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MySQL 5.5 Reference Manual
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13.7.2.1 ANALYZE TABLE Syntax

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

ANALYZE TABLE performs a key distribution analysis and stores the distribution for the named table or tables. For MyISAM tables, this statement is equivalent to using myisamchk --analyze.

This statement requires SELECT and INSERT privileges for the table.

ANALYZE TABLE works with InnoDB, NDB, and MyISAM tables. It does not work with views.

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 Section 13.1.7, “ALTER TABLE Syntax”, and Section 19.3.3, “Maintenance of Partitions”.

During the analysis, the table is locked with a read lock for InnoDB and MyISAM.

By default, the server writes ANALYZE TABLE statements to the binary log so that they replicate to replication slaves. To suppress logging, specify the optional NO_WRITE_TO_BINLOG keyword or its alias LOCAL.

ANALYZE TABLE Output

ANALYZE TABLE returns a result set with the columns shown in the following table.

ColumnValue
TableThe table name
OpAlways analyze
Msg_typestatus, error, info, note, or warning
Msg_textAn informational message
Key Distribution Analysis

If the table has not changed since the last key distribution analysis, the table is not analyzed again.

MySQL uses the stored key distribution to decide the table join order for joins 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.

For more information on how key distribution analysis works within InnoDB, see Section 14.9.11, “Configuring Optimizer Statistics for InnoDB”. Also see Section 14.9.11.1, “Estimating ANALYZE TABLE Complexity for InnoDB Tables” and Section 14.11.1.7, “Limits on InnoDB Tables”.

To check the stored key distribution cardinality, use the SHOW INDEX statement or the INFORMATION_SCHEMA.STATISTICS table. See Section 13.7.5.23, “SHOW INDEX Syntax”, and Section 21.20, “The INFORMATION_SCHEMA STATISTICS Table”.


User Comments
  Posted by James Day on July 26, 2004
Use mysqlcheck -Aa -uroot -p to run analyze table for all databases and tables (including InnoDB) on a running server. Available in MySQL 3.23.38 and later.
  Posted by Rob Blick on April 27, 2005
Note that ANALYZE TABLE requires SELECT and INSERT privileges, only (LOCK TABLES is not needed).
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