… tend not to think too much about is…MySQL replication from this instance, since MySQL replication is asynchronous. What about semi-sync MySQL…. This really will open a large window…table with a statement like this: UPDATE achievements SET count = count + 1 where achievement = ‘killed_troll’; How many…
Post: How to Monitor MySQL with Percona's Nagios Plugins
February 22, 2012 By 11 Comments
… a snapshot is failed or overly full. Too many deadlocks. Deadlocks (and lock wait timeouts, covered …file isn’t really deleted. The MySQL server keeps an open filehandle to the file, and it…up of connections all trying to open or close tables can indicate LOCK_open contention. Replication is delayed …
Post: How innodb_open_files affects performance
November 18, 2009 By 4 Comments
… keep open file descriptor when table is open – open table is purely logical state and appropriate .ibd file may be open or closed. Furthermore besides MySQL table_cache…_open in InnoDB: my.cnf. InnoDB: fil_sys open file LRU len 0 091118 18:47:44 InnoDB: Warning: too many (68) files stay open…
Comment: table_cache negative scalability
April 14, 2010 By 23 Comments
… [ERROR] Error in accept: Too many open files 100414 0:21:52 [ERROR] /usr/local/mysql/bin/mysqld: Can’t open file: ‘./wc_miehr_posasmp…’t open file: ‘./wc_miehr_posasmp/panel_decert.frm’ (errno: 24) [root@wcdb /db]# perror 24 OS error code 24: Too many open files I have this many MyISAM tables: [root@xxx /db/mydata]# find -L . -name…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
…Tables You can build query (with derived tables) which uses as many temporary tables…tables in MySQL 5.1 Disk Space For MyISAM tables hosting providers used to use disk quotas for MyISAM tables… are too old …tables, so by opening large amount of cursors which are handled as in-memory temporary tables…
Post: MySQL 5.5 and MySQL 5.6 default variable values differences
February 21, 2013 By 8 Comments
…MySQL 5.5.30 and MySQL 5.6.10 to the different tables and ran the query: mysql […I do not expect large impact here. table_open_cache is increased from 400 to …default as value of 1M is too small to be practical if someone…number of tables or if you do many create/drop of innodb tables. optimizer_switch…
Post: What to tune in MySQL Server after installation
September 29, 2006 By 118 Comments
…does not really affect performance too much, at least on OS …MySQL Server crashes. Value 2 only cause data loss with full OS crash. table_cache – Opening tables can be expensive. For example MyISAM tables…tables (remember each connection needs its own entry) if you have many connections or many tables…
Comment: table_cache negative scalability
April 14, 2010 By 23 Comments
… [ERROR] Error in accept: Too many open files 100414 0:21:52 [ERROR] /usr/local/mysql/bin/mysqld: Can’t open file: ‘./wc_miehr_posasmp… MyISAM and InnoDB table cache? 3) Would converting the MyISAM tables to InnoDB fix or help the os ulimit max open tables issue? Thanks for your help! Server info: Server version: 5.0.79-enterprise-log MySQL Enterprise Server (Commercial…
Post: How to debug long-running transactions in MySQL
March 8, 2011 By 6 Comments
…many things that can cause a “server stall” is a long-running transaction. If a transaction remains open… I see this much too often, and have …_SCHEMA tables that make this simple. Just query the tables, …> /root/tcpdumps/`date +%s`-tcpdump & mysql -e ‘show innodb status\Gshow full processlist’…
Post: State of MySQL Market and will Replication live ?
April 9, 2008 By 29 Comments
… for many web properties – too complex and too expensive to start with. In second half of 90s when MySQL appeared on the market many web… enjoy running too many servers. For others it becomes space and power constraint. It is also worth to mention Web vs Open Source… and Scalability on the scale of Big Table with Map Reduce. Indeed I think MySQL Replication usage will reduce, but I would…
