ALTER PLACEMENT POLICY

ALTER PLACEMENT POLICY is used to modify existing placement policies that have previously been created. All the tables and partitions which use the placement policy will automatically be updated.

Synopsis

AlterPolicyStmt ::=
    "ALTER" "PLACEMENT" "POLICY" IfExists PolicyName PlacementOptionList

PolicyName ::=
    Identifier

PlacementOptionList ::=
    DirectPlacementOption
|   PlacementOptionList DirectPlacementOption
|   PlacementOptionList ',' DirectPlacementOption

DirectPlacementOption ::=
    "PRIMARY_REGION" EqOpt stringLit
|   "REGIONS" EqOpt stringLit
|   "FOLLOWERS" EqOpt LengthNum
|   "VOTERS" EqOpt LengthNum
|   "LEARNERS" EqOpt LengthNum
|   "SCHEDULE" EqOpt stringLit
|   "CONSTRAINTS" EqOpt stringLit
|   "LEADER_CONSTRAINTS" EqOpt stringLit
|   "FOLLOWER_CONSTRAINTS" EqOpt stringLit
|   "VOTER_CONSTRAINTS" EqOpt stringLit
|   "LEARNER_CONSTRAINTS" EqOpt stringLit

Examples

CREATE PLACEMENT POLICY p1 PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1";
ALTER PLACEMENT POLICY p1 PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1,us-west-2" FOLLOWERS=4;
SHOW CREATE PLACEMENT POLICY p1\G

Query OK, 0 rows affected (0.08 sec)

Query OK, 0 rows affected (0.10 sec)

*************************** 1. row ***************************
       Policy: p1
Create Policy: CREATE PLACEMENT POLICY `p1` PRIMARY_REGION="us-east-1" REGIONS="us-east-1,us-west-1,us-west-2" FOLLOWERS=4
1 row in set (0.00 sec)

MySQL compatibility

This statement is a TiDB extension to MySQL syntax.

See also

• Placement Rules in SQL
• SHOW PLACEMENT
• CREATE PLACEMENT POLICY
• DROP PLACEMENT POLICY