ANALYZE TABLE

Syntax

ANALYZE [NO_WRITE_TO_BINLOG | LOCAL] TABLE tbl_name [,tbl_name ...] 
  [PERSISTENT FOR [ALL|COLUMNS ([col_name [,col_name ...]])] 
    [INDEXES ([index_name [,index_name ...]])]]

Contents

  1. Syntax
  2. Description
  3. See Also

Description

ANALYZE TABLE analyzes and stores the key distribution for a table (index statistics). During the analysis, the table is locked with a read lock for MyISAM. For InnoDB the table is locked with a write lock. This statement works with MyISAM, Aria 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 InnoDB Restrictions

MariaDB 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.

By default, ANALYZE TABLE statements are written to the binary log and will be replicated. The NO_WRITE_TO_BINLOG keyword (LOCAL is an alias) will ensure the statement is not written to the binary log.

ANALYZE TABLE is also supported for partitioned tables. You can use ALTER TABLE ... ANALYZE PARTITION to analyze one or more partitions.

MariaDB 10.0.1 extended ANALYZE TABLE to support engine-independent statistics.

Engine-independent statistics is collected by doing full table and full index scans, and can be quite expensive.

The syntax for ANALYZE TABLE has been extended in MariaDB 10.0.1 to allow one to collect statistics only for particular columns or indexes, using PERSISTENT FOR:

Note that statistics for blob and text columns are not collected. If explicitly specified, a warning is returned.

-- update all engine-independent statistics for all columns and indexes
ANALYZE TABLE tbl PERSISTENT FOR ALL;

-- update specific columns and indexes:
ANALYZE TABLE tbl PERSISTENT FOR COLUMNS (col1,col2,...) INDEXES (idx1,idx2,...);

-- empty lists are allowed:
ANALYZE TABLE tbl PERSISTENT FOR COLUMNS (col1,col2,...) INDEXES ();
ANALYZE TABLE tbl PERSISTENT FOR COLUMNS () INDEXES (idx1,idx2,...);

-- the following will only update mysql.table_stat fields:
ANALYZE TABLE tbl PERSISTENT FOR COLUMNS () INDEXES ();

-- with use_stat_tables != NEVER a simple ANALYZE TABLE 
-- collects engine-independent statistics for all columns and indexes.
SET SESSION use_stat_tables='COMPLEMENTARY';
ANALYZE TABLE tbl;

The PERSISTENT FOR is required to update the engine-independent statistics even if the table has the option STATS_PERSISTENT=1.

Since MariaDB 5.3, the Aria storage engine supports progress reporting for this statement.

See Also

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