ANALYZE [LOCAL | NO_WRITE_TO_BINLOG] TABLE tbl_name[,tbl_name...]

Analyze and store the key distribution for the table. During the analysis, the table is locked with a read lock. This works on MyISAM and BDB tables.

This is equivalent to running myisamchk -a on the table.

MySQL uses the stored key distribution to decide in which order tables should be joined when you perform a join on something other than a constant.

The command returns a table with the following columns:
Column Value
Table Table name
Op Always analyze
Msg_type One of status, error, info, or warning
Msg_text The message

You can check the stored key distribution with the SHOW INDEX command. See section 13.5.3.1 Retrieving Information about Database, Tables, Columns, and Indexes.

If the table hasn't changed since the last ANALYZE TABLE command, the table will not be analyzed again.

Before MySQL 4.1.1, ANALYZE commands are not written to the binary log. Since MySQL 4.1.1 they are written to the binary log unless the optional NO_WRITE_TO_BINLOG keyword (or its alias LOCAL) was used.

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