*: support a region divided into multiple regions (#11739)

ddl/split_region.go

@@ -14,6 +14,8 @@
 package ddl
 
 import (
+	"context"
+
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/tablecodec"
@@ -68,19 +70,20 @@ func splitPreSplitedTable(store kv.SplitableStore, tbInfo *model.TableInfo, scat
 	// And the max _tidb_rowid is 9223372036854775807, it won't be negative number.
 
 	// Split table region.
-	regionIDs := make([]uint64, 0, 1<<(tbInfo.PreSplitRegions)+len(tbInfo.Indices))
 	step := int64(1 << (tbInfo.ShardRowIDBits - tbInfo.PreSplitRegions))
 	max := int64(1 << tbInfo.ShardRowIDBits)
+	splitTableKeys := make([][]byte, 0, 1<<(tbInfo.PreSplitRegions))
 	for p := int64(step); p < max; p += step {
 		recordID := p << (64 - tbInfo.ShardRowIDBits - 1)
 		recordPrefix := tablecodec.GenTableRecordPrefix(tbInfo.ID)
 		key := tablecodec.EncodeRecordKey(recordPrefix, recordID)
-		regionID, err := store.SplitRegion(key, scatter)
-		if err != nil {
-			logutil.BgLogger().Warn("[ddl] pre split table region failed", zap.Int64("recordID", recordID), zap.Error(err))
-		} else {
-			regionIDs = append(regionIDs, regionID)
-		}
+		splitTableKeys = append(splitTableKeys, key)
+	}
+	var err error
+	regionIDs, err := store.SplitRegions(context.Background(), splitTableKeys, scatter)
+	if err != nil {
+		logutil.BgLogger().Warn("[ddl] pre split some table regions failed",
+			zap.Stringer("table", tbInfo.Name), zap.Int("successful region count", len(regionIDs)), zap.Error(err))
 	}
 	regionIDs = append(regionIDs, splitIndexRegion(store, tbInfo, scatter)...)
 	if scatter {
@@ -90,26 +93,27 @@ func splitPreSplitedTable(store kv.SplitableStore, tbInfo *model.TableInfo, scat
 
 func splitRecordRegion(store kv.SplitableStore, tableID int64, scatter bool) uint64 {
 	tableStartKey := tablecodec.GenTablePrefix(tableID)
-	regionID, err := store.SplitRegion(tableStartKey, scatter)
+	regionIDs, err := store.SplitRegions(context.Background(), [][]byte{tableStartKey}, scatter)
 	if err != nil {
 		// It will be automatically split by TiKV later.
 		logutil.BgLogger().Warn("[ddl] split table region failed", zap.Error(err))
 	}
-	return regionID
+	if len(regionIDs) == 1 {
+		return regionIDs[0]
+	}
+	return 0
 }
 
 func splitIndexRegion(store kv.SplitableStore, tblInfo *model.TableInfo, scatter bool) []uint64 {
-	regionIDs := make([]uint64, 0, len(tblInfo.Indices))
+	splitKeys := make([][]byte, 0, len(tblInfo.Indices))
 	for _, idx := range tblInfo.Indices {
 		indexPrefix := tablecodec.EncodeTableIndexPrefix(tblInfo.ID, idx.ID)
-		regionID, err := store.SplitRegion(indexPrefix, scatter)
-		if err != nil {
-			logutil.BgLogger().Warn("[ddl] pre split table index region failed",
-				zap.Stringer("table", tblInfo.Name),
-				zap.Stringer("index", idx.Name),
-				zap.Error(err))
-		}
-		regionIDs = append(regionIDs, regionID)
+		splitKeys = append(splitKeys, indexPrefix)
+	}
+	regionIDs, err := store.SplitRegions(context.Background(), splitKeys, scatter)
+	if err != nil {
+		logutil.BgLogger().Warn("[ddl] pre split some table index regions failed",
+			zap.Stringer("table", tblInfo.Name), zap.Int("successful region count", len(regionIDs)), zap.Error(err))
 	}
 	return regionIDs
 }

executor/executor_test.go

@@ -2153,7 +2153,7 @@ func (s *testSuiteP1) TestBatchPointGetRepeatableRead(c *C) {
 }
 
 func (s *testSuite4) TestSplitRegionTimeout(c *C) {
-	c.Assert(failpoint.Enable("github.com/pingcap/tidb/executor/mockSplitRegionTimeout", `return(true)`), IsNil)
+	c.Assert(failpoint.Enable("github.com/pingcap/tidb/store/tikv/MockSplitRegionTimeout", `return(true)`), IsNil)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 	tk.MustExec("drop table if exists t")
@@ -2162,7 +2162,7 @@ func (s *testSuite4) TestSplitRegionTimeout(c *C) {
 	tk.MustExec(`set @@tidb_wait_split_region_timeout=1`)
 	// result 0 0 means split 0 region and 0 region finish scatter regions before timeout.
 	tk.MustQuery(`split table t between (0) and (10000) regions 10`).Check(testkit.Rows("0 0"))
-	c.Assert(failpoint.Disable("github.com/pingcap/tidb/executor/mockSplitRegionTimeout"), IsNil)
+	c.Assert(failpoint.Disable("github.com/pingcap/tidb/store/tikv/MockSplitRegionTimeout"), IsNil)
 }
 
 func (s *testSuiteP1) TestRow(c *C) {
@@ -4050,7 +4050,7 @@ func (s *testSuiteP1) TestReadPartitionedTable(c *C) {
 func (s *testSuiteP1) TestSplitRegion(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
-	tk.MustExec("drop table if exists t")
+	tk.MustExec("drop table if exists t, t1")
 	tk.MustExec("create table t(a varchar(100),b int, index idx1(b,a))")
 	tk.MustExec(`split table t index idx1 by (10000,"abcd"),(10000000);`)
 	_, err := tk.Exec(`split table t index idx1 by ("abcd");`)
@@ -4127,8 +4127,13 @@ func (s *testSuiteP1) TestSplitRegion(c *C) {
 	c.Assert(err, NotNil)
 	c.Assert(err.Error(), Equals, "Split table `t` region step value should more than 1000, step 10 is invalid")
 
-	// Test split region by syntax
+	// Test split region by syntax.
 	tk.MustExec(`split table t by (0),(1000),(1000000)`)
+
+	// Test split region twice to test for multiple batch split region requests.
+	tk.MustExec("create table t1(a int, b int)")
+	tk.MustQuery("split table t1 between(0) and (10000) regions 10;").Check(testkit.Rows("9 1"))
+	tk.MustQuery("split table t1 between(10) and (10010) regions 5;").Check(testkit.Rows("4 1"))
 }
 
 func (s *testSuite) TestShowTableRegion(c *C) {

executor/split.go

@@ -23,7 +23,6 @@ import (
 
 	"github.com/cznic/mathutil"
 	"github.com/pingcap/errors"
-	"github.com/pingcap/failpoint"
 	"github.com/pingcap/kvproto/pkg/metapb"
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/parser/mysql"
@@ -94,27 +93,18 @@ func (e *SplitIndexRegionExec) splitIndexRegion(ctx context.Context) error {
 	start := time.Now()
 	ctxWithTimeout, cancel := context.WithTimeout(ctx, e.ctx.GetSessionVars().GetSplitRegionTimeout())
 	defer cancel()
-	regionIDs := make([]uint64, 0, len(splitIdxKeys))
-	for _, idxKey := range splitIdxKeys {
-		if isCtxDone(ctxWithTimeout) {
-			break
-		}
-
-		regionID, err := s.SplitRegion(idxKey, true)
-		if err != nil {
-			logutil.BgLogger().Warn("split table index region failed",
-				zap.String("table", e.tableInfo.Name.L),
-				zap.String("index", e.indexInfo.Name.L),
-				zap.Error(err))
-			continue
-		}
-		if regionID == 0 {
-			continue
-		}
-		regionIDs = append(regionIDs, regionID)
-
+	regionIDs, err := s.SplitRegions(context.Background(), splitIdxKeys, true)
+	if err != nil {
+		logutil.BgLogger().Warn("split table index region failed",
+			zap.String("table", e.tableInfo.Name.L),
+			zap.String("index", e.indexInfo.Name.L),
+			zap.Error(err))
 	}
 	e.splitRegions = len(regionIDs)
+	if e.splitRegions == 0 {
+		return nil
+	}
+
 	if !e.ctx.GetSessionVars().WaitSplitRegionFinish {
 		return nil
 	}
@@ -294,30 +284,17 @@ func (e *SplitTableRegionExec) splitTableRegion(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
-	regionIDs := make([]uint64, 0, len(splitKeys))
-	for _, key := range splitKeys {
-		failpoint.Inject("mockSplitRegionTimeout", func(val failpoint.Value) {
-			if val.(bool) {
-				time.Sleep(time.Second*1 + time.Millisecond*10)
-			}
-		})
-		if isCtxDone(ctxWithTimeout) {
-			break
-		}
-		regionID, err := s.SplitRegion(key, true)
-		if err != nil {
-			logutil.BgLogger().Warn("split table region failed",
-				zap.String("table", e.tableInfo.Name.L),
-				zap.Error(err))
-			continue
-		}
-		if regionID == 0 {
-			continue
-		}
-		regionIDs = append(regionIDs, regionID)
-
+	regionIDs, err := s.SplitRegions(ctxWithTimeout, splitKeys, true)
+	if err != nil {
+		logutil.BgLogger().Warn("split table region failed",
+			zap.String("table", e.tableInfo.Name.L),
+			zap.Error(err))
 	}
 	e.splitRegions = len(regionIDs)
+	if e.splitRegions == 0 {
+		return nil
+	}
+
 	if !e.ctx.GetSessionVars().WaitSplitRegionFinish {
 		return nil
 	}

go.mod

@@ -39,7 +39,7 @@ require (
 	github.com/pingcap/errors v0.11.4
 	github.com/pingcap/failpoint v0.0.0-20190512135322-30cc7431d99c
 	github.com/pingcap/goleveldb v0.0.0-20171020122428-b9ff6c35079e
-	github.com/pingcap/kvproto v0.0.0-20190724165112-ec9df5f208a7
+	github.com/pingcap/kvproto v0.0.0-20190821201150-798d27658fae
 	github.com/pingcap/log v0.0.0-20190307075452-bd41d9273596
 	github.com/pingcap/parser v0.0.0-20190902030720-275a827cf4e3
 	github.com/pingcap/pd v0.0.0-20190712044914-75a1f9f3062b

go.sum

@@ -162,8 +162,8 @@ github.com/pingcap/failpoint v0.0.0-20190512135322-30cc7431d99c/go.mod h1:DNS3Qg
 github.com/pingcap/goleveldb v0.0.0-20171020122428-b9ff6c35079e h1:P73/4dPCL96rGrobssy1nVy2VaVpNCuLpCbr+FEaTA8=
 github.com/pingcap/goleveldb v0.0.0-20171020122428-b9ff6c35079e/go.mod h1:O17XtbryoCJhkKGbT62+L2OlrniwqiGLSqrmdHCMzZw=
 github.com/pingcap/kvproto v0.0.0-20190516013202-4cf58ad90b6c/go.mod h1:QMdbTAXCHzzygQzqcG9uVUgU2fKeSN1GmfMiykdSzzY=
-github.com/pingcap/kvproto v0.0.0-20190724165112-ec9df5f208a7 h1:BMrtxXqQeZ9y27LN/V3PHA/tSyDWHK+90VLYaymrXQE=
-github.com/pingcap/kvproto v0.0.0-20190724165112-ec9df5f208a7/go.mod h1:QMdbTAXCHzzygQzqcG9uVUgU2fKeSN1GmfMiykdSzzY=
+github.com/pingcap/kvproto v0.0.0-20190821201150-798d27658fae h1:WR4d5ga8zXT+QDWYFzzyA+PJMMszR0kQxyYMh6dvHPg=
+github.com/pingcap/kvproto v0.0.0-20190821201150-798d27658fae/go.mod h1:QMdbTAXCHzzygQzqcG9uVUgU2fKeSN1GmfMiykdSzzY=
 github.com/pingcap/log v0.0.0-20190214045112-b37da76f67a7/go.mod h1:xsfkWVaFVV5B8e1K9seWfyJWFrIhbtUTAD8NV1Pq3+w=
 github.com/pingcap/log v0.0.0-20190307075452-bd41d9273596 h1:t2OQTpPJnrPDGlvA+3FwJptMTt6MEPdzK1Wt99oaefQ=
 github.com/pingcap/log v0.0.0-20190307075452-bd41d9273596/go.mod h1:WpHUKhNZ18v116SvGrmjkA9CBhYmuUTKL+p8JC9ANEw=

kv/kv.go

@@ -332,7 +332,7 @@ type Iterator interface {
 
 // SplitableStore is the kv store which supports split regions.
 type SplitableStore interface {
-	SplitRegion(splitKey Key, scatter bool) (regionID uint64, err error)
+	SplitRegions(ctx context.Context, splitKey [][]byte, scatter bool) (regionID []uint64, err error)
 	WaitScatterRegionFinish(regionID uint64, backOff int) error
 	CheckRegionInScattering(regionID uint64) (bool, error)
 }

store/mockstore/mocktikv/rpc.go

@@ -604,16 +604,25 @@ func (h *rpcHandler) handleKvRawScan(req *kvrpcpb.RawScanRequest) *kvrpcpb.RawSc
 }
 
 func (h *rpcHandler) handleSplitRegion(req *kvrpcpb.SplitRegionRequest) *kvrpcpb.SplitRegionResponse {
-	key := NewMvccKey(req.GetSplitKey())
-	region, _ := h.cluster.GetRegionByKey(key)
-	if bytes.Equal(region.GetStartKey(), key) {
-		return &kvrpcpb.SplitRegionResponse{}
-	}
-	newRegionID, newPeerIDs := h.cluster.AllocID(), h.cluster.AllocIDs(len(region.Peers))
-	newRegion := h.cluster.SplitRaw(region.GetId(), newRegionID, key, newPeerIDs, newPeerIDs[0])
-	// The mocktikv should return a deep copy of meta info to avoid data race
-	metaCloned := proto.Clone(newRegion.Meta)
-	return &kvrpcpb.SplitRegionResponse{Left: metaCloned.(*metapb.Region)}
+	keys := req.GetSplitKeys()
+	resp := &kvrpcpb.SplitRegionResponse{Regions: make([]*metapb.Region, 0, len(keys)+1)}
+	for i, key := range keys {
+		k := NewMvccKey(key)
+		region, _ := h.cluster.GetRegionByKey(k)
+		if bytes.Equal(region.GetStartKey(), key) {
+			continue
+		}
+		if i == 0 {
+			// Set the leftmost region.
+			resp.Regions = append(resp.Regions, region)
+		}
+		newRegionID, newPeerIDs := h.cluster.AllocID(), h.cluster.AllocIDs(len(region.Peers))
+		newRegion := h.cluster.SplitRaw(region.GetId(), newRegionID, k, newPeerIDs, newPeerIDs[0])
+		// The mocktikv should return a deep copy of meta info to avoid data race
+		metaCloned := proto.Clone(newRegion.Meta)
+		resp.Regions = append(resp.Regions, metaCloned.(*metapb.Region))
+	}
+	return resp
 }
 
 // RPCClient sends kv RPC calls to mock cluster. RPCClient mocks the behavior of

store/tikv/2pc.go

@@ -331,7 +331,7 @@ func (c *twoPhaseCommitter) doActionOnKeys(bo *Backoffer, action twoPhaseCommitA
 	if len(keys) == 0 {
 		return nil
 	}
-	groups, firstRegion, err := c.store.regionCache.GroupKeysByRegion(bo, keys)
+	groups, firstRegion, err := c.store.regionCache.GroupKeysByRegion(bo, keys, nil)
 	if err != nil {
 		return errors.Trace(err)
 	}

store/tikv/backoff.go

@@ -219,6 +219,7 @@ const (
 	deleteRangeOneRegionMaxBackoff = 100000
 	rawkvMaxBackoff                = 20000
 	splitRegionBackoff             = 20000
+	maxSplitRegionsBackoff         = 120000
 	scatterRegionBackoff           = 20000
 	waitScatterRegionFinishBackoff = 120000
 	locateRegionMaxBackoff         = 20000

store/tikv/rawkv.go

@@ -395,7 +395,7 @@ func (c *RawKVClient) sendReq(key []byte, req *tikvrpc.Request, reverse bool) (*
 }
 
 func (c *RawKVClient) sendBatchReq(bo *Backoffer, keys [][]byte, cmdType tikvrpc.CmdType) (*tikvrpc.Response, error) { // split the keys
-	groups, _, err := c.regionCache.GroupKeysByRegion(bo, keys)
+	groups, _, err := c.regionCache.GroupKeysByRegion(bo, keys, nil)
 	if err != nil {
 		return nil, errors.Trace(err)
 	}
@@ -544,7 +544,7 @@ func (c *RawKVClient) sendBatchPut(bo *Backoffer, keys, values [][]byte) error {
 	for i, key := range keys {
 		keyToValue[string(key)] = values[i]
 	}
-	groups, _, err := c.regionCache.GroupKeysByRegion(bo, keys)
+	groups, _, err := c.regionCache.GroupKeysByRegion(bo, keys, nil)
 	if err != nil {
 		return errors.Trace(err)
 	}

store/tikv/region_cache.go

@@ -473,7 +473,8 @@ func (c *RegionCache) LocateRegionByID(bo *Backoffer, regionID uint64) (*KeyLoca
 // GroupKeysByRegion separates keys into groups by their belonging Regions.
 // Specially it also returns the first key's region which may be used as the
 // 'PrimaryLockKey' and should be committed ahead of others.
-func (c *RegionCache) GroupKeysByRegion(bo *Backoffer, keys [][]byte) (map[RegionVerID][][]byte, RegionVerID, error) {
+// filter is used to filter some unwanted keys.
+func (c *RegionCache) GroupKeysByRegion(bo *Backoffer, keys [][]byte, filter func(key, regionStartKey []byte) bool) (map[RegionVerID][][]byte, RegionVerID, error) {
 	groups := make(map[RegionVerID][][]byte)
 	var first RegionVerID
 	var lastLoc *KeyLocation
@@ -484,6 +485,9 @@ func (c *RegionCache) GroupKeysByRegion(bo *Backoffer, keys [][]byte) (map[Regio
 			if err != nil {
 				return nil, first, errors.Trace(err)
 			}
+			if filter != nil && filter(k, lastLoc.StartKey) {
+				continue
+			}
 		}
 		id := lastLoc.Region
 		if i == 0 {

store/tikv/scan_test.go

@@ -91,12 +91,12 @@ func (s *testScanSuite) TestScan(c *C) {
 		c.Assert(err, IsNil)
 
 		if rowNum > 123 {
-			_, err = s.store.SplitRegion(encodeKey(s.prefix, s08d("key", 123)), false)
+			_, err = s.store.SplitRegions(context.Background(), [][]byte{encodeKey(s.prefix, s08d("key", 123))}, false)
 			c.Assert(err, IsNil)
 		}
 
 		if rowNum > 456 {
-			_, err = s.store.SplitRegion(encodeKey(s.prefix, s08d("key", 456)), false)
+			_, err = s.store.SplitRegions(context.Background(), [][]byte{encodeKey(s.prefix, s08d("key", 456))}, false)
 			c.Assert(err, IsNil)
 		}
 

store/tikv/snapshot.go

@@ -114,7 +114,7 @@ func (s *tikvSnapshot) BatchGet(ctx context.Context, keys []kv.Key) (map[string]
 }
 
 func (s *tikvSnapshot) batchGetKeysByRegions(bo *Backoffer, keys [][]byte, collectF func(k, v []byte)) error {
-	groups, _, err := s.store.regionCache.GroupKeysByRegion(bo, keys)
+	groups, _, err := s.store.regionCache.GroupKeysByRegion(bo, keys, nil)
 	if err != nil {
 		return errors.Trace(err)
 	}