executor, mocktikv, util: add lookahead information passing for hash …

…join

executor/builder.go

@@ -1033,6 +1033,23 @@ func (b *executorBuilder) buildHashJoin(v *plannercore.PhysicalHashJoin) Executo
 			defaultValues = make([]types.Datum, e.innerExec.Schema().Len())
 		}
 	}
+
+	if e.joinType == plannercore.InnerJoin || e.joinType == plannercore.SemiJoin {
+		if outerReader, ok := e.outerExec.(*TableReaderExecutor); ok {
+			bfSize := uint64(e.innerEstCount) / 50
+			if bfSize < 10 {
+				bfSize = 10
+			}
+			e.bloomFilter = make([]uint64, bfSize)
+			outerReader.bloomFilter = e.bloomFilter
+
+			outerReader.joinKeyIdx = make([]int64, len(e.outerKeys))
+			for i := range e.innerKeys {
+				outerReader.joinKeyIdx[i] = int64(e.outerKeys[i].Index)
+			}
+		}
+	}
+
 	e.joiners = make([]joiner, e.concurrency)
 	for i := uint(0); i < e.concurrency; i++ {
 		e.joiners[i] = newJoiner(b.ctx, v.JoinType, v.InnerChildIdx == 0, defaultValues,

executor/join.go

@@ -16,6 +16,7 @@ package executor
 import (
 	"context"
 	"fmt"
+	"hash/fnv"
 	"sync"
 	"sync/atomic"
 
@@ -24,6 +25,8 @@ import (
 	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/expression"
 	plannercore "github.com/pingcap/tidb/planner/core"
+	"github.com/pingcap/tidb/tablecodec"
+	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/memory"
@@ -67,6 +70,11 @@ type HashJoinExec struct {
 	joinChkResourceCh  []chan *chunk.Chunk
 	joinResultCh       chan *hashjoinWorkerResult
 
+	// bloomFilter will be built from inner table and sent to outer table
+	// data source to "pre-filter" data.
+	// bloomFilter is initialized in executor builder.
+	bloomFilter []uint64
+
 	memTracker  *memory.Tracker // track memory usage.
 	prepared    bool
 	isOuterJoin bool
@@ -128,7 +136,7 @@ func (e *HashJoinExec) Close() error {
 
 // Open implements the Executor Open interface.
 func (e *HashJoinExec) Open(ctx context.Context) error {
-	if err := e.baseExecutor.Open(ctx); err != nil {
+	if err := e.innerExec.Open(ctx); err != nil {
 		return err
 	}
 
@@ -166,18 +174,11 @@ func (e *HashJoinExec) fetchOuterChunks(ctx context.Context) {
 			required := int(atomic.LoadInt64(&e.requiredRows))
 			outerResult.SetRequiredRows(required, e.maxChunkSize)
 		}
-		err := Next(ctx, e.outerExec, outerResult)
-		if err != nil {
-			e.joinResultCh <- &hashjoinWorkerResult{
-				err: err,
-			}
-			return
-		}
 		if !hasWaitedForInner {
-			if outerResult.NumRows() == 0 {
-				e.finished.Store(true)
-				return
-			}
+			// if outerResult.NumRows() == 0 {
+			// 	e.finished.Store(true)
+			// 	return
+			// }
 			jobFinished, innerErr := e.wait4Inner()
 			if innerErr != nil {
 				e.joinResultCh <- &hashjoinWorkerResult{
@@ -189,6 +190,13 @@ func (e *HashJoinExec) fetchOuterChunks(ctx context.Context) {
 			}
 			hasWaitedForInner = true
 		}
+		err := Next(ctx, e.outerExec, outerResult)
+		if err != nil {
+			e.joinResultCh <- &hashjoinWorkerResult{
+				err: err,
+			}
+			return
+		}
 
 		if outerResult.NumRows() == 0 {
 			return
@@ -487,6 +495,12 @@ func (e *HashJoinExec) fetchInnerAndBuildHashTable(ctx context.Context) {
 		e.innerFinished <- errors.Trace(err)
 		close(doneCh)
 	}
+
+	if err := e.outerExec.Open(ctx); err != nil {
+		e.innerFinished <- errors.Trace(err)
+		close(doneCh)
+	}
+
 	// Wait fetchInnerRows be finished.
 	// 1. if buildHashTableForList fails
 	// 2. if outerResult.NumRows() == 0, fetchOutChunks will not wait for inner.
@@ -520,6 +534,37 @@ func (e *HashJoinExec) buildHashTableForList(innerResultCh <-chan *chunk.Chunk)
 		if err != nil {
 			return err
 		}
+		if e.bloomFilter != nil {
+			err = e.putChunk2BloomFilter(chk, innerKeyColIdx, allTypes)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (e *HashJoinExec) putChunk2BloomFilter(chk *chunk.Chunk, innerKeyColIdx []int, allTypes []*types.FieldType) error {
+	// We use []uint64 as bit array for bloom filter, a single uint64 is a unit
+	bfUnitLen := uint64(64) // a uint64 has 64 bits
+	bfUnitsNum := uint64(len(e.bloomFilter))
+	bfBitLen := bfUnitLen * bfUnitsNum
+
+	numRows := chk.NumRows()
+	for i := 0; i <= numRows-1; i++ {
+		row := chk.GetRow(i)
+		hasher := fnv.New64a()
+		for _, colIdx := range innerKeyColIdx {
+			datum := row.GetDatum(colIdx, allTypes[colIdx])
+			encoded, err := tablecodec.EncodeValue(e.ctx.GetSessionVars().StmtCtx, nil, datum)
+			if err != nil {
+				return err
+			}
+			_, _ = hasher.Write(encoded)
+		}
+		hashSum := hasher.Sum64()
+		hashSum %= bfBitLen
+		e.bloomFilter[hashSum/bfUnitLen] |= 1 << (hashSum % bfUnitLen)
 	}
 	return nil
 }

executor/table_reader.go

@@ -16,6 +16,7 @@ package executor
 import (
 	"context"
 	"fmt"
+	"time"
 
 	"github.com/opentracing/opentracing-go"
 	"github.com/pingcap/parser/model"
@@ -72,6 +73,10 @@ type TableReaderExecutor struct {
 	memTracker       *memory.Tracker
 	selectResultHook // for testing
 
+	// bloomFilter is built in hash join executor before `Open` is called here.
+	bloomFilter []uint64
+	joinKeyIdx  []int64
+
 	keepOrder bool
 	desc      bool
 	streaming bool
@@ -100,6 +105,15 @@ func (e *TableReaderExecutor) Open(ctx context.Context) error {
 			return err
 		}
 	}
+
+	if e.bloomFilter != nil {
+		bfExec := &tipb.BloomFilter{
+			BitSet: e.bloomFilter,
+			ColIdx: e.joinKeyIdx,
+		}
+		e.dagPB.Executors = append(e.dagPB.Executors, &tipb.Executor{Tp: tipb.ExecType_TypeBloomFilter, BloomFilter: bfExec})
+	}
+
 	if e.runtimeStats != nil {
 		collExec := true
 		e.dagPB.CollectExecutionSummaries = &collExec
@@ -157,6 +171,7 @@ func (e *TableReaderExecutor) Next(ctx context.Context, req *chunk.Chunk) error
 		e.feedback.Invalidate()
 		return err
 	}
+	time.Sleep(time.Millisecond)
 	return nil
 }
 

store/mockstore/mocktikv/cop_handler_dag.go

@@ -34,6 +34,7 @@ import (
 	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/tablecodec"
 	"github.com/pingcap/tidb/types"
+	"github.com/pingcap/tidb/util/bloom"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/codec"
 	mockpkg "github.com/pingcap/tidb/util/mock"
@@ -157,6 +158,8 @@ func (h *rpcHandler) buildExec(ctx *dagContext, curr *tipb.Executor) (executor,
 		currExec, err = h.buildIndexScan(ctx, curr)
 	case tipb.ExecType_TypeSelection:
 		currExec, err = h.buildSelection(ctx, curr)
+	case tipb.ExecType_TypeBloomFilter:
+		currExec, err = h.buildBloomFilterExec(ctx, curr)
 	case tipb.ExecType_TypeAggregation:
 		currExec, err = h.buildHashAgg(ctx, curr)
 	case tipb.ExecType_TypeStreamAgg:
@@ -248,6 +251,18 @@ func (h *rpcHandler) buildIndexScan(ctx *dagContext, executor *tipb.Executor) (*
 	return e, nil
 }
 
+func (h *rpcHandler) buildBloomFilterExec(ctx *dagContext, executor *tipb.Executor) (*bloomFilterExec, error) {
+	relatedColumnOffsets := executor.BloomFilter.GetColIdx()
+	filter, _ := bloom.NewBloomFilterBySlice(executor.BloomFilter.GetBitSet())
+
+	return &bloomFilterExec{
+		bf:                filter,
+		relatedColOffsets: relatedColumnOffsets,
+		evalCtx:           ctx.evalCtx,
+		execDetail:        new(execDetail),
+	}, nil
+}
+
 func (h *rpcHandler) buildSelection(ctx *dagContext, executor *tipb.Executor) (*selectionExec, error) {
 	var err error
 	var relatedColOffsets []int

store/mockstore/mocktikv/executor.go

@@ -16,6 +16,7 @@ package mocktikv
 import (
 	"bytes"
 	"context"
+	"fmt"
 	"sort"
 	"time"
 
@@ -28,6 +29,7 @@ import (
 	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/tablecodec"
 	"github.com/pingcap/tidb/types"
+	"github.com/pingcap/tidb/util/bloom"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/codec"
 	"github.com/pingcap/tipb/go-tipb"
@@ -39,6 +41,7 @@ var (
 	_ executor = &selectionExec{}
 	_ executor = &limitExec{}
 	_ executor = &topNExec{}
+	_ executor = &bloomFilterExec{}
 )
 
 type execDetail struct {
@@ -720,3 +723,99 @@ func convertToExprs(sc *stmtctx.StatementContext, fieldTps []*types.FieldType, p
 	}
 	return exprs, nil
 }
+
+type bloomFilterExec struct {
+	bf                *bloom.BloomFilter
+	relatedColOffsets []int64
+	evalCtx           *evalContext
+	src               executor
+	execDetail        *execDetail
+	// row               []types.Datum
+	match float32
+	total float32
+}
+
+func (e *bloomFilterExec) ExecDetails() []*execDetail {
+	var suffix []*execDetail
+	if e.src != nil {
+		suffix = e.src.ExecDetails()
+	}
+	return append(suffix, e.execDetail)
+}
+
+func (e *bloomFilterExec) SetSrcExec(exec executor) {
+	e.src = exec
+}
+
+func (e *bloomFilterExec) GetSrcExec() executor {
+	return e.src
+}
+
+func (e *bloomFilterExec) ResetCounts() {
+	e.src.ResetCounts()
+}
+
+func (e *bloomFilterExec) Counts() []int64 {
+	return e.src.Counts()
+}
+
+func (e *bloomFilterExec) Cursor() ([]byte, bool) {
+	return e.src.Cursor()
+}
+
+func (e *bloomFilterExec) Next(ctx context.Context) (value [][]byte, err error) {
+	defer func(begin time.Time) {
+		e.execDetail.update(begin, value)
+	}(time.Now())
+	for {
+		value, err = e.src.Next(ctx)
+		if err != nil {
+			return nil, errors.Trace(err)
+		}
+		if value == nil {
+			fmt.Println("\033[0;32mMatched:", int(e.match), " Total:", int(e.total), " Match Rate:", e.match/e.total, "\033[0m")
+			return nil, nil
+		}
+
+		// if any of the attribute is null, continue
+		flag := checkIsNull(e.evalCtx, value, e.relatedColOffsets)
+		if flag {
+			continue
+		}
+
+		key := buildKey(value, e.relatedColOffsets)
+		e.total++
+		match := e.bf.Probe(key)
+		if match {
+			e.match++
+			return value, nil
+		}
+	}
+}
+
+// return true, if any one of the choice attributes value is null.
+// return false on all attributes value is not null.
+func checkIsNull(e *evalContext, value [][]byte, relatedColOffsets []int64) bool {
+	for _, offset := range relatedColOffsets {
+		// data, err := tablecodec.DecodeColumnValue(value[offset], e.fieldTps[offset], e.sc.TimeZone)
+		// if err != nil {
+		// 	return true, errors.Trace(err)
+		// }
+		// if data.IsNull() {
+		// 	return true, nil
+		// }
+		if value[offset][0] == codec.NilFlag {
+			return true
+		}
+	}
+	return false
+}
+
+// build the key for probe the bloom filter, by concatenate related col's value.
+func buildKey(value [][]byte, relatedColOffsets []int64) []byte {
+	var key []byte
+	for _, offset := range relatedColOffsets {
+		key = append(key, value[offset]...)
+	}
+	return key
+}