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  • Problems with Net::FTP slowing down

    - by c0bra
    I'm running into an issue with using Net::FTP (latest version 2.77) to transfer files to a remote host where a process is waiting to take the file and feed into some other system. The remote process does this every 5 minutes but ignores files that were modified in the last 0.2 seconds (that's right, 1/5th of a second). The problem is that for some reason the transfer seems to halt or slow down a bit and no data is transferred for several seconds and during this time the process picks up the incomplete file and removes it. The weird thing is that manually using the ftp binary the file seems to transfer fine. I've tried messing with all of the Net::FTP switches (Active/Passive, different Blocksizes) and nothing seems to help. What's also weird is that the file seems to transfer fairly quickly at first and on occasion a bit into the transfer. Like 300-500k will go up immediately, but then it slows down to where the file size is only increasing by 2,896 bytes every several seconds. It doesn't seem to happen when I try sending the file to a different remote host, but since a regular manual ftp transfer works with this host I don't know what to think. Some combination of Net::FTP and possibly a slow or wonky connection?

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  • Application that will identify percentage of your system disk bandwidth used on a user-application by user-application basis?

    - by Warren P
    I always (subjectively) feel my computer is far too slow (however fast it is), and so I'm always looking for ways to measure and understand what my computer is actually doing, that is making it seem "slow" to me. It has been my observation that my software-developer workload is most often disk-bound (I am waiting for Disk I/O) more than CPU bound. What has made it worse, is that I am using a corporate PC that has in-memory active-scanning anti-virus software that I do not have control over, and also some IT department mandated services that seem to suck up a lot of available hard-disk bandwidth. The best tool I have seen (in Windows 7) is the Resource Monitor which I usually acess from the button in the task Manager. The disk IO page, however, seems to label Disk Activity at a very low level (for example, showing the Volume Shadow Storage, which is flushing information obviously written by something ELSE other than VSS itself, and then writes to Pagefile.sys, which are obviously due to Virtual Memory faults in some application). What I would like to know is if a utility exists that can add up all direct disk input and output by user-level process, or find the process or service that caused VM or VSS activity. In that way, I hope, you could establish a real idea of how much of your computer's precious disk subsystem bandwidth is attributable to a particular application. here's a scenario: MyApp.exe writes 100k/s and reads 100k/s directly. VSS ends up writing another 100k/s. pagefaults caused inside MyApp.exe cause another 100k/s of writes. So the total "cost" of MyApp.exe running, during a period of time (let's say 1 second) is 400k/s, whereas you can only directly observe half of that, in Resource Monitor. Is there a smarter disk-IO watching piece of software I can use?

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  • 100% CPU when doing 4 or more concurrent requests with Magento

    - by pancake
    Currently I'm having trouble with a server running Magento, it's unbelievably slow. It's a VPS with a few Magento installations on it used for development, so I'm the only one using them. When I do 4 request all 2 seconds after each other I'm finished in 10 seconds. Slow, but still within the limits of my patience. When I do 4 "concurrent" requests, however (opening 4 tabs in a row, very quickly) all four cores go to 100% and stay there for like a minute. How is this possible? I know that there are a lot of possibilities here, so any tips on how to make an Apache/PHP server go faster are also welcome. It used to go a lot faster before, and I've also tried APC, but it kept causing problems (PHP errors, something with memory pools) so I've disabled it. By the way, the Magento cache is off and compiling is also off. I know this makes Magento slower than usual, but I don't think a 60 second response time is normal for any Magento installation. Virtual hardware: 4 Cores and 4096MB RAM Swap is never used (checked with htop) 100GB disk space, of which 10% is in use Software: Debian 6 DirectAdmin and apache custombuild PHP 5.2.17 (CLI) If you need more info, please tell me how to get it, because I probably don't know how. I do know how to use the command line in linux and the usage of quite a few commands, but my experience with managing a server is limited.

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  • Good Hosting Providers With Zend Framework Support [closed]

    - by manyxcxi
    I currently use ixwebhosting for my hosting services. They're cheap and work (most of the time). The databases are horribly slow, the servers are horribly slow, and their support (though usually prompt) is tough to deal with. That being said, they're cheap, I've got like 20 domains hosted in my account, none of them are high volume, and they work JUST good enough- until today. This isn't meant to be a condemnation of ixwh though. Their prices are very low for what they do offer and most things work just fine, most of the time. I need to be able to host web apps written with Zend Framework in a fairly easy fashion. The server performance can't be worse than what I've already had (a pretty low hurdle to clear), and I don't want to spend $30/mo. These are not money making websites- they're projects. My requirements are PHP 5.3, ZF support, MySQL databases, multiple domains- not much. Who should I look at, and who should I look out for?

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  • Connect USB hard drive to wireless router on RJ45 port? Possible?

    - by lawphotog
    just a quick story behind. I was trying to set up wireless networked hard drive at home. My wireless router doesn't take USB. I am considering few options. First i was considering to get something like WD My Cloud. My router is an old one provided by service provider. It only has 10/100 Ethernet. WD My Cloud has Gigabit interface. So unless i changed a new router, data transfer will be slow. So upgrading the router is a must if i want fast transfer speed. Plus I already own an external hard drive with USB 3.0 interface. So if I get a router like Netgear D6300, i can get a decent speed wireless shared drive at home. And i can use my existing HDD instead of WD My Cloud. But the router isn't cheap so I am saving up for that. In the meantime I found out the existence of USB to RJ45 adaptor. I read the reviews and some say it works for them and for some don't. They didn't really say what they were trying to do so I'm confused. So if i bought an adaptor like this, can i connect my existing HDD (USB) with my existing router (RJ45) and use it as a shared drive for data transfer? I know it will be slow as the adaptor will only have USB 2.0 and 10/100 for Ethernet. But it's fine as it's for temporary until i got my new router.

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  • Screen recording in Windows 8 makes PC unusable?

    - by Skadier
    OS used: Windows 8 Pro x64 Hi there, I got a weird problem. I tried to record my screen using different screen recording applications like Camtasia7, Hypercam, and some others. So if I hit "record" everything works fine for about 3-4 seconds. Then the PC slows down heavily caused by extremly high IO usage. The PC gets nearly unusable and laggs like hell. I can't switch applications, can't get TaskManager with Ctrl+Alt+Del, or something else without waiting 1-3 Minutes. After about 5-8 Minutes and a bit of luck I am sometimes able to end the process of the recorder and IO calms down very slow(100% IO lasts for about 2 Minutes before becoming normal). I don't know why this happens. Screen recorders that support Windows 8 aren't out afaik but at least Camtasia7 worked with Windows 8 Developer Preview and Windows 8 Release Preview (only had to change record method to .avi). No slow downs or something else. Is there anyone out there who knows this problem too? Is there maybe a solution to this problem?

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  • jQueryUI Tabs: how to keep them on a single line?

    - by Andi
    Hi all, Maybe my question is wired: is there a way to prevent jQueryUI tabs from floating if browser window is too small? Explanation: I have a simple horizontal tab using CSS only. The content is floating but not the tabs. Important: there is no width set manually, the current width is taken automatically. Here is the code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <style type="text/css"> #tabs ul { white-space: nowrap; } #tabs ul li { display: inline; white-space: nowrap; } </style> <title>Tabs-CSS</title> </head> <body> <div class="demo"> <div id="tabs"> <ul> <li><a href="#tabs-1">Preloaded</a></li> <li><a href="ajax/content1.html">Tab 1</a></li> <li><a href="ajax/content2.html">Tab 2</a></li> <li><a href="ajax/content3-slow.php">Tab 3 (slow)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> </ul> <div id="tabs-1"> <p>Proin elit arcu, rutrum commodo, vehicula tempus, commodo a, risus. Curabitur nec arcu. Donec sollicitudin mi sit amet mauris. Nam elementum quam ullamcorper ante. Etiam aliquet massa et lorem. Mauris dapibus lacus auctor risus. Aenean tempor ullamcorper leo. Vivamus sed magna quis ligula eleifend adipiscing. Duis orci. Aliquam sodales tortor vitae ipsum. Aliquam nulla. Duis aliquam molestie erat. Ut et mauris vel pede varius sollicitudin. Sed ut dolor nec orci tincidunt interdum. Phasellus ipsum. Nunc tristique tempus lectus.</p> </div> </div> </div> </body> </html> This is exactly what I want. Next step: add jQueryUI Tab as unobtrusive Javascript. For example like this: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" type="text/javascript"></script> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.1/jquery-ui.min.js"></script> <link type="text/css" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/themes/ui-lightness/jquery-ui.css" rel="stylesheet"/> <style type="text/css"> #tabs ul { white-space: nowrap; } #tabs ul li { display: inline; white-space: nowrap; } </style> <title>Tabs-CSS</title> </head> <body> <div class="demo"> <div id="tabs"> <ul> <li><a href="#tabs-1">Preloaded</a></li> <li><a href="ajax/content1.html">Tab 1</a></li> <li><a href="ajax/content2.html">Tab 2</a></li> <li><a href="ajax/content3-slow.php">Tab 3 (slow)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> </ul> <div id="tabs-1"> <p>Proin elit arcu, rutrum commodo, vehicula tempus, commodo a, risus. Curabitur nec arcu. Donec sollicitudin mi sit amet mauris. Nam elementum quam ullamcorper ante. Etiam aliquet massa et lorem. Mauris dapibus lacus auctor risus. Aenean tempor ullamcorper leo. Vivamus sed magna quis ligula eleifend adipiscing. Duis orci. Aliquam sodales tortor vitae ipsum. Aliquam nulla. Duis aliquam molestie erat. Ut et mauris vel pede varius sollicitudin. Sed ut dolor nec orci tincidunt interdum. Phasellus ipsum. Nunc tristique tempus lectus.</p> </div> </div> </div> <script type="text/javascript"> //<![CDATA[ $(function() { $("#tabs").tabs({ ajaxOptions: { error: function(xhr, status, index, anchor) { $(anchor.hash).html("Couldn't load this tab. We'll try to fix this as soon as possible. If this wouldn't be a demo."); }, } }); }); $(function() { $("#innertabs").tabs({ ajaxOptions: { error: function(xhr, status, index, anchor) { $(anchor.hash).html("Couldn't load this tab. We'll try to fix this as soon as possible. If this wouldn't be a demo."); } } }); }); //]]> </script> </body> </html> Now I can see that the tabbar floats on minimizing the browser window. And there are some ugly effect with the tabs jumping around. My main questions is: can I avoid floating the tabbar and keep all tabs on one single line? Kind regards, Andi

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  • jQueryUI Tabs: how too keep them on a single line?

    - by Andi
    Hi all, Maybe my question is wired: is there a way to prevent jQueryUI tabs from floating if browser window is too small? Explanation: I have a simple horizontal tab using CSS only. The content is floating but not the tabs. Important: there is no width set manually, the current width is taken automatically. Here is the code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <style type="text/css"> #tabs ul { white-space: nowrap; } #tabs ul li { display: inline; white-space: nowrap; } </style> <title>Tabs-CSS</title> </head> <body> <div class="demo"> <div id="tabs"> <ul> <li><a href="#tabs-1">Preloaded</a></li> <li><a href="ajax/content1.html">Tab 1</a></li> <li><a href="ajax/content2.html">Tab 2</a></li> <li><a href="ajax/content3-slow.php">Tab 3 (slow)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> </ul> <div id="tabs-1"> <p>Proin elit arcu, rutrum commodo, vehicula tempus, commodo a, risus. Curabitur nec arcu. Donec sollicitudin mi sit amet mauris. Nam elementum quam ullamcorper ante. Etiam aliquet massa et lorem. Mauris dapibus lacus auctor risus. Aenean tempor ullamcorper leo. Vivamus sed magna quis ligula eleifend adipiscing. Duis orci. Aliquam sodales tortor vitae ipsum. Aliquam nulla. Duis aliquam molestie erat. Ut et mauris vel pede varius sollicitudin. Sed ut dolor nec orci tincidunt interdum. Phasellus ipsum. Nunc tristique tempus lectus.</p> </div> </div> </div> </body> </html> This is exactly what I want. Next step: add jQueryUI Tab as unobtrusive Javascript. For example like this: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" type="text/javascript"></script> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.1/jquery-ui.min.js"></script> <link type="text/css" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/themes/ui-lightness/jquery-ui.css" rel="stylesheet"/> <style type="text/css"> #tabs ul { white-space: nowrap; } #tabs ul li { display: inline; white-space: nowrap; } </style> <title>Tabs-CSS</title> </head> <body> <div class="demo"> <div id="tabs"> <ul> <li><a href="#tabs-1">Preloaded</a></li> <li><a href="ajax/content1.html">Tab 1</a></li> <li><a href="ajax/content2.html">Tab 2</a></li> <li><a href="ajax/content3-slow.php">Tab 3 (slow)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> <li><a href="ajax/content4-broken.php">Tab 4 (broken)</a></li> </ul> <div id="tabs-1"> <p>Proin elit arcu, rutrum commodo, vehicula tempus, commodo a, risus. Curabitur nec arcu. Donec sollicitudin mi sit amet mauris. Nam elementum quam ullamcorper ante. Etiam aliquet massa et lorem. Mauris dapibus lacus auctor risus. Aenean tempor ullamcorper leo. Vivamus sed magna quis ligula eleifend adipiscing. Duis orci. Aliquam sodales tortor vitae ipsum. Aliquam nulla. Duis aliquam molestie erat. Ut et mauris vel pede varius sollicitudin. Sed ut dolor nec orci tincidunt interdum. Phasellus ipsum. Nunc tristique tempus lectus.</p> </div> </div> </div> <script type="text/javascript"> //<![CDATA[ $(function() { $("#tabs").tabs({ ajaxOptions: { error: function(xhr, status, index, anchor) { $(anchor.hash).html("Couldn't load this tab. We'll try to fix this as soon as possible. If this wouldn't be a demo."); }, } }); }); $(function() { $("#innertabs").tabs({ ajaxOptions: { error: function(xhr, status, index, anchor) { $(anchor.hash).html("Couldn't load this tab. We'll try to fix this as soon as possible. If this wouldn't be a demo."); } } }); }); //]]> </script> </body> </html> Now I can see that the tabbar floats on minimizing the browser window. And there are some ugly effect with the tabs jumping around. My main questions is: can I avoid floating the tabbar and keep all tabs on one single line? Kind regards, Andi

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  • Optimizing MySQL for small VPS

    - by Chris M
    I'm trying to optimize my MySQL config for a verrry small VPS. The VPS is also running NGINX/PHP-FPM and Magento; all with a limit of 250MB of RAM. This is an output of MySQL Tuner... -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.1.41-3ubuntu12.8 [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 1M (Tables: 14) [--] Data in InnoDB tables: 29M (Tables: 301) [--] Data in MEMORY tables: 1M (Tables: 17) [!!] Total fragmented tables: 301 -------- Security Recommendations ------------------------------------------- [OK] All database users have passwords assigned -------- Performance Metrics ------------------------------------------------- [--] Up for: 2d 11h 14m 58s (1M q [8.038 qps], 33K conn, TX: 2B, RX: 618M) [--] Reads / Writes: 83% / 17% [--] Total buffers: 122.0M global + 8.6M per thread (100 max threads) [!!] Maximum possible memory usage: 978.2M (404% of installed RAM) [OK] Slow queries: 0% (37/1M) [OK] Highest usage of available connections: 6% (6/100) [OK] Key buffer size / total MyISAM indexes: 32.0M/282.0K [OK] Key buffer hit rate: 99.7% (358K cached / 1K reads) [OK] Query cache efficiency: 83.4% (1M cached / 1M selects) [!!] Query cache prunes per day: 48301 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 144K sorts) [OK] Temporary tables created on disk: 13% (27K on disk / 203K total) [OK] Thread cache hit rate: 99% (6 created / 33K connections) [!!] Table cache hit rate: 0% (32 open / 51K opened) [OK] Open file limit used: 1% (20/1K) [OK] Table locks acquired immediately: 99% (1M immediate / 1M locks) [!!] InnoDB data size / buffer pool: 29.2M/8.0M -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance Reduce your overall MySQL memory footprint for system stability Enable the slow query log to troubleshoot bad queries Increase table_cache gradually to avoid file descriptor limits Variables to adjust: *** MySQL's maximum memory usage is dangerously high *** *** Add RAM before increasing MySQL buffer variables *** query_cache_size (> 64M) table_cache (> 32) innodb_buffer_pool_size (>= 29M) and this is the config. # # The MySQL database server configuration file. # # You can copy this to one of: # - "/etc/mysql/my.cnf" to set global options, # - "~/.my.cnf" to set user-specific options. # # One can use all long options that the program supports. # Run program with --help to get a list of available options and with # --print-defaults to see which it would actually understand and use. # # For explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # This will be passed to all mysql clients # It has been reported that passwords should be enclosed with ticks/quotes # escpecially if they contain "#" chars... # Remember to edit /etc/mysql/debian.cnf when changing the socket location. [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. Both versions are currently parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] # # * Basic Settings # # # * IMPORTANT # If you make changes to these settings and your system uses apparmor, you may # also need to also adjust /etc/apparmor.d/usr.sbin.mysqld. # user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. bind-address = 127.0.0.1 # # * Fine Tuning # key_buffer = 32M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 sort_buffer_size = 4M read_buffer_size = 4M myisam_sort_buffer_size = 16M # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP max_connections = 100 table_cache = 32 tmp_table_size = 128M #thread_concurrency = 10 # # * Query Cache Configuration # #query_cache_limit = 1M query_cache_type = 1 query_cache_size = 64M # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. # As of 5.1 you can enable the log at runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 log_error = /var/log/mysql/error.log # Here you can see queries with especially long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log expire_logs_days = 10 max_binlog_size = 100M #binlog_do_db = include_database_name #binlog_ignore_db = include_database_name # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 16M # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ The site contains 1 wordpress site,so lots of MYISAM but mostly static content as its not changing all that often (A wordpress cache plugin deals with this). And the Magento Site which consists of a lot of InnoDB tables, some MyISAM and some INMEMORY. The "read" side seems to be running pretty well with a mass of optimizations I've used on Magento, the NGINX setup and PHP-FPM + XCACHE. I'd love to have a kick in the right direction with the MySQL config so I'm not blindly altering it based on the MySQLTuner without understanding what I'm changing. Thanks

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  • What do I need to write a small game on Linux?

    - by Michas
    I want to make a simple game: 2d, single-player, without tons of animations and special effects. I am not interested in ready to use game engines, I want to learn to write some code in a quite universal language. I am using Linux (AMD64) and looking for something easy with nice library for games. I do not want to mix few languages, most of them are in fact fast enough themselves for my needs. Cross platform would be an advantage, however all I need is a good Linux support. I have been considering few solutions. Ruby + Language looks very nice. + I am going to learn Ruby. - I am afraid I can have problems with additional libraries. - This thread about game libraries for Ruby could be longer. SDL + C + It is used for games. + It is very easy to set up. + There is a lot of additional libraries. + It is cross-platform. - The solution is quite low level. - The language is sometimes quite hard to read. QT + C++ + It is very easy to set up. + The standard QT libraries supports everything I can possibly need. + It is cross-platform. + The documentation is good. - The compilation is slow. - The language looks horrible. - The size of standard QT libraries is too big to comprehend. Environment of web browser + I am going to learn something more about this environment. + It is somewhat used for games. + It is quite cross-platform. - It would be too much experimental. Java + It is used for games. + The standard Java libraries supports everything I can possibly need. + It is cross-platform. - It is quite hard to set up. - The size of standard Java libraries is too big to comprehend. - The source code in Java could look better. - I think I do not want to learn Java. Google Go + I am going to learn Google Go. - There is big problem with libraries. - The solution would be quite low level. Python + It looks some people do games in Python, according to this thread. + It looks there are probably more libraries than for Ruby. - The Ruby language looks better. - I think I do not want to learn Python. C++ + something else + It is used for games. + It would be probably cross-platform. + There is a lot of libraries. - I do not need C++ extensions over C. - Compilation could be slow, there are fast compilers for C, not for C++. Haskell + I am going to learn Haskell. - Many things about programming computer games looks too much imperative. - It looks I can have some problems with libraries. - Compilation (GHC) looks slow. There is probably something more to consider. Does anyone have experience in making small games for Linux in non mainstream solutions? Does anyone have an advice for me?

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  • Improving TCP performance over a gigabit network lots of connections and high traffic for storage and streaming services

    - by Linux Guy
    I have two servers, Both servers hardware Specification are Processor : Dual Processor RAM : over 128 G.B Hard disk : SSD Hard disk Outging Traffic bandwidth : 3 Gbps network cards speed : 10 Gbps Server A : for Encoding videos Server B : for storage videos andstream videos over web interface like youtube The inbound bandwidth between two servers is 10Gbps , the outbound bandwidth internet bandwidth is 500Mpbs Both servers using public ip addresses in public and private network Both servers transfer and connection on nginx port , and the server B used for streaming media , like youtube stream videos Both servers in same network , when i do ping from Server A to Server B i got high time latency above 1.0ms , the time range time=52.7 ms to time=215.7 ms - This is the output of iftop utility 353Mb 707Mb 1.04Gb 1.38Gb 1.73Gb mqqqqqqqqqqqqqqqqqqqqqqqqqqqvqqqqqqqqqqqqqqqqqqqqqqqqqqqvqqqqqqqqqqqqqqqqqqqqqqqqqqqvqqqqqqqqqqqqqqqqqqqqqqqqqqqvqqqqqqqqqqqqqqqqqqqqqqqqqqq server.example.com => ip.address 6.36Mb 4.31Mb 1.66Mb <= 158Kb 94.8Kb 35.1Kb server.example.com => ip.address 1.23Mb 4.28Mb 1.12Mb <= 17.1Kb 83.5Kb 21.9Kb server.example.com => ip.address 395Kb 3.89Mb 1.07Mb <= 6.09Kb 109Kb 28.6Kb server.example.com => ip.address 4.55Mb 3.83Mb 1.04Mb <= 55.6Kb 45.4Kb 13.0Kb server.example.com => ip.address 649Kb 3.38Mb 1.47Mb <= 9.00Kb 38.7Kb 16.7Kb server.example.com => ip.address 5.00Mb 3.32Mb 1.80Mb <= 65.7Kb 55.1Kb 29.4Kb server.example.com => ip.address 387Kb 3.13Mb 1.06Mb <= 18.4Kb 39.9Kb 15.0Kb server.example.com => ip.address 3.27Mb 3.11Mb 1.01Mb <= 81.2Kb 64.5Kb 20.9Kb server.example.com => ip.address 1.75Mb 3.08Mb 2.72Mb <= 16.6Kb 35.6Kb 32.5Kb server.example.com => ip.address 1.75Mb 2.90Mb 2.79Mb <= 22.4Kb 32.6Kb 35.6Kb server.example.com => ip.address 3.03Mb 2.78Mb 1.82Mb <= 26.6Kb 27.4Kb 20.2Kb server.example.com => ip.address 2.26Mb 2.66Mb 1.36Mb <= 51.7Kb 49.1Kb 24.4Kb server.example.com => ip.address 586Kb 2.50Mb 1.03Mb <= 4.17Kb 26.1Kb 10.7Kb server.example.com => ip.address 2.42Mb 2.49Mb 2.44Mb <= 31.6Kb 29.7Kb 29.9Kb server.example.com => ip.address 2.41Mb 2.46Mb 2.41Mb <= 26.4Kb 24.5Kb 23.8Kb server.example.com => ip.address 2.37Mb 2.39Mb 2.40Mb <= 28.9Kb 27.0Kb 28.5Kb server.example.com => ip.address 525Kb 2.20Mb 1.05Mb <= 7.03Kb 26.0Kb 12.8Kb qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq TX: cum: 102GB peak: 1.65Gb rates: 1.46Gb 1.44Gb 1.48Gb RX: 1.31GB 24.3Mb 19.5Mb 18.9Mb 20.0Mb TOTAL: 103GB 1.67Gb 1.48Gb 1.46Gb 1.50Gb I check the transfer speed using iperf utility From Server A to Server B # iperf -c 0.0.0.2 -p 8777 ------------------------------------------------------------ Client connecting to 0.0.0.2, TCP port 8777 TCP window size: 85.3 KByte (default) ------------------------------------------------------------ [ 3] local 0.0.0.1 port 38895 connected with 0.0.0.2 port 8777 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.8 sec 528 KBytes 399 Kbits/sec My Current Connections in Server B # netstat -an|grep ":8777"|awk '/tcp/ {print $6}'|sort -nr| uniq -c 2072 TIME_WAIT 28 SYN_RECV 1 LISTEN 189 LAST_ACK 139 FIN_WAIT2 373 FIN_WAIT1 3381 ESTABLISHED 34 CLOSING Server A Network Card Information Settings for eth0: Supported ports: [ TP ] Supported link modes: 100baseT/Full 1000baseT/Full 10000baseT/Full Supported pause frame use: No Supports auto-negotiation: Yes Advertised link modes: 10000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Speed: 10000Mb/s Duplex: Full Port: Twisted Pair PHYAD: 0 Transceiver: external Auto-negotiation: on MDI-X: Unknown Supports Wake-on: d Wake-on: d Current message level: 0x00000007 (7) drv probe link Link detected: yes Server B Network Card Information Settings for eth2: Supported ports: [ FIBRE ] Supported link modes: 10000baseT/Full Supported pause frame use: No Supports auto-negotiation: No Advertised link modes: 10000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: No Speed: 10000Mb/s Duplex: Full Port: Direct Attach Copper PHYAD: 0 Transceiver: external Auto-negotiation: off Supports Wake-on: d Wake-on: d Current message level: 0x00000007 (7) drv probe link Link detected: yes ifconfig server A eth0 Link encap:Ethernet HWaddr 00:25:90:ED:9E:AA inet addr:0.0.0.1 Bcast:0.0.0.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1202795665 errors:0 dropped:64334 overruns:0 frame:0 TX packets:2313161968 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:893413096188 (832.0 GiB) TX bytes:3360949570454 (3.0 TiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:2207544 errors:0 dropped:0 overruns:0 frame:0 TX packets:2207544 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:247769175 (236.2 MiB) TX bytes:247769175 (236.2 MiB) ifconfig Server B eth2 Link encap:Ethernet HWaddr 00:25:90:82:C4:FE inet addr:0.0.0.2 Bcast:0.0.0.2 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:39973046980 errors:0 dropped:1828387600 overruns:0 frame:0 TX packets:69618752480 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3013976063688 (2.7 TiB) TX bytes:102250230803933 (92.9 TiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:1049495 errors:0 dropped:0 overruns:0 frame:0 TX packets:1049495 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:129012422 (123.0 MiB) TX bytes:129012422 (123.0 MiB) Netstat -i on Server B # netstat -i Kernel Interface table Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg eth2 9000 0 42098629968 0 2131223717 0 73698797854 0 0 0 BMRU lo 65536 0 1077908 0 0 0 1077908 0 0 0 LRU I Turn up send/receive buffers on the network card to 2048 and problem still persist I increase the MTU for server A and problem still persist and i increase the MTU for server B for better connectivity and transfer speed but it couldn't transfer at all The problem is : as you can see from iperf utility, the transfer speed from server A to server B slow when i restart network service in server B the transfer in server A at full speed, after 2 minutes , it's getting slow How could i troubleshoot slow speed issue and fix it in server B ? Notice : if there any other commands i should execute in servers for more information, so it might help resolve the problem , let me know in comments

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  • C# slowdown while creating a bitmap - calculating distances from a large List of places for each pixel

    - by user576849
    I'm creating a graphic of the glow of lights above a geographic location based upon Walkers Law: Skyglow=0.01*Population*DistanceFromCenter^-2.5 I have a CSV file of places with 66,000 records using 5 fields (id,name,population,latitude,longitude), parsed on the FormLoad event and stored it in: List<string[]> placeDataList Then I set up nested loops to fill in a bitmap using SetPixel. For each pixel on the bitmap, which represents a coordinate on a map (latitude and longitude), the program loops through placeDataList – calculating the distance from that coordinate (pixel) to each place record. The distance (along with population) is used in a calculation to find how much cumulative sky glow is contributed to the coordinate from each place record. So, for every pixel, 66,000 distance calculations must be made. The problem is, this is predictably EXTREMELY slow – on the order of one line of pixels per 30 seconds or so on a 320 pixel wide image. This is unrelated to SetPixel, which I know is also slow, because the speed is similarly slow when adding the distance calculation results to an array. I don’t actually need to test all 66,000 records for every pixel, only the records within 150 miles (i.e. no skyglow is contributed to a coordinate from a small town 3000 miles away). But to find which records are within 150 miles of my coordinate I would still need to loop through all the records for each pixel. I can't use a smaller number of records because all 66,000 places contribute to skyglow for SOME coordinate in my map as it loops. This seems like a Catch-22, so I know there must be a better method out there. Like I mentioned, the slowdown is related to how many calculations I’m making per pixel, not anything to do with the bitmap. Any suggestions? private void fillPixels(int width) { Color pixelColor; int pixel_w = width; int pixel_h = (int)Math.Floor((width * 0.424088664)); Bitmap bmp = new Bitmap(pixel_w, pixel_h); for (int i = 0; i < pixel_h; i++) for (int j = 0; j < pixel_w; j++) { pixelColor = getPixelColor(i, j); bmp.SetPixel(j, i, pixelColor); } bmp.Save("Nightfall", System.Drawing.Imaging.ImageFormat.Jpeg); pictureBox1.Image = bmp; MessageBox.Show("Done"); } private Color getPixelColor(int height, int width) { int c; double glow,d,cityLat,cityLon,cityPop; double testLat, testLon; int size_h = (int)Math.Floor((size_w * 0.424088664)); ; testLat = (height * (24.443136 / size_h)) + 24.548874; testLon = (width * (57.636853 / size_w)) -124.640767; glow = 0; for (int i = 0; i < placeDataList.Count; i++) { cityPop=Convert.ToDouble(placeDataList[i][2]); cityLat=Convert.ToDouble(placeDataList[i][3]); cityLon=Convert.ToDouble(placeDataList[i][4]); d = distance(testLat, testLon, cityLat, cityLon,"M"); if(d<150) glow = glow+(0.01 * cityPop * Math.Pow(d, -2.5)); } if (glow >= 1) glow=1; c = (int)Math.Ceiling(glow * 255); return Color.FromArgb(c, c, c); }

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  • Performance Optimization &ndash; It Is Faster When You Can Measure It

    - by Alois Kraus
    Performance optimization in bigger systems is hard because the measured numbers can vary greatly depending on the measurement method of your choice. To measure execution timing of specific methods in your application you usually use Time Measurement Method Potential Pitfalls Stopwatch Most accurate method on recent processors. Internally it uses the RDTSC instruction. Since the counter is processor specific you can get greatly different values when your thread is scheduled to another core or the core goes into a power saving mode. But things do change luckily: Intel's Designer's vol3b, section 16.11.1 "16.11.1 Invariant TSC The time stamp counter in newer processors may support an enhancement, referred to as invariant TSC. Processor's support for invariant TSC is indicated by CPUID.80000007H:EDX[8]. The invariant TSC will run at a constant rate in all ACPI P-, C-. and T-states. This is the architectural behavior moving forward. On processors with invariant TSC support, the OS may use the TSC for wall clock timer services (instead of ACPI or HPET timers). TSC reads are much more efficient and do not incur the overhead associated with a ring transition or access to a platform resource." DateTime.Now Good but it has only a resolution of 16ms which can be not enough if you want more accuracy.   Reporting Method Potential Pitfalls Console.WriteLine Ok if not called too often. Debug.Print Are you really measuring performance with Debug Builds? Shame on you. Trace.WriteLine Better but you need to plug in some good output listener like a trace file. But be aware that the first time you call this method it will read your app.config and deserialize your system.diagnostics section which does also take time.   In general it is a good idea to use some tracing library which does measure the timing for you and you only need to decorate some methods with tracing so you can later verify if something has changed for the better or worse. In my previous article I did compare measuring performance with quantum mechanics. This analogy does work surprising well. When you measure a quantum system there is a lower limit how accurately you can measure something. The Heisenberg uncertainty relation does tell us that you cannot measure of a quantum system the impulse and location of a particle at the same time with infinite accuracy. For programmers the two variables are execution time and memory allocations. If you try to measure the timings of all methods in your application you will need to store them somewhere. The fastest storage space besides the CPU cache is the memory. But if your timing values do consume all available memory there is no memory left for the actual application to run. On the other hand if you try to record all memory allocations of your application you will also need to store the data somewhere. This will cost you memory and execution time. These constraints are always there and regardless how good the marketing of tool vendors for performance and memory profilers are: Any measurement will disturb the system in a non predictable way. Commercial tool vendors will tell you they do calculate this overhead and subtract it from the measured values to give you the most accurate values but in reality it is not entirely true. After falling into the trap to trust the profiler timings several times I have got into the habit to Measure with a profiler to get an idea where potential bottlenecks are. Measure again with tracing only the specific methods to check if this method is really worth optimizing. Optimize it Measure again. Be surprised that your optimization has made things worse. Think harder Implement something that really works. Measure again Finished! - Or look for the next bottleneck. Recently I have looked into issues with serialization performance. For serialization DataContractSerializer was used and I was not sure if XML is really the most optimal wire format. After looking around I have found protobuf-net which uses Googles Protocol Buffer format which is a compact binary serialization format. What is good for Google should be good for us. A small sample app to check out performance was a matter of minutes: using ProtoBuf; using System; using System.Diagnostics; using System.IO; using System.Reflection; using System.Runtime.Serialization; [DataContract, Serializable] class Data { [DataMember(Order=1)] public int IntValue { get; set; } [DataMember(Order = 2)] public string StringValue { get; set; } [DataMember(Order = 3)] public bool IsActivated { get; set; } [DataMember(Order = 4)] public BindingFlags Flags { get; set; } } class Program { static MemoryStream _Stream = new MemoryStream(); static MemoryStream Stream { get { _Stream.Position = 0; _Stream.SetLength(0); return _Stream; } } static void Main(string[] args) { DataContractSerializer ser = new DataContractSerializer(typeof(Data)); Data data = new Data { IntValue = 100, IsActivated = true, StringValue = "Hi this is a small string value to check if serialization does work as expected" }; var sw = Stopwatch.StartNew(); int Runs = 1000 * 1000; for (int i = 0; i < Runs; i++) { //ser.WriteObject(Stream, data); Serializer.Serialize<Data>(Stream, data); } sw.Stop(); Console.WriteLine("Did take {0:N0}ms for {1:N0} objects", sw.Elapsed.TotalMilliseconds, Runs); Console.ReadLine(); } } The results are indeed promising: Serializer Time in ms N objects protobuf-net   807 1000000 DataContract 4402 1000000 Nearly a factor 5 faster and a much more compact wire format. Lets use it! After switching over to protbuf-net the transfered wire data has dropped by a factor two (good) and the performance has worsened by nearly a factor two. How is that possible? We have measured it? Protobuf-net is much faster! As it turns out protobuf-net is faster but it has a cost: For the first time a type is de/serialized it does use some very smart code-gen which does not come for free. Lets try to measure this one by setting of our performance test app the Runs value not to one million but to 1. Serializer Time in ms N objects protobuf-net 85 1 DataContract 24 1 The code-gen overhead is significant and can take up to 200ms for more complex types. The break even point where the code-gen cost is amortized by its faster serialization performance is (assuming small objects) somewhere between 20.000-40.000 serialized objects. As it turned out my specific scenario involved about 100 types and 1000 serializations in total. That explains why the good old DataContractSerializer is not so easy to take out of business. The final approach I ended up was to reduce the number of types and to serialize primitive types via BinaryWriter directly which turned out to be a pretty good alternative. It sounded good until I measured again and found that my optimizations so far do not help much. After looking more deeper at the profiling data I did found that one of the 1000 calls did take 50% of the time. So how do I find out which call it was? Normal profilers do fail short at this discipline. A (totally undeserved) relatively unknown profiler is SpeedTrace which does unlike normal profilers create traces of your applications by instrumenting your IL code at runtime. This way you can look at the full call stack of the one slow serializer call to find out if this stack was something special. Unfortunately the call stack showed nothing special. But luckily I have my own tracing as well and I could see that the slow serializer call did happen during the serialization of a bool value. When you encounter after much analysis something unreasonable you cannot explain it then the chances are good that your thread was suspended by the garbage collector. If there is a problem with excessive GCs remains to be investigated but so far the serialization performance seems to be mostly ok.  When you do profile a complex system with many interconnected processes you can never be sure that the timings you just did measure are accurate at all. Some process might be hitting the disc slowing things down for all other processes for some seconds as well. There is a big difference between warm and cold startup. If you restart all processes you can basically forget the first run because of the OS disc cache, JIT and GCs make the measured timings very flexible. When you are in need of a random number generator you should measure cold startup times of a sufficiently complex system. After the first run you can try again getting different and much lower numbers. Now try again at least two times to get some feeling how stable the numbers are. Oh and try to do the same thing the next day. It might be that the bottleneck you found yesterday is gone today. Thanks to GC and other random stuff it can become pretty hard to find stuff worth optimizing if no big bottlenecks except bloatloads of code are left anymore. When I have found a spot worth optimizing I do make the code changes and do measure again to check if something has changed. If it has got slower and I am certain that my change should have made it faster I can blame the GC again. The thing is that if you optimize stuff and you allocate less objects the GC times will shift to some other location. If you are unlucky it will make your faster working code slower because you see now GCs at times where none were before. This is where the stuff does get really tricky. A safe escape hatch is to create a repro of the slow code in an isolated application so you can change things fast in a reliable manner. Then the normal profilers do also start working again. As Vance Morrison does point out it is much more complex to profile a system against the wall clock compared to optimize for CPU time. The reason is that for wall clock time analysis you need to understand how your system does work and which threads (if you have not one but perhaps 20) are causing a visible delay to the end user and which threads can wait a long time without affecting the user experience at all. Next time: Commercial profiler shootout.

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  • Uncovering Compiler Errors in ASP.NET MVC Views

    - by Ben Griswold
    ASPX and ASCX files are compiled on the fly when they are requested on the web server. This means it’s possible that you aren’t catching compile errors associated with your views when you build your ASP.NET MVC project in Visual Studio.  Unless you’re willing to click through your entire application, rendering each view looking for errors, you application is left a little vulnerable to user issues.  Fortunately, there’s a work around.  Open up your MVC project file in notepad or within the Visual Studio IDE by unloading the project and then editing the .csproj file (both actions are available by right-clicking on the Project Node in Solution Explorer.)  Notice the MvcBuildViews option.  It’s probably set to false.  Flip the value to true and you’ll magically start compiling your views when you build your application. <MvcBuildViews>false</MvcBuildViews> Taking this action will slow down your builds a bit, but if you’re a hack like me, it’ll probably save your day in the long run. Now you’re probably thinking, “Neat trick – how’s it work?”  Scroll down toward the bottom of your csproj file and you will notice the AfterBuild target triggers the AspNetCompiler action if the MvcBuildViews option is set to true.  <Target Name="AfterBuild" Condition="'$(MvcBuildViews)'=='true'">   <AspNetCompiler VirtualPath="temp"                   PhysicalPath="$(ProjectDir)\..\$(ProjectName)" /> </Target> Great. One more thing. Let’s say you don’t want to slow down all of your builds, but you absolutely want to know if there are any compiler issues with your views before you commit your code to version control or deploy or whatever.  Here’s what you can do – change the AfterBuild condition to run if your configuration is set to Release mode.  <Target Name="AfterBuild" Condition="'$(Configuration)'=='Release'">   <!– Always pre-compile ASPX and ASCX in release mode –>   <AspNetCompiler VirtualPath="temp"                   PhysicalPath="$(ProjectDir)\..\$(ProjectName)" /> </Target> Now your debug mode builds will continue to be as fast as ever and you can quickly validate your views by building in release mode when you so choose.  There’s one little catch – this setup won’t consider the MvcBuildViews option whatsoever! So if you decide to go with this configuration, you might want to add a comment near the MvcBuildViews option letting other developers know they can change the MvcBuildViews option as much as they’d like but it’s not going to affect the AfterBuild action.  Or don’t include the comment and let your team members figure it out for themselves…

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  • SQL SERVER – How to Ignore Columnstore Index Usage in Query

    - by pinaldave
    Earlier I wrote about SQL SERVER – Fundamentals of Columnstore Index and very first question I received in email was as following. “We are using SQL Server 2012 CTP3 and so far so good. In our data warehouse solution we have created 1 non-clustered columnstore index on our large fact table. We have very unique situation but your article did not cover it. We are running few queries on our fact table which is working very efficiently but there is one query which earlier was running very fine but after creating this non-clustered columnstore index this query is running very slow. We dropped the columnstore index and suddenly this one query is running fast but other queries which were benefited by this columnstore index it is running slow. Any workaround in this situation?” In summary the question in simple words “How can we ignore using columnstore index in selective queries?” Very interesting question – you can use I can understand there may be the cases when columnstore index is not ideal and needs to be ignored the same. You can use the query hint IGNORE_NONCLUSTERED_COLUMNSTORE_INDEX to ignore the columnstore index. SQL Server Engine will use any other index which is best after ignoring the columnstore index. Here is the quick script to prove the same. We will first create sample database and then create columnstore index on the same. Once columnstore index is created we will write simple query. This query will use columnstore index. We will then show the usage of the query hint. USE AdventureWorks GO -- Create New Table CREATE TABLE [dbo].[MySalesOrderDetail]( [SalesOrderID] [int] NOT NULL, [SalesOrderDetailID] [int] NOT NULL, [CarrierTrackingNumber] [nvarchar](25) NULL, [OrderQty] [smallint] NOT NULL, [ProductID] [int] NOT NULL, [SpecialOfferID] [int] NOT NULL, [UnitPrice] [money] NOT NULL, [UnitPriceDiscount] [money] NOT NULL, [LineTotal] [numeric](38, 6) NOT NULL, [rowguid] [uniqueidentifier] NOT NULL, [ModifiedDate] [datetime] NOT NULL ) ON [PRIMARY] GO -- Create clustered index CREATE CLUSTERED INDEX [CL_MySalesOrderDetail] ON [dbo].[MySalesOrderDetail] ( [SalesOrderDetailID]) GO -- Create Sample Data Table -- WARNING: This Query may run upto 2-10 minutes based on your systems resources INSERT INTO [dbo].[MySalesOrderDetail] SELECT S1.* FROM Sales.SalesOrderDetail S1 GO 100 -- Create ColumnStore Index CREATE NONCLUSTERED COLUMNSTORE INDEX [IX_MySalesOrderDetail_ColumnStore] ON [MySalesOrderDetail] (UnitPrice, OrderQty, ProductID) GO Now we have created columnstore index so if we run following query it will use for sure the same index. -- Select Table with regular Index SELECT ProductID, SUM(UnitPrice) SumUnitPrice, AVG(UnitPrice) AvgUnitPrice, SUM(OrderQty) SumOrderQty, AVG(OrderQty) AvgOrderQty FROM [dbo].[MySalesOrderDetail] GROUP BY ProductID ORDER BY ProductID GO We can specify Query Hint IGNORE_NONCLUSTERED_COLUMNSTORE_INDEX as described in following query and it will not use columnstore index. -- Select Table with regular Index SELECT ProductID, SUM(UnitPrice) SumUnitPrice, AVG(UnitPrice) AvgUnitPrice, SUM(OrderQty) SumOrderQty, AVG(OrderQty) AvgOrderQty FROM [dbo].[MySalesOrderDetail] GROUP BY ProductID ORDER BY ProductID OPTION (IGNORE_NONCLUSTERED_COLUMNSTORE_INDEX) GO Let us clean up the database. -- Cleanup DROP INDEX [IX_MySalesOrderDetail_ColumnStore] ON [dbo].[MySalesOrderDetail] GO TRUNCATE TABLE dbo.MySalesOrderDetail GO DROP TABLE dbo.MySalesOrderDetail GO Again, make sure that you use hint sparingly and understanding the proper implication of the same. Make sure that you test it with and without hint and select the best option after review of your administrator. Here is the question for you – have you started to use SQL Server 2012 for your validation and development (not on production)? It will be interesting to know the answer. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – BACKUPIO, BACKUPBUFFER – Wait Type – Day 14 of 28

    - by pinaldave
    Backup is the most important task for any database admin. Your data is at risk if you are not performing database backup. Honestly, I have seen many DBAs who know how to take backups but do not know how to restore it. (Sigh!) In this blog post we are going to discuss about one of my real experiences with one of my clients – BACKUPIO. When I started to deal with it, I really had no idea how to fix the issue. However, after fixing it at two places, I think I know why this is happening but at the same time, I am not sure the fix is the best solution. The reality is that the fix is not a solution but a workaround (which is not optimal, but get your things done). From Book On-Line: BACKUPIO Occurs when a backup task is waiting for data, or is waiting for a buffer in which to store data. This type is not typical, except when a task is waiting for a tape mount. BACKUPBUFFER Occurs when a backup task is waiting for data, or is waiting for a buffer in which to store data. This type is not typical, except when a task is waiting for a tape mount. BACKUPIO and BACKUPBUFFER Explanation: This wait stats will occur when you are taking the backup on the tape or any other extremely slow backup system. Reducing BACKUPIO and BACKUPBUFFER wait: In my recent consultancy, backup on tape was very slow probably because the tape system was very old. During the time when I explained this wait type reason in the consultancy, the owners immediately decided to replace the tape drive with an alternate system. They had a small SAN enclosure not being used on side, which they decided to re-purpose. After a week, I had received an email from their DBA, saying that the wait stats have reduced drastically. At another location, my client was using a third party tool (please don’t ask me the name of the tool) to take backup. This tool was compressing the backup along with taking backup. I have had a very good experience with this tool almost all the time except this one sparse experience. When I tried to take backup using the native SQL Server compressed backup, there was a very small value on this wait type and the backup was much faster. However, when I attempted with the third party backup tool, this value was very high again and was taking much more time. The third party tool had many other features but the client was not using these features. We end up using the native SQL Server Compressed backup and it worked very well. If I get to see this higher in my future consultancy, I will try to understand this wait type much more in detail and so probably I would able to come to some solid solution. Read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • SQL Authority News – FalafelCON 2014: 2 days with the Best Developers in the World

    - by Pinal Dave
    I love presenting at various forums on various technologies. I am extremely excited that I got invited to speak at Falafel Conference 2014 in San Francisco. I will present two technology sessions on SQL Server. If you are into web development or if you just want to attend a conference with the best of the industry speakers, this may be the right conference for you. What set apart this conference from other conference is technology presented as well as speakers. Usually one has to attend very expensive and high scale event when they have to hear good speakers. At this conference, you will find quite a many industry legends are available to present on the bleeding edge technology. Here are few of the reasons why I believe you should attend this conference: Choose from four tracks covering Web, Mobile development and testing, Sitefinity, and Automated Testing, or attend sessions from all four! Learn from the best developers and testers in the business in an intimate setting. Surround yourself with your peers and the opportunity to network Learn about the latest platforms and technologies including Kendo UI, AngularJS, ASP.NET MVC, WebAPI, and more! Here are the details for the sessions which I am going to present at Falafel Conference. Secrets of SQL Server: Database Worst Practices Abstract: Chances are you have heard, or even uttered, this expression. This demo-oriented session will show many examples where database professionals were dumbfounded by their own mistakes, and could even bring back memories of your own early DBA days. The goal of this session is to expose the small details that can be dangerous to the production environment and SQL Server as a whole, as well as talk about worst practices and how to avoid them. Shedding light on some of these perils and the tricks to avoid them may even save your current job. After attending this session, Developers will only need 60 seconds to improve performance of their database server in their SharePoint implementation. We will have a quiz during the session to keep the conversation alive. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Additionally, all attendees of the session will have access to learning material presented in the session. The Unsung Hero Abstract: Slow Running Queries are the most common problem that developers face while working with SQL Server. While it is easy to blame the SQL Server for unsatisfactory performance, however the issue often persists with the way queries have been written, and how Indexes has been set up. The session will focus on the ways of identifying problems that slow down SQL Server, and Indexing tricks to fix them. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Register Now! I have learned from the Falafel Team that they are running out of tickets and soon they will close the registration.  For next 10 days the price for the registration is only USD 149. Trust me, you can’t get such a world class training and networking opportunity at such a low price. Click to Register Here! Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL

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  • On a BPM Mission with Process Accelerators. Part 1: BPM as an ATV

    - by Cesare Rotundo
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Part 1: BPM as an ATV It’s always exciting to talk to customers that are in the middle of a BPM transformational journey. Their thirst for new processes to improve with BPM makes them explorers in a landscape of opportunities. They have discovered that with BPM the can “go places” they couldn’t reach before. In a way, learning how to generate value with BPM is like adopting a new mean of transportation. Apps are like regular cars: very efficient, but to be used on paved roads: the road/process has been traced, and there are fixed paths to follow to get from “opportunity to quote” or from “quote to cash”. Getting off the road is risky, and laying down new asphalt is slow and expensive. Custom development is like running: you can go virtually anywhere, following any path you like, yet it’s slow, and a lot of sweat. BPM allows you to go “off the beaten path” laid out by packaged apps, yet make fast progress compared to custom development. BPM is therefore more like an All-Terrain Vehicle (ATV): less efficient than a car, but much faster than running, with a powerful enough engine that can get you places. The similarities between BPM and ATVs don’t stop here: you must learn to ride it even if you already know how to drive a car; you can reach places but figuring out the path to your destination is harder. Ultimately, with BPM as with an ATV, you reach places that you thought you could never reach, and you discover new destinations that provide great benefit to you … and that you didn’t even know existed! That’s where the sense of accomplishment that we heard from our BPM customers comes from, as well as the desire to share their experience, or even, as in the case of a County, the willingness to contribute their BPM solutions to help other agencies that face the same challenges. The question we wanted to answer is how can we teach organizations to drive ATV/BPM, thus leading them to deeper success with BPM, while increasing their awareness of the potential for reaching new targets, and finally equip them with the right tools. Like with ATVs, getting from point A to point B is more of a work of art than cruising on the highway by car. There is a lot we can do: after all many sought after destinations are common: someone else has been on the same path before. If only you could learn from their experience …

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  • Rethinking Oracle Optimizer Statistics for P6 Part 2

    - by Brian Diehl
    In the previous post (Part 1), I tried to draw some key insights about the relationship between P6 and Oracle Optimizer Statistics.  The first is that average cardinality has the greatest impact on query optimization and that the particular queries generated by P6 are more likely to use this average during calculations. The second is that these are statistics that are unlikely to change greatly over the life of the application. Ultimately, our goal is to get the best query optimization possible.  Or is it? Stability No application administrator wants to get the call at 9am that their application users cannot get there work done because everything is running slow. This is a possibility with a regularly scheduled nightly collection of statistics. It may not just be slow performance, but a complete loss of service because one or more queries are optimized poorly. Ideally, this should not be the case. The database optimizer should make better decisions with more up-to-date data. Better statistics may give incremental performance benefit. However, this benefit must be balanced against the potential cost of system down time.  It is stability that we ultimately desire and not absolute optimal performance. We do want the benefit from more accurate statistics and better query plans, but not at the risk of an unusable system. As a result, I've developed the following methodology around managing database statistics for the P6 database.  1. No Automatic Re-Gathering - The daily, weekly, or other interval of statistic gathering is unlikely to be beneficial. Quite the opposite. It is more likely to cause problems. 2. Smart Re-Gathering - The time to collect statistics is when things have changed significantly. For a new installation of P6, this is happening more often because the data is growing from a few rows to thousands and more. But for a mature system, the data is not changing significantly from week-to-week. There are times to collect statistics: New releases of the application Changes in the underlying hardware or software versions (ex. new Oracle RDBMS version) When additional user groups are added. The new groups may use the software in significantly different ways. After significant changes in the data. This may be monthly, quarterly or yearly.  3. Always Test - If you take away one thing from this post, it would be to always have a plan to test after changing statistics. In reality, statistics can be collected as often as you desire provided there are tests in place to verify that performance is the same or better. These might be automated tests or simply a manual script of application functions. 4. Have a Way Out - Never change the statistics without a way to return to the previous set. Think of the statistics as one part of the overall application code that also includes the source code--both application and RDBMS. It would be foolish to change to the new code without a way to get back to the previous version. In the final post, I will talk about the actual script I created for P6 PMDB and possible future direction for managing query performance. 

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  • jQuery dropdown is really jumpy

    - by Matthew Westrik
    Hi, I'm making a dropdown menu with jquery (some of the code is borrowed from a tutorial by someone, although I forget who...). When I use the dropdown, it slides up and down really fast, and I can't figure it out. What do you think? HTML <div id="nav"> <ul class="topnav"> <li><a class="selected" href="#" title="home">home</a></li> <li><a href="events/" title="events calendar">events</a></li> <li><a href="photos/" title="photo gallery">photos</a></li> <li><a href="staff/" title="faculty">staff</a> <ul class="subnav"> <li><a href="#">Luke</a></li> <li><a href="#">Darth Vader</a></li> <li><a href="#">Princess Leia</a></li> <li><a href="#">Jabba the Hutt</a></li> </ul> </li> <li><a href="contact/" title="contact">contact</a></li> jQuery $(document).ready(function(){ $("ul.subnav").parent() .hover(function() { $(this).parent().find("ul.subnav").slideDown('fast').show(); //Drop down the subnav on hover... $(this).parent() .hover(function() { }, function(){ $(this).parent().find("ul.subnav").slideUp('slow'); }); $(this).parent().find("ul.subnav") .hover(function() { }, function(){ $(this).parent().find("ul.subnav").slideUp('slow'); }); }).hover(function() { $(this).addClass("subhover"); }, function(){ $(this).removeClass("subhover"); });

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  • Get ListView Visible items

    - by Vincent Piel
    I have a ListView which might contains a lot of items, so it is virtualized and recycling items. It does not use sort. I need to refresh some value display, but when there are too many items, it is too slow to update everything, so I would like to refresh only the visible items. How could I get a list of all currently displayed items ? I tried to look into the ListView or in the ScrollViewer, but I still have no idea how to achieve this. The solution must NOT go through all items to test if they can be seen, because this would be too slow. I'm not sure code or xaml would be usefull, it is just a Virtualized/Recycling ListView with its ItemSource bound to an Array. Edit Answer : thanks to akjoshi, i found the way : get the ScrollViewer of the ListView (with a FindDescendant method, that you can do yourself with the VisualTreeHelper ). Then use its ScrollViewer.VerticalOffset : it is the number of the first item shown and ScrollViewer.ViewportHeight : it is the count of items shown. Rq : CanContentScroll must be true.

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  • Fastest way to remove non-numeric characters from a VARCHAR in SQL Server

    - by Dan Herbert
    I'm writing an import utility that is using phone numbers as a unique key within the import. I need to check that the phone number does not already exist in my DB. The problem is that phone numbers in the DB could have things like dashes and parenthesis and possibly other things. I wrote a function to remove these things, the problem is that it is slow and with thousands of records in my DB and thousands of records to import at once, this process can be unacceptably slow. I've already made the phone number column an index. I tried using the script from this post: http://stackoverflow.com/questions/52315/t-sql-trim-nbsp-and-other-non-alphanumeric-characters But that didn't speed it up any. Is there a faster way to remove non-numeric characters? Something that can perform well when 10,000 to 100,000 records have to be compared. Whatever is done needs to perform fast. Update Given what people responded with, I think I'm going to have to clean the fields before I run the import utility. To answer the question of what I'm writing the import utility in, it is a C# app. I'm comparing BIGINT to BIGINT now, with no need to alter DB data and I'm still taking a performance hit with a very small set of data (about 2000 records). Could comparing BIGINT to BIGINT be slowing things down? I've optimized the code side of my app as much as I can (removed regexes, removed unneccessary DB calls). Although I can't isolate SQL as the source of the problem anymore, I still feel like it is.

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  • jQuery UI - addClass removeClass - CSS values are stuck

    - by Jason D
    Hi, I'm trying to do a simple animation. You show the div. It animates correctly. You hide the div. Correct. You show the div again. It shows but there is no animation. It is stuck at the value of when you first interrupted it. So somehow the interpolation CSS that is happening during [add|remove]Class is getting stuck there. The second time around, the [add|remove]Class is actually running, but the css it's setting from the class is getting ignored (I think being overshadowed). How can I fix this WITHOUT resorting to .animate and hard-coded style values? The whole point was to put the animation end point in a css class. Thanks! <!doctype html> <style type="text/css"> div { width: 400px; height: 200px; } .green { background-color: green; } </style> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" type="text/javascript"></script> <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js" type="text/javascript"></script> <script type="text/javascript"> $(function() { $('#show').bind({ click: function() { showAndRun() } }) $('#hide').bind({ click: function() { $('div').stop(true, false).fadeOut('slow') } }) function showAndRun() { function pulse() { $('div').removeClass('green', 2000, function() { $(this).addClass('green', 2000, pulse) }) } $('div').stop(true, false).hide().addClass('green').fadeIn('slow', pulse) } }) </script> <input id="show" type="button" value="show" /><input id="hide" type="button" value="hide" /> <div style="display: none;"></div>

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  • Increment variable for

    - by John Doe
    Hello. I have 30 divs with the same class on the same page. When i'm pressing the title (.pull) the content is sliding up (.toggle_container). When the content is hidden and i'm pressing the title again, the content is sliding down. Also, i want to store the div state inside a cookie. I modified my original code to store the div state inside a cookie but it's not working for all the divs (pull1, toggle_container1, pull2, toggle_container2 [...]), it's working only for the first one (pull0, toggle_container0). What i'm doing wrong? var increment = 0; if ($.cookie('showTop') == 'collapsed') { $(".toggle_container" + increment).hide(); }else { $(".toggle_container" + increment).show(); }; $("a.pull" + increment).click(function () { if ($(".toggle_container" + increment).is(":hidden")) { $(".toggle_container" + increment).slideDown("slow"); $.cookie('showTop', 'expanded'); increment++; } else { $(".toggle_container" + increment).slideUp("slow"); $.cookie('showTop', 'collapsed'); increment++; } return false; });

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  • Python: speed up removal of every n-th element from list.

    - by ChristopheD
    I'm trying to solve this programming riddle and althought the solution (see code below) works correct, it is too slow for succesful submission. Any pointers as how to make this run faster? (removal of every n-th element from a list)? Or suggestions for a better algorithm to calculate the same; seems I can't think of anything else then brute-force for now... Basically the task at hand is: GIVEN: L = [2,3,4,5,6,7,8,9,10,11,........] 1. Take the first remaining item in list L (in the general case 'n'). Move it to the 'lucky number list'. Then drop every 'n-th' item from the list. 2. Repeat 1 TASK: Calculate the n-th number from the 'lucky number list' ( 1 <= n <= 3000) My current code (it calculates the 3000 first lucky numbers in about a second on my machine - but unfortunately too slow): """ SPOJ Problem Set (classical) 1798. Assistance Required URL: http://www.spoj.pl/problems/ASSIST/ """ sieve = range(3, 33900, 2) luckynumbers = [2] while True: wanted_n = input() if wanted_n == 0: break while len(luckynumbers) < wanted_n: item = sieve[0] luckynumbers.append(item) items_to_delete = set(sieve[::item]) sieve = filter(lambda x: x not in items_to_delete, sieve) print luckynumbers[wanted_n-1]

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