ddl: fix issue pre_split_regions table option doesn't work in the partition table.

ddl/ddl_api.go

@@ -1703,7 +1703,7 @@ func (d *ddl) preSplitAndScatter(ctx sessionctx.Context, tbInfo *model.TableInfo
 		scatterRegion = variable.TiDBOptOn(val)
 	}
 	if pi != nil {
-		preSplit = func() { splitPartitionTableRegion(ctx, sp, pi, scatterRegion) }
+		preSplit = func() { splitPartitionTableRegion(ctx, sp, tbInfo, pi, scatterRegion) }
 	} else {
 		preSplit = func() { splitTableRegion(ctx, sp, tbInfo, scatterRegion) }
 	}

ddl/split_region.go

@@ -24,13 +24,19 @@ import (
 	"go.uber.org/zap"
 )
 
-func splitPartitionTableRegion(ctx sessionctx.Context, store kv.SplittableStore, pi *model.PartitionInfo, scatter bool) {
+func splitPartitionTableRegion(ctx sessionctx.Context, store kv.SplittableStore, tbInfo *model.TableInfo, pi *model.PartitionInfo, scatter bool) {
 	// Max partition count is 4096, should we sample and just choose some of the partition to split?
 	regionIDs := make([]uint64, 0, len(pi.Definitions))
 	ctxWithTimeout, cancel := context.WithTimeout(context.Background(), ctx.GetSessionVars().GetSplitRegionTimeout())
 	defer cancel()
-	for _, def := range pi.Definitions {
-		regionIDs = append(regionIDs, splitRecordRegion(ctxWithTimeout, store, def.ID, scatter))
+	if tbInfo.ShardRowIDBits > 0 && tbInfo.PreSplitRegions > 0 {
+		for _, def := range pi.Definitions {
+			regionIDs = append(regionIDs, preSplitPhysicalTableByShardRowID(ctxWithTimeout, store, tbInfo, def.ID, scatter)...)
+		}
+	} else {
+		for _, def := range pi.Definitions {
+			regionIDs = append(regionIDs, splitRecordRegion(ctxWithTimeout, store, def.ID, scatter))
+		}
 	}
 	if scatter {
 		waitScatterRegionFinish(ctxWithTimeout, store, regionIDs...)
@@ -40,17 +46,18 @@ func splitPartitionTableRegion(ctx sessionctx.Context, store kv.SplittableStore,
 func splitTableRegion(ctx sessionctx.Context, store kv.SplittableStore, tbInfo *model.TableInfo, scatter bool) {
 	ctxWithTimeout, cancel := context.WithTimeout(context.Background(), ctx.GetSessionVars().GetSplitRegionTimeout())
 	defer cancel()
+	var regionIDs []uint64
 	if tbInfo.ShardRowIDBits > 0 && tbInfo.PreSplitRegions > 0 {
-		splitPreSplitedTable(ctxWithTimeout, store, tbInfo, scatter)
+		regionIDs = preSplitPhysicalTableByShardRowID(ctxWithTimeout, store, tbInfo, tbInfo.ID, scatter)
 	} else {
-		regionID := splitRecordRegion(ctxWithTimeout, store, tbInfo.ID, scatter)
-		if scatter {
-			waitScatterRegionFinish(ctxWithTimeout, store, regionID)
-		}
+		regionIDs = append(regionIDs, splitRecordRegion(ctxWithTimeout, store, tbInfo.ID, scatter))
+	}
+	if scatter {
+		waitScatterRegionFinish(ctxWithTimeout, store, regionIDs...)
 	}
 }
 
-func splitPreSplitedTable(ctx context.Context, store kv.SplittableStore, tbInfo *model.TableInfo, scatter bool) {
+func preSplitPhysicalTableByShardRowID(ctx context.Context, store kv.SplittableStore, tbInfo *model.TableInfo, physicalID int64, scatter bool) []uint64 {
 	// Example:
 	// ShardRowIDBits = 4
 	// PreSplitRegions = 2
@@ -78,9 +85,10 @@ func splitPreSplitedTable(ctx context.Context, store kv.SplittableStore, tbInfo
 	step := int64(1 << (tbInfo.ShardRowIDBits - tbInfo.PreSplitRegions))
 	max := int64(1 << tbInfo.ShardRowIDBits)
 	splitTableKeys := make([][]byte, 0, 1<<(tbInfo.PreSplitRegions))
+	splitTableKeys = append(splitTableKeys, tablecodec.GenTablePrefix(physicalID))
 	for p := step; p < max; p += step {
 		recordID := p << (64 - tbInfo.ShardRowIDBits - 1)
-		recordPrefix := tablecodec.GenTableRecordPrefix(tbInfo.ID)
+		recordPrefix := tablecodec.GenTableRecordPrefix(physicalID)
 		key := tablecodec.EncodeRecordKey(recordPrefix, kv.IntHandle(recordID))
 		splitTableKeys = append(splitTableKeys, key)
 	}
@@ -91,9 +99,7 @@ func splitPreSplitedTable(ctx context.Context, store kv.SplittableStore, tbInfo
 			zap.Stringer("table", tbInfo.Name), zap.Int("successful region count", len(regionIDs)), zap.Error(err))
 	}
 	regionIDs = append(regionIDs, splitIndexRegion(store, tbInfo, scatter)...)
-	if scatter {
-		waitScatterRegionFinish(ctx, store, regionIDs...)
-	}
+	return regionIDs
 }
 
 func splitRecordRegion(ctx context.Context, store kv.SplittableStore, tableID int64, scatter bool) uint64 {

executor/executor_test.go

@@ -4410,6 +4410,23 @@ func (s *testSplitTable) TestShowTableRegion(c *C) {
 	c.Assert(rows[1][1], Equals, fmt.Sprintf("t_%d_r_2305843009213693952", tbl.Meta().ID))
 	c.Assert(rows[2][1], Equals, fmt.Sprintf("t_%d_r_4611686018427387904", tbl.Meta().ID))
 	c.Assert(rows[3][1], Equals, fmt.Sprintf("t_%d_r_6917529027641081856", tbl.Meta().ID))
+
+	// Test pre-split table region when create table.
+	tk.MustExec("drop table if exists pt_pre")
+	tk.MustExec("create table pt_pre (a int, b int) shard_row_id_bits = 2 pre_split_regions=2 partition by hash(a) partitions 3;")
+	re = tk.MustQuery("show table pt_pre regions")
+	rows = re.Rows()
+	// Table t_regions should have 4 regions now.
+	c.Assert(len(rows), Equals, 12)
+	tbl = testGetTableByName(c, tk.Se, "test", "pt_pre")
+	pi := tbl.Meta().GetPartitionInfo().Definitions
+	c.Assert(len(pi), Equals, 3)
+	for i, p := range pi {
+		c.Assert(rows[1+4*i][1], Equals, fmt.Sprintf("t_%d_r_2305843009213693952", p.ID))
+		c.Assert(rows[2+4*i][1], Equals, fmt.Sprintf("t_%d_r_4611686018427387904", p.ID))
+		c.Assert(rows[3+4*i][1], Equals, fmt.Sprintf("t_%d_r_6917529027641081856", p.ID))
+	}
+
 	defer atomic.StoreUint32(&ddl.EnableSplitTableRegion, 0)
 
 	// Test split partition table.