….28 and newer: pt-table-chcecksum pt-online-schema-change pt-archive pt-mysql-summary pt-heartbeat pt-variable-advisor pt-config…. Now pt-heartbeat uses UTC regardless of the server or MySQL time zone. Fixed bug 1079341: pt-online-schema-change checks for foreign keys on MyISAM tables. Since MyISAM tables can’t have foreign keys, and the tool uses the information_schema…
Post: Percona Toolkit 2.1.8 released today with beta support for MySQL 5.6
January 9, 2013 By Leave a Comment
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 64 Comments
…, at least we can use same “cheat” as MySQL 5.5 uses for Innodb Buffer Pool and have multiple MySQL Query Cache instances hashed… ? Right now none of such information is available which makes it hard to understand how exactly MySQL Query Cache is working in… Cache content and operation can be presented as some INFORMATION_SCHEMA tables. Self Refresh MySQL Query Cache causes not uniform performance as you…
Comment: Finding out largest tables on MySQL Server
February 4, 2008 By 27 Comments
Unomi, you need to use information_schema: mysql> use information_schema;
Post: Using innodb_sys_tables and innodb_sys_indexes
June 15, 2012 By Leave a Comment
…very hard to catch this problem without additional information_schema tables we added in Percona Server. I was…it is not the case: mysql> select * from innodb_sys_tables; +———-+——–+——————+——+——–+——-+ | TABLE_ID | SCHEMA | NAME | FLAG | N_COLS | SPACE | …
Post: MySQL opening .frm even when table is in table definition cache
November 21, 2011 By 8 Comments
… INFORMATION_SCHEMA tables (I think it is actually the TABLES table, but didn’t look closely) An example of how this is used is that in the DROP TABLE code path, MySQL uses this magic byte to work out… of this bit of code is that MySQL may cause unnecessary disk IO for information it already has cached (often at least…
Post: Can we improve MySQL variable handling ?
February 18, 2012 By 8 Comments
… default option was used and we change it in run time we can’t detect such change easily because MySQL Server does…) mysql> select @@global.sort_buffer_size; +—————————+ | @@global.sort_buffer_size | +—————————+ | 2097152 | +—————————+ 1 row in set (0.00 sec) This could be used… dealing with MySQL variables in automated way a lot more convenient would be extending INFORMATION_SCHEMA.GLOBAL_VARIABLES Currently as of MySQL 5.5…
Post: Innodb vs MySQL index counts
November 29, 2011 By 6 Comments
… different from the number of indexes 7 defined in the MySQL This customer was running Percona Server 5.1 and they… to simply use the INFORMATION_SCHEMA.INNODB_SYS_INDEXES table, which exists in Percona Server 5.1, but doesn’t appear in MySQL until… consider this on a newer version of Percona Server or MysqL 5.6. Another person (I’m looking at you, Baron…
Post: Quickly finding unused indexes (and estimating their size)
December 5, 2012 By 2 Comments
… snapshot of it into our schema with one command: mysql> create table index_analysis.used_indexes select * from information_schema.index_statistics; If the stats…_total_size from information_schema.tables t join information_schema.statistics i using (table_schema, table_name) join information_schema.innodb_index_stats s using (table_schema, table_name, index…
Post: Using Multiple Key Caches for MyISAM Scalability
November 26, 2008 By 8 Comments
… static) To get accurate information about table usage I will use Percona Patches: mysql> select * from information_schema.table_statistics where table_schema=’test’ and table… table sizes we can use traditional TABLES table: mysql> select table_schema,table_name,index_length from information_schema.tables where table_schema=’test’ and table…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
….D_DateKey rows: 2837 Extra: Using where 2 rows in set (0.00 sec) mysql> select * from information_schema.global_status where variable_name… | 0.1953 | +——————-+——————+——-+——+——+———+—————–+ 8 rows in set (0.11 sec) mysql> select * from information_schema.innodb_buffer_pool_stats\G *************************** 1. row *************************** POOL_ID: 0…
