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SHOW PLACEMENT FOR

SHOW PLACEMENT FOR 总结了所有的放置选项,并以规范形式展示指定表、数据库模式或分区的放置信息。

该语句返回的结果集中,Scheduling_State 字段表示 Placement Driver(PD)在调度放置时的当前进度:

  • PENDING:PD 尚未开始调度放置。这可能表示放置规则在语义上是正确的,但当前集群无法满足。例如,若 FOLLOWERS=4,但只有 3 个 TiKV 节点可作为 follower。
  • INPROGRESS:PD 正在调度放置。
  • SCHEDULED:PD 已成功完成放置调度。

语法

ShowStmt
SHOWPLACEMENTFORShowPlacementTarget
ShowPlacementTarget
DatabaseSymDBNameTABLETableNameTABLETableNamePARTITIONIdentifier

示例

CREATE PLACEMENT POLICY p1 PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1" FOLLOWERS=4; ALTER DATABASE test PLACEMENT POLICY=p1; CREATE TABLE t1 (a INT); SHOW PLACEMENT FOR DATABASE test; SHOW PLACEMENT FOR TABLE t1; SHOW CREATE TABLE t1\G CREATE TABLE t3 (a INT) PARTITION BY RANGE (a) (PARTITION p1 VALUES LESS THAN (10), PARTITION p2 VALUES LESS THAN (20)); SHOW PLACEMENT FOR TABLE t3 PARTITION p1\G
Query OK, 0 rows affected (0.02 sec) Query OK, 0 rows affected (0.00 sec) Query OK, 0 rows affected (0.01 sec) +---------------+----------------------------------------------------------------------+------------------+ | Target | Placement | Scheduling_State | +---------------+----------------------------------------------------------------------+------------------+ | DATABASE test | PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1" FOLLOWERS=4 | INPROGRESS | +---------------+----------------------------------------------------------------------+------------------+ 1 row in set (0.00 sec) +---------------+-------------+------------------+ | Target | Placement | Scheduling_State | +---------------+-------------+------------------+ | TABLE test.t1 | FOLLOWERS=4 | INPROGRESS | +---------------+-------------+------------------+ 1 row in set (0.00 sec) ***************************[ 1. row ]*************************** Table | t1 Create Table | CREATE TABLE `t1` ( `a` int DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin /*T![placement] PLACEMENT POLICY=`p1` */ 1 row in set (0.00 sec) ***************************[ 1. row ]*************************** Target | TABLE test.t3 PARTITION p1 Placement | PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1" FOLLOWERS=4 Scheduling_State | PENDING 1 row in set (0.00 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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