Files
tidb/executor/join_result_generators.go
2017-11-20 23:05:57 +08:00

397 lines
14 KiB
Go

// Copyright 2017 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
package executor
import (
"github.com/juju/errors"
"github.com/pingcap/tidb/context"
"github.com/pingcap/tidb/expression"
"github.com/pingcap/tidb/plan"
"github.com/pingcap/tidb/types"
)
var (
_ joinResultGenerator = &semiJoinResultGenerator{}
_ joinResultGenerator = &antiSemiJoinResultGenerator{}
_ joinResultGenerator = &leftOuterSemiJoinResultGenerator{}
_ joinResultGenerator = &antiLeftOuterSemiJoinResultGenerator{}
_ joinResultGenerator = &leftOuterJoinResultGenerator{}
_ joinResultGenerator = &rightOuterJoinResultGenerator{}
_ joinResultGenerator = &innerJoinResultGenerator{}
)
// joinResultGenerator is used to generate join results according the join type, see every implementor for detailed information.
type joinResultGenerator interface {
// emitMatchedInners should be called when key in outer row is equal to key in every inner row.
// Reutrn true if outer row can be joined with any input inner row.
emitMatchedInners(outer Row, inners []Row, resultBuffer []Row) ([]Row, bool, error)
// emitUnMatchedOuter should be called when outer row is not matched to any inner row.
emitUnMatchedOuter(outer Row, resultBuffer []Row) []Row
// emitUnMatchedOuters should be called when outer row is not matched to any inner row.
emitUnMatchedOuters(outers []Row, resultBuffer []Row) []Row
}
func newJoinResultGenerator(ctx context.Context, joinType plan.JoinType, outerIsRight bool, defaultInner Row, filter []expression.Expression) joinResultGenerator {
baseGenerator := baseJoinResultGenerator{ctx, filter, defaultInner, outerIsRight}
switch joinType {
case plan.SemiJoin:
return &semiJoinResultGenerator{baseGenerator}
case plan.AntiSemiJoin:
return &antiSemiJoinResultGenerator{baseGenerator}
case plan.LeftOuterSemiJoin:
return &leftOuterSemiJoinResultGenerator{baseGenerator}
case plan.AntiLeftOuterSemiJoin:
return &antiLeftOuterSemiJoinResultGenerator{baseGenerator}
case plan.LeftOuterJoin:
return &leftOuterJoinResultGenerator{baseGenerator}
case plan.RightOuterJoin:
return &rightOuterJoinResultGenerator{baseGenerator}
case plan.InnerJoin:
return &innerJoinResultGenerator{baseGenerator}
}
panic("unsupported join type in func newJoinResultGenerator()")
}
type baseJoinResultGenerator struct {
ctx context.Context
filter []expression.Expression
defaultInner Row
outerIsRight bool
}
// makeJoinRowToBuffer concatenates "lhs" and "rhs" to "buffer" and return that buffer.
// With the help of this function, we can make all of the joined rows to a consecutive
// memory buffer and explore the best cache performance.
func (outputer *baseJoinResultGenerator) makeJoinRowToBuffer(buffer []types.Datum, lhs, rhs Row) []types.Datum {
buffer = append(buffer, lhs...)
buffer = append(buffer, rhs...)
return buffer
}
// growResultBufferIfNecessary grows resultBuffer if necessary.
func (outputer *baseJoinResultGenerator) growResultBufferIfNecessary(resultBuffer []Row, numToAppend int) []Row {
length := len(resultBuffer)
if cap(resultBuffer)-length >= numToAppend {
return resultBuffer
}
newResultBuffer := make([]Row, length, length+numToAppend)
copy(newResultBuffer, resultBuffer)
return newResultBuffer
}
// filterResult filters resultBuffer according to filter.
func (outputer *baseJoinResultGenerator) filterResult(resultBuffer []Row, originLen int) ([]Row, bool, error) {
if outputer.filter == nil {
return resultBuffer, len(resultBuffer) > originLen, nil
}
curLen := originLen
for _, joinedRow := range resultBuffer[originLen:] {
matched, err := expression.EvalBool(outputer.filter, joinedRow, outputer.ctx)
if err != nil {
return nil, false, errors.Trace(err)
}
if matched {
resultBuffer[curLen] = joinedRow
curLen++
}
}
return resultBuffer[:curLen], curLen > originLen, nil
}
type semiJoinResultGenerator struct {
baseJoinResultGenerator
}
// emitMatchedInners implements joinResultGenerator interface.
func (outputer *semiJoinResultGenerator) emitMatchedInners(outer Row, inners []Row, resultBuffer []Row) ([]Row, bool, error) {
if len(inners) == 0 {
return resultBuffer, false, nil
}
if outputer.filter == nil {
return append(resultBuffer, outer), true, nil
}
buffer := make(Row, 0, len(inners[0])+len(outer))
for _, inner := range inners {
if outputer.outerIsRight {
buffer = outputer.makeJoinRowToBuffer(buffer[:0], inner, outer)
} else {
buffer = outputer.makeJoinRowToBuffer(buffer[:0], outer, inner)
}
matched, err := expression.EvalBool(outputer.filter, buffer, outputer.ctx)
if err != nil {
return resultBuffer, false, errors.Trace(err)
}
if matched {
return append(resultBuffer, outer), true, nil
}
}
return resultBuffer, false, nil
}
// emitUnMatchedOuter implements joinResultGenerator interface.
func (outputer *semiJoinResultGenerator) emitUnMatchedOuter(outer Row, resultBuffer []Row) []Row {
return resultBuffer
}
// emitUnMatchedOuters implements joinResultGenerator interface.
func (outputer *semiJoinResultGenerator) emitUnMatchedOuters(outers []Row, resultBuffer []Row) []Row {
return resultBuffer
}
type antiSemiJoinResultGenerator struct {
baseJoinResultGenerator
}
// emitMatchedInners implements joinResultGenerator interface.
func (outputer *antiSemiJoinResultGenerator) emitMatchedInners(outer Row, inners []Row, resultBuffer []Row) (_ []Row, matched bool, err error) {
if len(inners) == 0 {
return resultBuffer, false, nil
}
if outputer.filter == nil {
return resultBuffer, true, nil
}
buffer := make(Row, 0, len(outer)+len(inners[0]))
for _, inner := range inners {
if outputer.outerIsRight {
buffer = outputer.makeJoinRowToBuffer(buffer[:0], inner, outer)
} else {
buffer = outputer.makeJoinRowToBuffer(buffer[:0], outer, inner)
}
matched, err = expression.EvalBool(outputer.filter, buffer, outputer.ctx)
if err != nil {
return resultBuffer, false, errors.Trace(err)
}
if matched {
return resultBuffer, true, nil
}
}
return resultBuffer, false, nil
}
// emitUnMatchedOuter implements joinResultGenerator interface.
func (outputer *antiSemiJoinResultGenerator) emitUnMatchedOuter(outer Row, resultBuffer []Row) []Row {
return append(resultBuffer, outer)
}
// emitUnMatchedOuters implements joinResultGenerator interface.
func (outputer *antiSemiJoinResultGenerator) emitUnMatchedOuters(outers []Row, resultBuffer []Row) []Row {
for _, outer := range outers {
resultBuffer = append(resultBuffer, outer)
}
return resultBuffer
}
type leftOuterSemiJoinResultGenerator struct {
baseJoinResultGenerator
}
// emitMatchedInners implements joinResultGenerator interface.
func (outputer *leftOuterSemiJoinResultGenerator) emitMatchedInners(outer Row, inners []Row, resultBuffer []Row) ([]Row, bool, error) {
if len(inners) == 0 {
return resultBuffer, false, nil
}
if outputer.filter == nil {
joinedRow := append(outer, types.NewDatum(true))
return append(resultBuffer, joinedRow), true, nil
}
buffer := make(Row, 0, len(outer)+len(inners[0]))
for _, inner := range inners {
buffer = outputer.makeJoinRowToBuffer(buffer[:0], outer, inner)
matched, err := expression.EvalBool(outputer.filter, buffer, outputer.ctx)
if err != nil {
return resultBuffer, false, errors.Trace(err)
}
if matched {
buffer = append(buffer[:len(outer)], types.NewDatum(true))
return append(resultBuffer, buffer), true, nil
}
}
return resultBuffer, false, nil
}
// emitUnMatchedOuter implements joinResultGenerator interface.
func (outputer *leftOuterSemiJoinResultGenerator) emitUnMatchedOuter(outer Row, resultBuffer []Row) []Row {
outer = append(outer, types.NewDatum(false))
return append(resultBuffer, outer)
}
// emitUnMatchedOuters implements joinResultGenerator interface.
func (outputer *leftOuterSemiJoinResultGenerator) emitUnMatchedOuters(outers []Row, resultBuffer []Row) []Row {
for _, outer := range outers {
resultBuffer = append(resultBuffer, append(outer, types.NewDatum(false)))
}
return resultBuffer
}
type antiLeftOuterSemiJoinResultGenerator struct {
baseJoinResultGenerator
}
// emitMatchedInners implements joinResultGenerator interface.
func (outputer *antiLeftOuterSemiJoinResultGenerator) emitMatchedInners(outer Row, inners []Row, resultBuffer []Row) ([]Row, bool, error) {
if len(inners) == 0 {
return resultBuffer, false, nil
}
if outputer.filter == nil {
joinedRow := append(outer, types.NewDatum(false))
return append(resultBuffer, joinedRow), true, nil
}
buffer := make(Row, 0, len(outer)+len(inners[0]))
for _, inner := range inners {
buffer = outputer.makeJoinRowToBuffer(buffer[:0], outer, inner)
matched, err := expression.EvalBool(outputer.filter, buffer, outputer.ctx)
if err != nil {
return resultBuffer, false, errors.Trace(err)
}
if matched {
buffer = append(buffer[:len(outer)], types.NewDatum(false))
return append(resultBuffer, buffer), true, nil
}
}
return resultBuffer, false, nil
}
// emitUnMatchedOuter implements joinResultGenerator interface.
func (outputer *antiLeftOuterSemiJoinResultGenerator) emitUnMatchedOuter(outer Row, resultBuffer []Row) []Row {
outer = append(outer, types.NewDatum(true))
return append(resultBuffer, outer)
}
// emitUnMatchedOuters implements joinResultGenerator interface.
func (outputer *antiLeftOuterSemiJoinResultGenerator) emitUnMatchedOuters(outers []Row, resultBuffer []Row) []Row {
for _, outer := range outers {
resultBuffer = append(resultBuffer, append(outer, types.NewDatum(true)))
}
return resultBuffer
}
type leftOuterJoinResultGenerator struct {
baseJoinResultGenerator
}
// emitMatchedInners implements joinResultGenerator interface.
func (outputer *leftOuterJoinResultGenerator) emitMatchedInners(outer Row, inners []Row, resultBuffer []Row) ([]Row, bool, error) {
if len(inners) == 0 {
return resultBuffer, false, nil
}
resultBuffer = outputer.growResultBufferIfNecessary(resultBuffer, len(inners))
originLen := len(resultBuffer)
buffer := make([]types.Datum, 0, len(inners)*(len(outer)+len(inners[0])))
for _, inner := range inners {
buffer = outputer.makeJoinRowToBuffer(buffer[len(buffer):], outer, inner)
resultBuffer = append(resultBuffer, buffer)
}
return outputer.filterResult(resultBuffer, originLen)
}
// emitUnMatchedOuter implements joinResultGenerator interface.
func (outputer *leftOuterJoinResultGenerator) emitUnMatchedOuter(outer Row, resultBuffer []Row) []Row {
return append(resultBuffer, makeJoinRow(outer, outputer.defaultInner))
}
// emitUnMatchedOuters implements joinResultGenerator interface.
func (outputer *leftOuterJoinResultGenerator) emitUnMatchedOuters(outers []Row, resultBuffer []Row) []Row {
if len(outers) == 0 {
return resultBuffer
}
resultBuffer = outputer.growResultBufferIfNecessary(resultBuffer, len(outers))
buffer := make([]types.Datum, 0, len(outers)*(len(outers[0])+len(outputer.defaultInner)))
for _, outer := range outers {
buffer = outputer.makeJoinRowToBuffer(buffer[len(buffer):], outer, outputer.defaultInner)
resultBuffer = append(resultBuffer, buffer)
}
return resultBuffer
}
type rightOuterJoinResultGenerator struct {
baseJoinResultGenerator
}
// emitMatchedInners implements joinResultGenerator interface.
func (outputer *rightOuterJoinResultGenerator) emitMatchedInners(outer Row, inners []Row, resultBuffer []Row) ([]Row, bool, error) {
if len(inners) == 0 {
return resultBuffer, false, nil
}
resultBuffer = outputer.growResultBufferIfNecessary(resultBuffer, len(inners))
originLen := len(resultBuffer)
buffer := make([]types.Datum, 0, len(inners)*(len(outer)+len(inners[0])))
for _, inner := range inners {
buffer = outputer.makeJoinRowToBuffer(buffer[len(buffer):], inner, outer)
resultBuffer = append(resultBuffer, buffer)
}
return outputer.filterResult(resultBuffer, originLen)
}
// emitUnMatchedOuter implements joinResultGenerator interface.
func (outputer *rightOuterJoinResultGenerator) emitUnMatchedOuter(outer Row, resultBuffer []Row) []Row {
return append(resultBuffer, makeJoinRow(outputer.defaultInner, outer))
}
// emitUnMatchedOuters implements joinResultGenerator interface.
func (outputer *rightOuterJoinResultGenerator) emitUnMatchedOuters(outers []Row, resultBuffer []Row) []Row {
if len(outers) == 0 {
return resultBuffer
}
resultBuffer = outputer.growResultBufferIfNecessary(resultBuffer, len(outers))
buffer := make([]types.Datum, 0, len(outers)*(len(outers[0])+len(outputer.defaultInner)))
for _, outer := range outers {
buffer = outputer.makeJoinRowToBuffer(buffer[len(buffer):], outputer.defaultInner, outer)
resultBuffer = append(resultBuffer, buffer)
}
return resultBuffer
}
type innerJoinResultGenerator struct {
baseJoinResultGenerator
}
// emitMatchedInners implements joinResultGenerator interface.
func (outputer *innerJoinResultGenerator) emitMatchedInners(outer Row, inners []Row, resultBuffer []Row) ([]Row, bool, error) {
if len(inners) == 0 {
return resultBuffer, false, nil
}
resultBuffer = outputer.growResultBufferIfNecessary(resultBuffer, len(inners))
originLen := len(resultBuffer)
buffer := make([]types.Datum, 0, (len(outer)+len(inners[0]))*len(inners))
if outputer.outerIsRight {
for _, inner := range inners {
buffer = outputer.makeJoinRowToBuffer(buffer[len(buffer):], inner, outer)
resultBuffer = append(resultBuffer, buffer)
}
} else {
for _, inner := range inners {
buffer = outputer.makeJoinRowToBuffer(buffer[len(buffer):], outer, inner)
resultBuffer = append(resultBuffer, buffer)
}
}
return outputer.filterResult(resultBuffer, originLen)
}
// emitUnMatchedOuter implements joinResultGenerator interface.
func (outputer *innerJoinResultGenerator) emitUnMatchedOuter(_ Row, resultBuffer []Row) []Row {
return resultBuffer
}
// emitUnMatchedOuters implements joinResultGenerator interface.
func (outputer *innerJoinResultGenerator) emitUnMatchedOuters(_ []Row, resultBuffer []Row) []Row {
return resultBuffer
}