planner: return error when SPLIT PARTITION TABLE on non-partitioned…

… table (pingcap#17218)

executor/executor_test.go

@@ -4251,6 +4251,9 @@ func (s *testSplitTable) TestShowTableRegion(c *C) {
 	tk.MustExec("set global tidb_scatter_region = 1")
 	atomic.StoreUint32(&ddl.EnableSplitTableRegion, 1)
 	tk.MustExec("create table t_regions (a int key, b int, c int, index idx(b), index idx2(c))")
+	_, err := tk.Exec("split partition table t_regions partition (p1,p2) index idx between (0) and (20000) regions 2;")
+	c.Assert(err.Error(), Equals, plannercore.ErrPartitionClauseOnNonpartitioned.Error())
+
 	// Test show table regions.
 	tk.MustQuery(`split table t_regions between (-10000) and (10000) regions 4;`).Check(testkit.Rows("4 1"))
 	re := tk.MustQuery("show table t_regions regions")

planner/core/planbuilder.go

@@ -2394,6 +2394,9 @@ func (b *PlanBuilder) buildIndexAdvise(node *ast.IndexAdviseStmt) Plan {
 }
 
 func (b *PlanBuilder) buildSplitRegion(node *ast.SplitRegionStmt) (Plan, error) {
+	if node.SplitSyntaxOpt != nil && node.SplitSyntaxOpt.HasPartition && node.Table.TableInfo.Partition == nil {
+		return nil, ErrPartitionClauseOnNonpartitioned
+	}
 	if len(node.IndexName.L) != 0 {
 		return b.buildSplitIndexRegion(node)
 	}