsers(subject, body, htmlBody, unsubscribeLinkGenerator); And wouldn’t you know it, the new solution works just fine. It’s still kind of hacky and inefficient, but it will work until this somehow breaks too.

  Read the article

• Gene Hunt Says:

  - by BizTalk Visionary

  "She's as nervous as a very small nun at a penguin shoot"   "He's got fingers in more pies than a leper on a cookery course" "You so much as belch out of line and I'll have your scrotum on a barbed wire plate" "Let's go play slappyface" "your surrounded by armed barstewards" “Right, get out and find this murdering scum right now!” [pause] “Scratch that, we start 9am sharp tomorrow, it's beer-o-clock.” "So then Cartwright, you're such a good Detective.... Go and Detect me a packet of Garibaldies" "You're not the one who is going to have to knit himself a new arsehole after 25 years of aggressive male love in prison" “A dream for me is Diana Dors and a bottle of chip fat." “A dream for me is Diana Dors and a bottle of chip fat." “They reckon you've got concussion - but personally, I couldn't give a tart's furry cup if half your brains are falling out. Don't ever waltz into my kingdom playing king of the jungle.” “You great... soft... sissy... girlie... nancy... french... bender... Man-United supporting POOF!!” “Drugs eh? What's the point. They make you forget, make you talk funny, make you see things that aren't there. My old grandma got all of that for free when she had a stroke.” “He's Dead! It's quite serious!” “Fanny in the flat...Nice Work” “SoopaDoopa” “Tits in a Jumper!” “Drop your weapons! You are surrounded by armed bastards!” “It's 1973, almost dinnertime. I'm 'avin 'oops!” “Trust the Gene Genie!” “I wanna hump Britt Ekland...What're we gonna do...!” “Was that 'E' and you don't know the rest?! or you going 'Eeee, I Dunno'” “Good Girl! Prostate probe and no jelly. “ “Give over, it's nothing like Spain!” “I'll come over your houses and stamp on all your toys!” “The Wizard will sort it out. It's cos of the wonderful things he does” “Cartwright can jump up and down on his knackers!” “It's not a windup love, he really thinks like this!” “Women! You can't say two words to them” “I was thinking, maybe, a Berni Inn!” “If I wanted a bollocking for drinking too much...!” “Shhhh...hear that...that's the sound of this case being closed! “Chicken!? In a basket!?” “Seems a large quantity of cocaine...” “You probably thought he kept his cock in his keks!” “The tail-end of Rays demotion speech!” “Stephen Warren is gay!?” “You're a smart boy, use your initiative!” “Don't be such a Jessie!” “I find the idea of a bird brushing her teeth...!” “Never been tempted to the Magic talcum powder?” “Make sure she's got nice tits!” “You're more likely to find an ostrich with a plum up it's arse!” “Drink this lot under the table and have a pint on the way home!” “Never be a female Prime Minister!” “Pub? Pub! pub!.....Pub!” “Thou shalt not suck off rent boys!” “The number for the special clinic is on the notice board!” “If me uncle had tits, would he be me auntie!” “Got your vicars in a twist!” “We Done?!” “Your mates got balls...If they were any bigger he'd need a wheelbarrow!” “The Ending - from 'I want to go home' to the end music.”

  Read the article

• How to restore your production database without needing additional storage

  - by David Atkinson

  Production databases can get very large. This in itself is to be expected, but when a copy of the database is needed the database must be restored, requiring additional and costly storage.  For example, if you want to give each developer a full copy of your production server, you’ll need n times the storage cost for your n-developer team. The same is true for any test databases that are created during the course of your project lifecycle. If you’ve read my previous blog posts, you’ll be aware that I’ve been focusing on the database continuous integration theme. In my CI setup I create a “production”-equivalent database directly from its source control representation, and use this to test my upgrade scripts. Despite this being a perfectly valid and practical thing to do as part of a CI setup, it’s not the exact equivalent to running the upgrade script on a copy of the actual production database. So why shouldn’t I instead simply restore the most recent production backup as part of my CI process? There are two reasons why this would be impractical. 1. My CI environment isn’t an exact copy of my production environment. Indeed, this would be the case in a perfect world, and it is strongly recommended as a good practice if you follow Jez Humble and David Farley’s “Continuous Delivery” teachings, but in practical terms this might not always be possible, especially where storage is concerned. It may just not be possible to restore a huge production database on the environment you’ve been allotted. 2. It’s not just about the storage requirements, it’s also the time it takes to do the restore. The whole point of continuous integration is that you are alerted as early as possible whether the build (yes, the database upgrade script counts!) is broken. If I have to run an hour-long restore each time I commit a change to source control I’m just not going to get the feedback quickly enough to react. So what’s the solution? Red Gate has a technology, SQL Virtual Restore, that is able to restore a database without using up additional storage. Although this sounds too good to be true, the explanation is quite simple (although I’m sure the technical implementation details under the hood are quite complex!) Instead of restoring the backup in the conventional sense, SQL Virtual Restore will effectively mount the backup using its HyperBac technology. It creates a data and log file, .vmdf, and .vldf, that becomes the delta between the .bak file and the virtual database. This means that both read and write operations are permitted on a virtual database as from SQL Server’s point of view it is no different from a conventional database. Instead of doubling the storage requirements upon a restore, there is no ‘duplicate’ storage requirements, other than the trivially small virtual log and data files (see illustration below). The benefit is magnified the more databases you mount to the same backup file. This technique could be used to provide a large development team a full development instance of a large production database. It is also incredibly easy to set up. Once SQL Virtual Restore is installed, you simply run a conventional RESTORE command to create the virtual database. This is what I have running as part of a nightly “release test” process triggered by my CI tool. RESTORE DATABASE WidgetProduction_Virtual FROM DISK=N'D:\VirtualDatabase\WidgetProduction.bak' WITH MOVE N'WidgetProduction' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_WidgetProduction_Virtual.vmdf', MOVE N'WidgetProduction_log' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_log_WidgetProduction_Virtual.vldf', NORECOVERY, STATS=1, REPLACE GO RESTORE DATABASE WidgetProduction_Virtual WITH RECOVERY   Note the only change from what you would do normally is the naming of the .vmdf and .vldf files. SQL Virtual Restore intercepts this by monitoring the extension and applies its magic, ensuring the ‘virtual’ restore happens rather than the conventional storage-heavy restore. My automated release test then applies the upgrade scripts to the virtual production database and runs some validation tests, giving me confidence that were I to run this on production for real, all would go smoothly. For illustration, here is my 8Gb production database: And its corresponding backup file: Here are the .vldf and .vmdf files, which represent the only additional used storage for the new database following the virtual restore.   The beauty of this product is its simplicity. Once it is installed, the interaction with the backup and virtual database is exactly the same as before, as the clever stuff is being done at a lower level. SQL Virtual Restore can be downloaded as a fully functional 14-day trial. Technorati Tags: SQL Server

  Read the article

• How to restore your production database without needing additional storage

  - by David Atkinson

  Production databases can get very large. This in itself is to be expected, but when a copy of the database is needed the database must be restored, requiring additional and costly storage.  For example, if you want to give each developer a full copy of your production server, you'll need n times the storage cost for your n-developer team. The same is true for any test databases that are created during the course of your project lifecycle. If you've read my previous blog posts, you'll be aware that I've been focusing on the database continuous integration theme. In my CI setup I create a "production"-equivalent database directly from its source control representation, and use this to test my upgrade scripts. Despite this being a perfectly valid and practical thing to do as part of a CI setup, it's not the exact equivalent to running the upgrade script on a copy of the actual production database. So why shouldn't I instead simply restore the most recent production backup as part of my CI process? There are two reasons why this would be impractical. 1. My CI environment isn't an exact copy of my production environment. Indeed, this would be the case in a perfect world, and it is strongly recommended as a good practice if you follow Jez Humble and David Farley's "Continuous Delivery" teachings, but in practical terms this might not always be possible, especially where storage is concerned. It may just not be possible to restore a huge production database on the environment you've been allotted. 2. It's not just about the storage requirements, it's also the time it takes to do the restore. The whole point of continuous integration is that you are alerted as early as possible whether the build (yes, the database upgrade script counts!) is broken. If I have to run an hour-long restore each time I commit a change to source control I'm just not going to get the feedback quickly enough to react. So what's the solution? Red Gate has a technology, SQL Virtual Restore, that is able to restore a database without using up additional storage. Although this sounds too good to be true, the explanation is quite simple (although I'm sure the technical implementation details under the hood are quite complex!) Instead of restoring the backup in the conventional sense, SQL Virtual Restore will effectively mount the backup using its HyperBac technology. It creates a data and log file, .vmdf, and .vldf, that becomes the delta between the .bak file and the virtual database. This means that both read and write operations are permitted on a virtual database as from SQL Server's point of view it is no different from a conventional database. Instead of doubling the storage requirements upon a restore, there is no 'duplicate' storage requirements, other than the trivially small virtual log and data files (see illustration below). The benefit is magnified the more databases you mount to the same backup file. This technique could be used to provide a large development team a full development instance of a large production database. It is also incredibly easy to set up. Once SQL Virtual Restore is installed, you simply run a conventional RESTORE command to create the virtual database. This is what I have running as part of a nightly "release test" process triggered by my CI tool. RESTORE DATABASE WidgetProduction_virtual FROM DISK=N'C:\WidgetWF\ProdBackup\WidgetProduction.bak' WITH MOVE N'WidgetProduction' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_WidgetProduction_Virtual.vmdf', MOVE N'WidgetProduction_log' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_log_WidgetProduction_Virtual.vldf', NORECOVERY, STATS=1, REPLACE GO RESTORE DATABASE mydatabase WITH RECOVERY   Note the only change from what you would do normally is the naming of the .vmdf and .vldf files. SQL Virtual Restore intercepts this by monitoring the extension and applies its magic, ensuring the 'virtual' restore happens rather than the conventional storage-heavy restore. My automated release test then applies the upgrade scripts to the virtual production database and runs some validation tests, giving me confidence that were I to run this on production for real, all would go smoothly. For illustration, here is my 8Gb production database: And its corresponding backup file: Here are the .vldf and .vmdf files, which represent the only additional used storage for the new database following the virtual restore.   The beauty of this product is its simplicity. Once it is installed, the interaction with the backup and virtual database is exactly the same as before, as the clever stuff is being done at a lower level. SQL Virtual Restore can be downloaded as a fully functional 14-day trial. Technorati Tags: SQL Server

  Read the article

• Optimizing collision engine bottleneck

  - by Vittorio Romeo

  Foreword: I'm aware that optimizing this bottleneck is not a necessity - the engine is already very fast. I, however, for fun and educational purposes, would love to find a way to make the engine even faster. I'm creating a general-purpose C++ 2D collision detection/response engine, with an emphasis on flexibility and speed. Here's a very basic diagram of its architecture: Basically, the main class is World, which owns (manages memory) of a ResolverBase*, a SpatialBase* and a vector<Body*>. SpatialBase is a pure virtual class which deals with broad-phase collision detection. ResolverBase is a pure virtual class which deals with collision resolution. The bodies communicate to the World::SpatialBase* with SpatialInfo objects, owned by the bodies themselves. There currenly is one spatial class: Grid : SpatialBase, which is a basic fixed 2D grid. It has it's own info class, GridInfo : SpatialInfo. Here's how its architecture looks: The Grid class owns a 2D array of Cell*. The Cell class contains two collection of (not owned) Body*: a vector<Body*> which contains all the bodies that are in the cell, and a map<int, vector<Body*>> which contains all the bodies that are in the cell, divided in groups. Bodies, in fact, have a groupId int that is used for collision groups. GridInfo objects also contain non-owning pointers to the cells the body is in. As I previously said, the engine is based on groups. Body::getGroups() returns a vector<int> of all the groups the body is part of. Body::getGroupsToCheck() returns a vector<int> of all the groups the body has to check collision against. Bodies can occupy more than a single cell. GridInfo always stores non-owning pointers to the occupied cells. After the bodies move, collision detection happens. We assume that all bodies are axis-aligned bounding boxes. How broad-phase collision detection works: Part 1: spatial info update For each Body body: Top-leftmost occupied cell and bottom-rightmost occupied cells are calculated. If they differ from the previous cells, body.gridInfo.cells is cleared, and filled with all the cells the body occupies (2D for loop from the top-leftmost cell to the bottom-rightmost cell). body is now guaranteed to know what cells it occupies. For a performance boost, it stores a pointer to every map<int, vector<Body*>> of every cell it occupies where the int is a group of body->getGroupsToCheck(). These pointers get stored in gridInfo->queries, which is simply a vector<map<int, vector<Body*>>*>. body is now guaranteed to have a pointer to every vector<Body*> of bodies of groups it needs to check collision against. These pointers are stored in gridInfo->queries. Part 2: actual collision checks For each Body body: body clears and fills a vector<Body*> bodiesToCheck, which contains all the bodies it needs to check against. Duplicates are avoided (bodies can belong to more than one group) by checking if bodiesToCheck already contains the body we're trying to add. const vector<Body*>& GridInfo::getBodiesToCheck() { bodiesToCheck.clear(); for(const auto& q : queries) for(const auto& b : *q) if(!contains(bodiesToCheck, b)) bodiesToCheck.push_back(b); return bodiesToCheck; } The GridInfo::getBodiesToCheck() method IS THE BOTTLENECK. The bodiesToCheck vector must be filled for every body update because bodies could have moved meanwhile. It also needs to prevent duplicate collision checks. The contains function simply checks if the vector already contains a body with std::find. Collision is checked and resolved for every body in bodiesToCheck. That's it. So, I've been trying to optimize this broad-phase collision detection for quite a while now. Every time I try something else than the current architecture/setup, something doesn't go as planned or I make assumption about the simulation that later are proven to be false. My question is: how can I optimize the broad-phase of my collision engine maintaining the grouped bodies approach? Is there some kind of magic C++ optimization that can be applied here? Can the architecture be redesigned in order to allow for more performance? Actual implementation: SSVSCollsion Body.h, Body.cpp World.h, World.cpp Grid.h, Grid.cpp Cell.h, Cell.cpp GridInfo.h, GridInfo.cpp

  Read the article

< Previous Page | 56 57 58 59 60 61 62 63 64 65 66 67  | Next Page >