ANALYZE [NO_WRITE_TO_BINLOG | LOCAL] TABLEtbl_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
BDB
. For InnoDB
the table
is locked with a write lock. This statement works with
MyISAM
, BDB
, and (as of
MySQL 4.0.13) 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 13.2.15, “Restrictions on InnoDB
Tables”.
MySQL Enterprise. For expert advice on optimizing tables, subscribe to the MySQL Enterprise Monitor. For more information, see http://www.mysql.com/products/enterprise/advisors.html.
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
returns a result
set with the following columns.
Column | Value |
Table |
The table name |
Op |
Always analyze
|
Msg_type |
status , error ,
info , or warning
|
Msg_text |
An informational message |
You can check the stored key distribution with the
SHOW INDEX
statement. See
Section 12.4.5.13, “SHOW INDEX
Syntax”.
If the table has not changed since the last
ANALYZE TABLE
statement, the
table is not analyzed again.
Before MySQL 4.1.1, ANALYZE TABLE
statements are not written to the binary log. As of MySQL 4.1.1,
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
.
User Comments
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.
Note that ANALYZE TABLE requires SELECT and INSERT privileges, only (LOCK TABLES is not needed).
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