PLACEMENT_POLICIES

PLACEMENT_POLICIES 表展示所有放置策略 (placement policy) 的信息，见 Placement Rules in SQL。

  1. USE information_schema;
  2. DESC placement_policies;
  1. +----------------------+---------------+------+-----+---------+-------+
  2. | Field                | Type          | Null | Key | Default | Extra |
  3. +----------------------+---------------+------+-----+---------+-------+
  4. | POLICY_ID            | bigint(64)    | NO   |     | <null>  |       |
  5. | CATALOG_NAME         | varchar(512)  | NO   |     | <null>  |       |
  6. | POLICY_NAME          | varchar(64)   | NO   |     | <null>  |       |
  7. | PRIMARY_REGION       | varchar(1024) | YES  |     | <null>  |       |
  8. | REGIONS              | varchar(1024) | YES  |     | <null>  |       |
  9. | CONSTRAINTS          | varchar(1024) | YES  |     | <null>  |       |
  10. | LEADER_CONSTRAINTS   | varchar(1024) | YES  |     | <null>  |       |
  11. | FOLLOWER_CONSTRAINTS | varchar(1024) | YES  |     | <null>  |       |
  12. | LEARNER_CONSTRAINTS  | varchar(1024) | YES  |     | <null>  |       |
  13. | SCHEDULE             | varchar(20)   | YES  |     | <null>  |       |
  14. | FOLLOWERS            | bigint(64)    | YES  |     | <null>  |       |
  15. | LEARNERS             | bigint(64)    | YES  |     | <null>  |       |
  16. +----------------------+---------------+------+-----+---------+-------+
  17. 12 rows in set (0.00 sec)

示例

PLACEMENT_POLICIES 表只展示放置策略 (placement policy) 的信息。如需查看所有信息的规范版本（放置策略，以及绑定放置策略的对象），请改用 SHOW PLACEMENT 语句：

  1. CREATE TABLE t1 (a INT);
  2. CREATE PLACEMENT POLICY p1 primary_region="us-east-1" regions="us-east-1";
  3. CREATE TABLE t3 (a INT) PLACEMENT POLICY=p1;
  4. SHOW PLACEMENT; -- 显示所有信息，包含 t3。
  5. SELECT * FROM information_schema.placement_policies; -- 只显示放置策略，不包含 t3。
  1. Query OK, 0 rows affected (0.09 sec)
  3. Query OK, 0 rows affected (0.11 sec)
  5. Query OK, 0 rows affected (0.08 sec)
  7. +---------------+------------------------------------------------+------------------+
  8. | Target        | Placement                                      | Scheduling_State |
  9. +---------------+------------------------------------------------+------------------+
  10. | POLICY p1     | PRIMARY_REGION="us-east-1" REGIONS="us-east-1" | NULL             |
  11. | TABLE test.t3 | PRIMARY_REGION="us-east-1" REGIONS="us-east-1" | SCHEDULED        |
  12. +---------------+------------------------------------------------+------------------+
  13. 2 rows in set (0.00 sec)
  15. +-----------+--------------+-------------+----------------+-----------+-------------+--------------------+----------------------+---------------------+----------+-----------+----------+
  16. | POLICY_ID | CATALOG_NAME | POLICY_NAME | PRIMARY_REGION | REGIONS   | CONSTRAINTS | LEADER_CONSTRAINTS | FOLLOWER_CONSTRAINTS | LEARNER_CONSTRAINTS | SCHEDULE | FOLLOWERS | LEARNERS |
  17. +-----------+--------------+-------------+----------------+-----------+-------------+--------------------+----------------------+---------------------+----------+-----------+----------+
  18. | 1         | def          | p1          | us-east-1      | us-east-1 |             |                    |                      |                     |          | 2         | 0        |
  19. +-----------+--------------+-------------+----------------+-----------+-------------+--------------------+----------------------+---------------------+----------+-----------+----------+
  20. 1 rows in set (0.00 sec)