ALTER TABLE t PARTITION BY gives error when specifying PLACEMENT POLICY

[mjonss]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

create placement policy pp1 followers=1;
create table t (a int);
alter table t partition by range (a) (partition p0 values less than (1000000), partition pMax values less than (maxvalue) placement policy pp1);

2. What did you expect to see? (Required)

tidb> create placement policy pp1 followers=1;
Query OK, 0 rows affected (0.09 sec)

tidb> create table t (a int);
Query OK, 0 rows affected (0.09 sec)

tidb> alter table t partition by range (a) (partition p0 values less than (1000000), partition pMax values less than (maxvalue) placement policy pp1);
Query OK, 0 rows affected, 1 warning (0.05 sec)

3. What did you see instead (Required)

tidb> create placement policy pp1 followers=1;
Query OK, 0 rows affected (0.09 sec)

tidb> create table t (a int);
Query OK, 0 rows affected (0.09 sec)

tidb> alter table t partition by range (a) (partition p0 values less than (1000000), partition pMax values less than (maxvalue) placement policy pp1);
ERROR 8239 (HY000): Unknown placement policy '(Policy ID 0)'

4. What is your TiDB version? (Required)

tidb_version(): Release Version: v7.6.0-alpha
Edition: Community
Git Commit Hash: 625dc4e3cd5d7ebaba592e6a3b8a5697cb28194a
Git Branch: heads/refs/tags/v7.6.0-alpha
UTC Build Time: 2023-11-14 14:26:02
GoVersion: go1.21.3
Race Enabled: false
Check Table Before Drop: false
Store: tikv

[mjonss]

Issue is that the mapping from Placement Policy name to ID is not done, fixed by:

diff --git a/pkg/ddl/ddl_api.go b/pkg/ddl/ddl_api.go
index 2c04151962..82eec78c04 100644
--- a/pkg/ddl/ddl_api.go
+++ b/pkg/ddl/ddl_api.go
@@ -4376,6 +4376,10 @@ func (d *ddl) AlterTablePartitioning(ctx sessionctx.Context, ident ast.Ident, sp
        }
        newPartInfo := newMeta.Partition
 
+       if err = handlePartitionPlacement(ctx, newPartInfo); err != nil {
+               return errors.Trace(err)
+       }
+
        if err = d.assignPartitionIDs(newPartInfo.Definitions); err != nil {
                return errors.Trace(err)
        }