ANALYZE TABLE Syntax
ANALYZE TABLE analyzes and stores the key distribution for a table. During the analysis, the table is locked with a read lock for InnoDB and MyISAM. This statement works with InnoDB, NDB, and MyISAM tables. For MyISAM tables, this statement is equivalent to using myisamchk --analyze.
For more information on how the analysis works within InnoDB, see , "Persistent Optimizer Statistics for InnoDB Tables" and , "Limits on InnoDB Tables". In particular, when you enable the innodb_analyze_is_persistent option, you must run ANALYZE TABLE after loading substantial data into an InnoDB table, or creating a new index for one.
MySQL uses the stored key distribution to decide the order in which tables should be joined when you perform a join on something other than a constant. In addition, key distributions can be used when deciding which indexes to use for a specific table within a query.
This statement requires SELECT and INSERT privileges for the table.
ANALYZE TABLE is supported for partitioned tables, and you can use ALTER TABLE ... ANALYZE PARTITION to analyze one or more partitions; for more information, see , "ALTER TABLE Syntax", and , "Maintenance of Partitions".
ANALYZE TABLE returns a result set with the following columns.
| Column | Value |
|---|---|
Table
| The table name |
Op
| Always analyze
|
Msg_type
| status, error, info, note, or warning
|
Msg_text
| An informational message |
You can check the stored key distribution with the SHOW INDEX statement. See , "SHOW INDEX Syntax".
If the table has not changed since the last ANALYZE TABLE statement, the table is not analyzed again.
By default, ANALYZE TABLE statements are written to the binary log so that they will be replicated to replication slaves. Logging can be suppressed with the optional NO_WRITE_TO_BINLOG keyword or its alias LOCAL.