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
Description
ANALYZE TABLE analyzes and stores the key distribution for a
table (index statistics). This statement works with MyISAM, Aria and InnoDB tables. During the analysis, InnoDB will allow reads/writes, and MyISAM/Aria reads/inserts. For MyISAM tables, this statement is equivalent to using myisamchk --analyze.
For more information on how the analysis works within InnoDB, see InnoDB Limitations.
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.
From MariaDB 10.3.19, ANALYZE TABLE statements are not logged to the binary log if read_only is set. See also Read-Only Replicas.
ANALYZE TABLE is also supported for partitioned tables. You
can use ALTER TABLE ... ANALYZE PARTITION to analyze one or
more partitions.
The Aria storage engine supports progress reporting for the ANALYZE TABLE statement.
Engine-Independent Statistics / PERSISTENT FOR
ANALYZE TABLE supports engine-independent statistics. See Engine-Independent Table Statistics: Collecting Statistics with the ANALYZE TABLE Statement for more information.
Useful Variables
For calculating the number of duplicates, ANALYZE TABLE uses a buffer of sort_buffer_size bytes per column. You can slightly increase the speed of ANALYZE TABLE by increasing this variable.
Examples
-- 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_stats fields: ANALYZE TABLE tbl PERSISTENT FOR COLUMNS () INDEXES (); -- when use_stat_tables is set to 'COMPLEMENTARY' or 'PREFERABLY', -- a simple ANALYZE TABLE collects engine-independent statistics for all columns and indexes. SET SESSION use_stat_tables='COMPLEMENTARY'; ANALYZE TABLE tbl;
