SHOW STATS_LOCKED

SHOW STATS_LOCKED 语句显示统计信息被锁定的表。

语法图

ShowStatsLockedStmt
SHOWSTATS_LOCKEDShowLikeOrWhereOpt
ShowLikeOrWhereOpt
LIKESimpleExprWHEREExpression

示例

创建表 t,插入一些数据,在未锁定表 t 的统计信息的情况下成功执行 ANALYZE 语句。

mysql> CREATE TABLE t(a INT, b INT); Query OK, 0 rows affected (0.03 sec) mysql> INSERT INTO t VALUES (1,2), (3,4), (5,6), (7,8); Query OK, 4 rows affected (0.00 sec) Records: 4 Duplicates: 0 Warnings: 0 mysql> ANALYZE TABLE t; Query OK, 0 rows affected, 1 warning (0.02 sec) mysql> SHOW WARNINGS; +-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Level | Code | Message | +-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t, reason to use this rate is "Row count in stats_meta is much smaller compared with the row count got by PD, use min(1, 15000/4) as the sample-rate=1" | +-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)

锁定表 t 的统计信息,执行 SHOW STATS_LOCKED 语句,显示表 t 的统计信息被锁定。

mysql> LOCK STATS t; Query OK, 0 rows affected (0.00 sec) mysql> SHOW STATS_LOCKED; +---------+------------+----------------+--------+ | Db_name | Table_name | Partition_name | Status | +---------+------------+----------------+--------+ | test | t | | locked | +---------+------------+----------------+--------+ 1 row in set (0.01 sec)

MySQL 兼容性

该语句是 TiDB 对 MySQL 语法的扩展。

另请参阅

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