268 lines
7.4 KiB
Go
268 lines
7.4 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 (
|
|
"bytes"
|
|
"sort"
|
|
|
|
"github.com/juju/errors"
|
|
"github.com/pingcap/tidb/expression"
|
|
"github.com/pingcap/tidb/util/codec"
|
|
"github.com/pingcap/tidb/util/types"
|
|
)
|
|
|
|
type orderedRow struct {
|
|
key []byte
|
|
row Row
|
|
}
|
|
|
|
type orderedRows []orderedRow
|
|
|
|
// Len returns the number of rows.
|
|
func (e orderedRows) Len() int {
|
|
return len(e)
|
|
}
|
|
|
|
// Swap implements sort.Interface Swap interface.
|
|
func (e orderedRows) Swap(i, j int) {
|
|
e[i], e[j] = e[j], e[i]
|
|
}
|
|
|
|
// Less implements sort.Interface Less interface.
|
|
func (e orderedRows) Less(i, j int) bool {
|
|
return bytes.Compare(e[i].key, e[j].key) < 0
|
|
}
|
|
|
|
// IndexLookUpJoin fetches batches of data from outer executor and constructs ranges for inner executor.
|
|
type IndexLookUpJoin struct {
|
|
baseExecutor
|
|
|
|
innerExec DataReader
|
|
|
|
cursor int
|
|
resultRows []Row
|
|
outerRows orderedRows
|
|
innerRows orderedRows
|
|
innerDatums orderedRows // innerDatums are extracted by innerRows and innerJoinKeys
|
|
exhausted bool // exhausted means whether all data has been extracted
|
|
|
|
outerJoinKeys []*expression.Column
|
|
innerJoinKeys []*expression.Column
|
|
leftConditions expression.CNFExprs
|
|
rightConditions expression.CNFExprs
|
|
otherConditions expression.CNFExprs
|
|
defaultValues []types.Datum
|
|
outer bool
|
|
batchSize int
|
|
}
|
|
|
|
// Open implements the Executor Open interface.
|
|
func (e *IndexLookUpJoin) Open() error {
|
|
e.cursor = 0
|
|
e.exhausted = false
|
|
return errors.Trace(e.children[0].Open())
|
|
}
|
|
|
|
// Close implements the Executor Close interface.
|
|
func (e *IndexLookUpJoin) Close() error {
|
|
e.resultRows = nil
|
|
e.outerRows = nil
|
|
e.innerDatums = nil
|
|
return errors.Trace(e.children[0].Close())
|
|
}
|
|
|
|
// Next implements the Executor Next interface.
|
|
// We will fetch batches of row from outer executor, construct the inner datums and sort them.
|
|
// At the same time we will fetch the inner row by the inner datums and apply merge join.
|
|
func (e *IndexLookUpJoin) Next() (Row, error) {
|
|
for e.cursor == len(e.resultRows) {
|
|
if e.exhausted {
|
|
return nil, nil
|
|
}
|
|
e.outerRows = e.outerRows[:0]
|
|
e.innerRows = e.innerRows[:0]
|
|
e.resultRows = e.resultRows[:0]
|
|
e.innerDatums = e.innerDatums[:0]
|
|
for i := 0; i < e.batchSize; i++ {
|
|
outerRow, err := e.children[0].Next()
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
if outerRow == nil {
|
|
e.exhausted = true
|
|
break
|
|
}
|
|
match, err := expression.EvalBool(e.leftConditions, outerRow, e.ctx)
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
if match {
|
|
joinDatums := make([]types.Datum, 0, len(e.outerJoinKeys))
|
|
for i, col := range e.outerJoinKeys {
|
|
datum, err := col.Eval(outerRow)
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
innerDatum, err := datum.ConvertTo(e.ctx.GetSessionVars().StmtCtx, e.innerJoinKeys[i].GetType())
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
joinDatums = append(joinDatums, innerDatum)
|
|
}
|
|
joinOuterEncodeKey, err := codec.EncodeKey(nil, joinDatums...)
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
e.outerRows = append(e.outerRows, orderedRow{key: joinOuterEncodeKey, row: outerRow})
|
|
e.innerDatums = append(e.innerDatums, orderedRow{key: joinOuterEncodeKey, row: joinDatums})
|
|
} else if e.outer {
|
|
e.resultRows = append(e.resultRows, e.fillDefaultValues(outerRow))
|
|
}
|
|
}
|
|
sort.Sort(e.outerRows)
|
|
err := e.doJoin()
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
e.cursor = 0
|
|
}
|
|
row := e.resultRows[e.cursor]
|
|
e.cursor++
|
|
return row, nil
|
|
}
|
|
|
|
func (e *IndexLookUpJoin) fillDefaultValues(row Row) Row {
|
|
row = append(row, e.defaultValues...)
|
|
return row
|
|
}
|
|
|
|
func getUniqueDatums(rows orderedRows) [][]types.Datum {
|
|
datums := make([][]types.Datum, 0, rows.Len())
|
|
sort.Sort(rows)
|
|
for i := range rows {
|
|
if i > 0 && bytes.Equal(rows[i-1].key, rows[i].key) {
|
|
continue
|
|
}
|
|
datums = append(datums, rows[i].row)
|
|
}
|
|
return datums
|
|
}
|
|
|
|
// doJoin will join the outer rows and inner rows and store them to resultRows.
|
|
func (e *IndexLookUpJoin) doJoin() error {
|
|
err := e.innerExec.doRequestForDatums(getUniqueDatums(e.innerDatums), e.ctx.GoCtx())
|
|
if err != nil {
|
|
return errors.Trace(err)
|
|
}
|
|
defer e.innerExec.Close()
|
|
for {
|
|
innerRow, err := e.innerExec.Next()
|
|
if err != nil {
|
|
return errors.Trace(err)
|
|
}
|
|
if innerRow == nil {
|
|
break
|
|
}
|
|
match, err := expression.EvalBool(e.rightConditions, innerRow, e.ctx)
|
|
if err != nil {
|
|
return errors.Trace(err)
|
|
}
|
|
if !match {
|
|
continue
|
|
}
|
|
joinDatums := make([]types.Datum, 0, len(e.innerJoinKeys))
|
|
for _, col := range e.innerJoinKeys {
|
|
datum, _ := col.Eval(innerRow)
|
|
joinDatums = append(joinDatums, datum)
|
|
}
|
|
joinKey, err := codec.EncodeKey(nil, joinDatums...)
|
|
if err != nil {
|
|
return errors.Trace(err)
|
|
}
|
|
e.innerRows = append(e.innerRows, orderedRow{key: joinKey, row: innerRow})
|
|
}
|
|
sort.Sort(e.innerRows)
|
|
return e.doMergeJoin()
|
|
}
|
|
|
|
// getNextCursor will move cursor to the next datum that is different from the previous one and return it.
|
|
func getNextCursor(cursor int, rows orderedRows) int {
|
|
for {
|
|
cursor++
|
|
if cursor >= len(rows) {
|
|
break
|
|
}
|
|
c := bytes.Compare(rows[cursor].key, rows[cursor-1].key)
|
|
if c != 0 {
|
|
break
|
|
}
|
|
}
|
|
return cursor
|
|
}
|
|
|
|
// doMergeJoin joins the innerRows and outerRows which have been sorted before.
|
|
func (e *IndexLookUpJoin) doMergeJoin() error {
|
|
var outerCursor, innerCursor int
|
|
for outerCursor < len(e.outerRows) && innerCursor < len(e.innerRows) {
|
|
c := bytes.Compare(e.outerRows[outerCursor].key, e.innerRows[innerCursor].key)
|
|
if c == 0 {
|
|
outerBeginCursor := outerCursor
|
|
outerEndCursor := getNextCursor(outerCursor, e.outerRows)
|
|
innerBeginCursor := innerCursor
|
|
innerEndCursor := getNextCursor(innerCursor, e.innerRows)
|
|
for i := outerBeginCursor; i < outerEndCursor; i++ {
|
|
var outerMatch bool
|
|
outerRow := e.outerRows[i].row
|
|
for j := innerBeginCursor; j < innerEndCursor; j++ {
|
|
innerRow := e.innerRows[j].row
|
|
joinedRow := makeJoinRow(outerRow, innerRow)
|
|
match, err := expression.EvalBool(e.otherConditions, joinedRow, e.ctx)
|
|
if err != nil {
|
|
return errors.Trace(err)
|
|
}
|
|
if match {
|
|
outerMatch = true
|
|
e.resultRows = append(e.resultRows, joinedRow)
|
|
}
|
|
}
|
|
if e.outer && !outerMatch {
|
|
e.resultRows = append(e.resultRows, e.fillDefaultValues(outerRow))
|
|
}
|
|
}
|
|
outerCursor, innerCursor = outerEndCursor, innerEndCursor
|
|
} else if c < 0 {
|
|
// If outer smaller than inner, move and enlarge outer cursor
|
|
nextOuterCursor := getNextCursor(outerCursor, e.outerRows)
|
|
if !e.outer {
|
|
outerCursor = nextOuterCursor
|
|
} else {
|
|
for outerCursor < nextOuterCursor {
|
|
outerRow := e.outerRows[outerCursor].row
|
|
e.resultRows = append(e.resultRows, e.fillDefaultValues(outerRow))
|
|
outerCursor++
|
|
}
|
|
}
|
|
} else {
|
|
innerCursor = getNextCursor(innerCursor, e.outerRows)
|
|
}
|
|
}
|
|
for e.outer && outerCursor < len(e.outerRows) {
|
|
outerRow := e.outerRows[outerCursor].row
|
|
e.resultRows = append(e.resultRows, e.fillDefaultValues(outerRow))
|
|
outerCursor++
|
|
}
|
|
return nil
|
|
}
|