ddl: LINEAR HASH as HASH partitioned table (#38451)

close #38450

ddl/db_partition_test.go

@@ -383,7 +383,14 @@ func TestCreateTableWithHashPartition(t *testing.T) {
 ) PARTITION BY HASH(store_id) PARTITIONS 102400000000;`, errno.ErrTooManyPartitions)
 
 	tk.MustExec("CREATE TABLE t_linear (a int, b varchar(128)) PARTITION BY LINEAR HASH(a) PARTITIONS 4")
-	tk.MustGetErrCode("select * from t_linear partition (p0)", errno.ErrPartitionClauseOnNonpartitioned)
+	tk.MustQuery(`show warnings`).Check(testkit.Rows("Warning 8200 LINEAR HASH is not supported, using non-linear HASH instead"))
+	tk.MustQuery(`show create table t_linear`).Check(testkit.Rows("" +
+		"t_linear CREATE TABLE `t_linear` (\n" +
+		"  `a` int(11) DEFAULT NULL,\n" +
+		"  `b` varchar(128) DEFAULT NULL\n" +
+		") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin\n" +
+		"PARTITION BY HASH (`a`) PARTITIONS 4"))
+	tk.MustQuery("select * from t_linear partition (p0)").Check(testkit.Rows())
 
 	tk.MustExec(`CREATE TABLE t_sub (a int, b varchar(128)) PARTITION BY RANGE( a ) SUBPARTITION BY HASH( a )
                                    SUBPARTITIONS 2 (

ddl/partition.go

@@ -425,8 +425,11 @@ func buildTablePartitionInfo(ctx sessionctx.Context, s *ast.PartitionOptions, tb
 		}
 	case model.PartitionTypeHash:
 		// Partition by hash is enabled by default.
-		// Note that linear hash is not enabled.
-		if !s.Linear && s.Sub == nil {
+		// Note that linear hash is simply ignored, and creates non-linear hash.
+		if s.Linear {
+			ctx.GetSessionVars().StmtCtx.AppendWarning(dbterror.ErrUnsupportedCreatePartition.GenWithStack("LINEAR HASH is not supported, using non-linear HASH instead"))
+		}
+		if s.Sub == nil {
 			enable = true
 		}
 	case model.PartitionTypeList:

executor/builder.go

@@ -1089,7 +1089,7 @@ func (b *executorBuilder) setTelemetryInfo(v *plannercore.DDL) {
 				}
 			}
 		case model.PartitionTypeHash:
-			if !p.Linear && p.Sub == nil {
+			if p.Sub == nil {
 				b.Ti.PartitionTelemetry.UseTablePartitionHash = true
 			}
 		case model.PartitionTypeList: