STATS_SAMPLE_PAGES: specifies the number of index pages to sample when estimating cardinality and other statistics for an indexed column.Ĭheck the Status of Statistics from Persistent SettingĬheck status of Statistics from mysql.innodb_table_stats and mysql.innodb_index_stats Value 1 means enabled and 0 means disabled. STATS_AUTO_RECALC: used for automatically recalculate persistent statistics for an InnoDB table. This is achieved by setting optimizertrace'enabledon'. (innodb_stats_persistent parameter for global setting). To trace the MySQL optimizer, you have to turn it on for your session. STATS_PERSISTENT: enable persistent statistics for an InnoDB table. Following clauses used in syntax: STATS_PERSISTENT, STATS_AUTO_RECALC, STATS_SAMPLE_PAGES. You can define the setting while creating table in Create statement.
Running SHOW TABLE STATUS, SHOW INDEX, or querying the INFORMATION_SCHEMA.TABLES or INFORMATION_SCHEMA.STATISTICS tables with the innodb_stats_on_metadata option enabled.Ĭonfigure Persistent setting at table level It will stored stats in memory and go away when MySQL is rebooted.Ģ. There is some option for the optimizer on MySQL 5. default, Reset every optimization to its default value optname default, Set the named optimization to its default value optname off, Disable the named. Note: Increase the value improves the accuracy of index statistics, which improve the query execution plan, at the cost of increased I/O during the execution.Įnable the Non-Persistent Optimizer Setting The optimizer is used to generate an execution plan on how it execute the query. It is used for number of index pages to sample when estimating cardinality and other statistics for an indexed column. Innodb_stats_auto_recalc is enabled by default. It's used to control whether statistics are updated automatically after DML changes to a table happens(10% DML operation happens in table). Enable the Persistent setting: (Default is enabled) Note: Persistent optimizer statistics were introduced in MySQL 5.6.2 and were made the default in MySQL 5.6.6 (innodb_stats_persistent=ON).Ĭonfigure the following parameter for enable the persistent optimizer setting: Non-persistent : Means after restart the MySQL Server your stats lost and recomputed during table access in memory. Persistent : Means after restart the MySQL Server your stats remain persistent for InnonDB Tables offers more plan stability and consistent query performance.Ģ. In MySQL, two type of stats gather you can configure:ġ. I just did it on my VPS after that the mysql process (using top command) uses less memory.
#Mysql optimizer turn off free#
It should free memory and optimize your MySQL performance.
#Mysql optimizer turn off update#
Configure & update the Optimizer Stats gather in MySQL If your MySQL databases uses MyISAM instead of InnoDB you should turn the last one Off.
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