…isn’t really deleted. The MySQL server keeps an open filehandle to the file, and …of connections all trying to open or close tables can indicate LOCK_open contention. Replication is delayed… allocating too much memory. A runaway server process, or poorly optimized queries, can consume too much memory …
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
…tables in MySQL 5.1 Disk Space For MyISAM tables hosting providers used to use disk quotas for MyISAM tables….as temporary tables, so by opening large amount of cursors which are handled as in-memory temporary tables you…some global quotas so it can’t consume too much memory and also you can’t get all…
Post: What to tune in MySQL Server after installation
September 29, 2006 By 116 Comments
…_mem_pool_size This one does not really affect performance too much, at least on OS with decent memory allocators. Still you… case MySQL Server crashes. Value 2 only cause data loss with full OS crash. table_cache – Opening tables can be expensive. For example MyISAM tables mark MYI header to mark table as currently in use…
Post: How to debug long-running transactions in MySQL
March 8, 2011 By 6 Comments
… transaction. If a transaction remains open for a very long time … be fixed. I see this much too often, and have developed a… INFORMATION_SCHEMA tables that make this simple. Just query the tables, and …port} > /root/tcpdumps/`date +%s`-tcpdump & mysql -e ‘show innodb status\Gshow full processlist’ >…
Post: Using VIEW to reduce number of tables used
September 28, 2007 By 12 Comments
…require at least 16K page in Innodb), keeping all tables open in Innodb dictionary and number of other challenges … users per table it is best way to go, however quite typically this is way too much work and … do not pass user_id value to underlying table MySQL tries to set it to default, which does …
Post: Wanted: Better memory profiling for MySQL
May 18, 2008 By 4 Comments
… frequently I would log in to customers system and find MySQL using too much memory. I would look at memory consumed by Innodb… to operation system ? Could it be some buffers associated with opened tables, prepared statements etc ? Could it be some of the queries… ? It also could be memory leak in MySQL or runaway stored procedure consuming too much memory, but there is no way to see…
Post: Top 5 Wishes for MySQL
June 29, 2007 By 10 Comments
…MySQL Scaling to large amount of CPUs for all storage engines all operation systems and all workloads. Well this may be too much… summary tables and other tricks we use when such need arises but we still can’t deny – MySQL… is only fixed in MySQL 5.1 and Most of other items are still open. Well may be…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
… to try micro instances.*EDIT* The storage worker currently logs too much information. This can cause the disk to fill up with… table-definition-cache=16384 table-open-cache=128 thread-cache-size=32 thread-stack=256K tmp-table-size=64M transaction-isolation=READ-COMMITTED user=mysql…
Post: MySQL File System Fragmentation Benchmarks
March 21, 2008 By 28 Comments
…tables and does specified number of inserts going to random tables. I used default MySQL settings for MyISAM (table… index header (most complex part of opening and closing MyISAM table) can happen by OS in … large tables. For 10000 tables we had just 1000 of 4K rows in the table which caused too much …
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…give much greater …, too….tables, I’ll paste in mysql> show global variables like ‘%table_size%’; +———————+———–+ | Variable_name | Value | +———————+———–+ | max_heap_table_size | 268435456 | | tmp_table…openings in chess — the great chess players study openings…
