… sleep 60 done Check for Table Cache Related Allocations There are cases when MySQL will allocate a lot of memory for table cache, especially… Tables MEMORY tables can take memory. There are implicit MEMORY tables which are allocated for query execution, which size can be controlled by tmp_table_size…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
… in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a… optimizer enhancement Index Condition Pushdown (ICP). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take…
Post: InnoDB's gap locks
March 27, 2012 By 14 Comments
…struct(s), heap size 1248, 3 row lock(s), undo log entries 1 MySQL thread id 3, OS thread handle 0x7f84a78ba700, query id 163 localhost msandbox TABLE LOCK table `… locks except for foreign-key constraint checking or duplicate-key checking. The most important difference between…
Comment: Too many connections? No problem!
March 15, 2012 By 28 Comments
…_cache_size=32M thread_cache_size=30 table_cache=4096 join_buffer_size=6M key_buffer_size=12M server-id = 1 log-bin=/data/mysql/drbd expire_logs_days = 5 max_binlog_size = 100M [client] socket=/data/mysql/mysql.sock… and I have to re-restart the server. I’ve checked the security aspect and not an attack, will have any…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want…_zoneblogpercona.commanual table_definition_cacheblogpercona.commanual table_lock_wait_timeoutblogpercona.commanual Table_locks_immediateblogpercona.commanual Table_locks_waitedblogpercona.commanual table_open_cacheblogpercona.commanual table_typeblogpercona.commanual…
Post: How to Monitor MySQL with Percona's Nagios Plugins
February 22, 2012 By 8 Comments
…The pmp-check-mysql-replication-delay plugin checks for excessive delay, and pmp-check-mysql-replication-running checks …table-checksum tool from Percona Toolkit can generate table checksums, and the pmp-check-pt-table…connections problems (the use of fixed-size connection pooling, for example, which …
Post: Make your file system error resilient
August 24, 2011 By 8 Comments
… blocks: 3616208434 Free inodes: 226918374 First block: 0 Block size: 4096 Fragment size: 4096 Reserved GDT blocks: 316 Blocks per group: 32768… auto check functions for your data partition and just check it manually as needed, same as you would every so often check MySQL tables for corruption. To change those options you can run tune2fs -m0 -i0 -c -1 /dev/sda1 changing reserved block percent, check…
Post: Can we improve MySQL variable handling ?
February 18, 2012 By 8 Comments
… detect such change easily because MySQL Server does not seems to have an easy way to check what was the default value…-mutexes FALSE tmp-table-size 16777216 tmpdir /tmp transaction-alloc-block-size 8192 transaction-isolation REPEATABLE-READ transaction-prealloc-size 4096 updatable-views-with…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…tables and Created_disk_tmp_tables, I’ll paste in mysql> show global variables like ‘%table_size%’; +———————+———–+ | Variable_name | Value | +———————+———–+ | max_heap_table_size | 268435456 | | tmp_table_size… checking for default users in the mysql.* tables…
Post: Aligning IO on a hard disk RAID – the Theory
June 9, 2011 By 15 Comments
… Server you can now customize page size and it may be good idea to check that page size is no bigger than stripe…) Disk /dev/sda: 2339840000s Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 2048s… be using an offset, what stripe size and how many stripe elements. It’s easy to check if you’re aligned – run…
