--- title: ANALYZE | TiDB SQL Statement Reference summary: An overview of the usage of ANALYZE for the TiDB database. aliases: ['/docs/dev/sql-statements/sql-statement-analyze-table/','/docs/dev/reference/sql/statements/analyze-table/'] --- # ANALYZE This statement updates the statistics that TiDB builds on tables and indexes. It is recommended to run `ANALYZE` after performing a large batch update or import of records, or when you notice that query execution plans are sub-optimal. TiDB will also automatically update its statistics over time as it discovers that they are inconsistent with its own estimates. Currently, TiDB collects statistical information in two ways: full collection (implemented using the `ANALYZE TABLE` statement) and incremental collection (implemented using the `ANALYZE INCREMENTAL TABLE` statement). For detailed usage of these two statements, refer to [introduction to statistics](/statistics.md) ## Synopsis ```ebnf+diagram AnalyzeTableStmt ::= 'ANALYZE' ( 'TABLE' ( TableNameList ( 'ALL COLUMNS' | 'PREDICATE COLUMNS' ) | TableName ( 'INDEX' IndexNameList? | AnalyzeColumnOption | 'PARTITION' PartitionNameList ( 'INDEX' IndexNameList? | AnalyzeColumnOption )? )? ) | 'INCREMENTAL' 'TABLE' TableName ( 'PARTITION' PartitionNameList )? 'INDEX' IndexNameList? ) AnalyzeOptionListOpt AnalyzeOptionListOpt ::= ( WITH AnalyzeOptionList )? AnalyzeOptionList ::= AnalyzeOption ( ',' AnlyzeOption )* AnalyzeOption ::= ( NUM ( 'BUCKETS' | 'TOPN' | ( 'CMSKETCH' ( 'DEPTH' | 'WIDTH' ) ) | 'SAMPLES' ) ) | ( FLOATNUM 'SAMPLERATE' ) AnalyzeColumnOption ::= ( 'ALL COLUMNS' | 'PREDICATE COLUMNS' | 'COLUMNS' ColumnNameList ) TableNameList ::= TableName (',' TableName)* TableName ::= Identifier ( '.' Identifier )? ColumnNameList ::= Identifier ( ',' Identifier )* IndexNameList ::= Identifier ( ',' Identifier )* PartitionNameList ::= Identifier ( ',' Identifier )* ``` ## Examples ```sql mysql> CREATE TABLE t1 (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, c1 INT NOT NULL); Query OK, 0 rows affected (0.11 sec) mysql> INSERT INTO t1 (c1) VALUES (1),(2),(3),(4),(5); Query OK, 5 rows affected (0.03 sec) Records: 5 Duplicates: 0 Warnings: 0 mysql> ALTER TABLE t1 ADD INDEX (c1); Query OK, 0 rows affected (0.30 sec) mysql> EXPLAIN SELECT * FROM t1 WHERE c1 = 3; +------------------------+---------+-----------+------------------------+---------------------------------------------+ | id | estRows | task | access object | operator info | +------------------------+---------+-----------+------------------------+---------------------------------------------+ | IndexReader_6 | 10.00 | root | | index:IndexRangeScan_5 | | └─IndexRangeScan_5 | 10.00 | cop[tikv] | table:t1, index:c1(c1) | range:[3,3], keep order:false, stats:pseudo | +------------------------+---------+-----------+------------------------+---------------------------------------------+ 2 rows in set (0.00 sec) mysql> analyze table t1; Query OK, 0 rows affected (0.13 sec) mysql> EXPLAIN SELECT * FROM t1 WHERE c1 = 3; +------------------------+---------+-----------+------------------------+-------------------------------+ | id | estRows | task | access object | operator info | +------------------------+---------+-----------+------------------------+-------------------------------+ | IndexReader_6 | 1.00 | root | | index:IndexRangeScan_5 | | └─IndexRangeScan_5 | 1.00 | cop[tikv] | table:t1, index:c1(c1) | range:[3,3], keep order:false | +------------------------+---------+-----------+------------------------+-------------------------------+ 2 rows in set (0.00 sec) ``` ## MySQL compatibility TiDB differs from MySQL in **both** the statistics it collects and how it makes use of statistics during query execution. While this statement is syntactically similar to MySQL, the following differences apply: 1. TiDB might not include very recently committed changes when running `ANALYZE TABLE`. After a batch-update of rows, you might need to `sleep(1)` before executing `ANALYZE TABLE` in order for the statistics update to reflect these changes. [#16570](https://github.com/pingcap/tidb/issues/16570). 2. `ANALYZE TABLE` takes significantly longer to execute in TiDB than MySQL. This performance difference can be partially mitigated by enabling fast analyze with `SET GLOBAL tidb_enable_fast_analyze=1`. Fast analyze makes use of sampling, leading to less accurate statistics. Its usage is still considered experimental. MySQL does not support the `ANALYZE INCREMENTAL TABLE` statement. TiDB supports incremental collection of statistics. For detailed usage, refer to [incremental collection](/statistics.md#incremental-collection). ## See also * [EXPLAIN](/sql-statements/sql-statement-explain.md) * [EXPLAIN ANALYZE](/sql-statements/sql-statement-explain-analyze.md)