ANALYZE [NO_WRITE_TO_BINLOG | LOCAL] TABLE
tbl_name [, tbl_name] ...
ANALYZE TABLE analyzes and stores
the key distribution for a table. During the analysis, the table
is locked with a read lock for MyISAM and
InnoDB. This statement works with
MyISAM and InnoDB tables.
For MyISAM tables, this statement is
equivalent to using myisamchk --analyze.
For more information on how the analysis works within
InnoDB, see
Section 13.6.15, “Limits on InnoDB Tables”.
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 Section 12.1.6, “ALTER TABLE Syntax”, and
Section 18.3.3, “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
Section 12.4.5.23, “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.