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 ...]])]]
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
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 number of duplicates
ANALYZE TABLE
uses a buffer of sort_buffer_size bytes per column. You can increase speed ofANALYZE TABLE
a bit by increasing this variable.