SHOW PLACEMENT

警告：

Placement Rules in SQL 是 TiDB 在 v5.3.0 中引入的实验特性，其语法在 GA 前可能会发生变化，还可能存在 bug。如果你知晓潜在的风险，可通过执行 SET GLOBAL tidb_enable_alter_placement = 1; 来开启该实验特性。

SHOW PLACEMENT 汇总了直接放置 (direct placement) 和放置策略 (placement policy) 中的所有放置选项，并以规范的形式呈现这些选项信息。

语法图

1. ShowStmt ::=
2. "PLACEMENT"

示例

1. CREATE PLACEMENT POLICY p1 PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1" FOLLOWERS=4;
2. CREATE TABLE t1 (a INT) PLACEMENT POLICY=p1;
3. CREATE TABLE t2 (a INT) PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1" FOLLOWERS=4;
4. SHOW PLACEMENT;

1. Query OK, 0 rows affected (0.01 sec)

3. Query OK, 0 rows affected (0.00 sec)

5. Query OK, 0 rows affected (0.00 sec)

7. +---------------+----------------------------------------------------------------------+------------------+
8. | Target        | Placement                                                            | Scheduling_State |
9. +---------------+----------------------------------------------------------------------+------------------+
10. | POLICY p1     | PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1" FOLLOWERS=4 | NULL             |
11. | DATABASE test | PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1" FOLLOWERS=4 | INPROGRESS       |
12. | TABLE test.t1 | PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1" FOLLOWERS=4 | INPROGRESS       |
13. | TABLE test.t2 | PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1" FOLLOWERS=4 | INPROGRESS       |
14. +---------------+----------------------------------------------------------------------+------------------+
15. 4 rows 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