506 lines
14 KiB
Go
506 lines
14 KiB
Go
// Copyright 2015 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package plan
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import (
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"fmt"
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"math"
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"sort"
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"github.com/juju/errors"
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"github.com/pingcap/tidb/ast"
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"github.com/pingcap/tidb/parser/opcode"
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"github.com/pingcap/tidb/util/types"
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)
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type rangePoint struct {
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value types.Datum
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excl bool // exclude
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start bool
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}
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func (rp rangePoint) String() string {
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val := rp.value.GetValue()
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if rp.value.Kind() == types.KindMinNotNull {
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val = "-inf"
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} else if rp.value.Kind() == types.KindMaxValue {
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val = "+inf"
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}
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if rp.start {
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symbol := "["
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if rp.excl {
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symbol = "("
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}
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return fmt.Sprintf("%s%v", symbol, val)
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}
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symbol := "]"
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if rp.excl {
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symbol = ")"
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}
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return fmt.Sprintf("%v%s", val, symbol)
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}
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type rangePointSorter struct {
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points []rangePoint
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err error
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}
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func (r *rangePointSorter) Len() int {
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return len(r.points)
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}
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func (r *rangePointSorter) Less(i, j int) bool {
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a := r.points[i]
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b := r.points[j]
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cmp, err := a.value.CompareDatum(b.value)
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if err != nil {
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r.err = err
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return true
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}
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if cmp == 0 {
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return r.equalValueLess(a, b)
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}
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return cmp < 0
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}
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func (r *rangePointSorter) equalValueLess(a, b rangePoint) bool {
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if a.start && b.start {
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return !a.excl && b.excl
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} else if a.start {
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return !b.excl
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} else if b.start {
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return a.excl || b.excl
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}
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return a.excl && !b.excl
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}
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func (r *rangePointSorter) Swap(i, j int) {
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r.points[i], r.points[j] = r.points[j], r.points[i]
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}
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type rangeBuilder struct {
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err error
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}
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func (r *rangeBuilder) build(expr ast.ExprNode) []rangePoint {
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switch x := expr.(type) {
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case *ast.BinaryOperationExpr:
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return r.buildFromBinop(x)
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case *ast.PatternInExpr:
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return r.buildFromIn(x)
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case *ast.ParenthesesExpr:
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return r.build(x.Expr)
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case *ast.BetweenExpr:
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return r.buildFromBetween(x)
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case *ast.IsNullExpr:
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return r.buildFromIsNull(x)
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case *ast.IsTruthExpr:
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return r.buildFromIsTruth(x)
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case *ast.PatternLikeExpr:
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rans := r.buildFromPatternLike(x)
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return rans
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case *ast.ColumnNameExpr:
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return r.buildFromColumnName(x)
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}
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return fullRange
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}
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func (r *rangeBuilder) buildFromBinop(x *ast.BinaryOperationExpr) []rangePoint {
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if x.Op == opcode.OrOr {
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return r.union(r.build(x.L), r.build(x.R))
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} else if x.Op == opcode.AndAnd {
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return r.intersection(r.build(x.L), r.build(x.R))
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}
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// This has been checked that the binary operation is comparison operation, and one of
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// the operand is column name expression.
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var value types.Datum
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var op opcode.Op
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if _, ok := x.L.(*ast.ValueExpr); ok {
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value = types.NewDatum(x.L.GetValue())
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switch x.Op {
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case opcode.GE:
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op = opcode.LE
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case opcode.GT:
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op = opcode.LT
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case opcode.LT:
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op = opcode.GT
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case opcode.LE:
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op = opcode.GE
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default:
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op = x.Op
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}
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} else {
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value = types.NewDatum(x.R.GetValue())
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op = x.Op
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}
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if value.Kind() == types.KindNull {
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return nil
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}
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switch op {
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case opcode.EQ:
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startPoint := rangePoint{value: value, start: true}
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endPoint := rangePoint{value: value}
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return []rangePoint{startPoint, endPoint}
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case opcode.NE:
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startPoint1 := rangePoint{value: types.MinNotNullDatum(), start: true}
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endPoint1 := rangePoint{value: value, excl: true}
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startPoint2 := rangePoint{value: value, start: true, excl: true}
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endPoint2 := rangePoint{value: types.MaxValueDatum()}
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return []rangePoint{startPoint1, endPoint1, startPoint2, endPoint2}
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case opcode.LT:
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startPoint := rangePoint{value: types.MinNotNullDatum(), start: true}
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endPoint := rangePoint{value: value, excl: true}
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return []rangePoint{startPoint, endPoint}
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case opcode.LE:
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startPoint := rangePoint{value: types.MinNotNullDatum(), start: true}
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endPoint := rangePoint{value: value}
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return []rangePoint{startPoint, endPoint}
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case opcode.GT:
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startPoint := rangePoint{value: value, start: true, excl: true}
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endPoint := rangePoint{value: types.MaxValueDatum()}
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return []rangePoint{startPoint, endPoint}
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case opcode.GE:
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startPoint := rangePoint{value: value, start: true}
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endPoint := rangePoint{value: types.MaxValueDatum()}
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return []rangePoint{startPoint, endPoint}
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}
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return nil
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}
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func (r *rangeBuilder) buildFromIn(x *ast.PatternInExpr) []rangePoint {
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if x.Not {
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r.err = ErrUnsupportedType.Gen("NOT IN is not supported")
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return fullRange
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}
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var rangePoints []rangePoint
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for _, v := range x.List {
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startPoint := rangePoint{value: types.NewDatum(v.GetValue()), start: true}
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endPoint := rangePoint{value: types.NewDatum(v.GetValue())}
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rangePoints = append(rangePoints, startPoint, endPoint)
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}
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sorter := rangePointSorter{points: rangePoints}
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sort.Sort(&sorter)
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if sorter.err != nil {
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r.err = sorter.err
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}
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// check duplicates
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hasDuplicate := false
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isStart := false
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for _, v := range rangePoints {
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if isStart == v.start {
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hasDuplicate = true
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break
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}
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isStart = v.start
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}
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if !hasDuplicate {
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return rangePoints
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}
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// remove duplicates
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distinctRangePoints := make([]rangePoint, 0, len(rangePoints))
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isStart = false
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for i := 0; i < len(rangePoints); i++ {
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current := rangePoints[i]
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if isStart == current.start {
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continue
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}
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distinctRangePoints = append(distinctRangePoints, current)
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isStart = current.start
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}
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return distinctRangePoints
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}
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func (r *rangeBuilder) buildFromBetween(x *ast.BetweenExpr) []rangePoint {
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if x.Not {
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binop1 := &ast.BinaryOperationExpr{Op: opcode.LT, L: x.Expr, R: x.Left}
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binop2 := &ast.BinaryOperationExpr{Op: opcode.GT, L: x.Expr, R: x.Right}
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range1 := r.buildFromBinop(binop1)
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range2 := r.buildFromBinop(binop2)
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return r.union(range1, range2)
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}
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binop1 := &ast.BinaryOperationExpr{Op: opcode.GE, L: x.Expr, R: x.Left}
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binop2 := &ast.BinaryOperationExpr{Op: opcode.LE, L: x.Expr, R: x.Right}
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range1 := r.buildFromBinop(binop1)
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range2 := r.buildFromBinop(binop2)
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return r.intersection(range1, range2)
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}
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func (r *rangeBuilder) buildFromIsNull(x *ast.IsNullExpr) []rangePoint {
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if x.Not {
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startPoint := rangePoint{value: types.MinNotNullDatum(), start: true}
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endPoint := rangePoint{value: types.MaxValueDatum()}
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return []rangePoint{startPoint, endPoint}
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}
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startPoint := rangePoint{start: true}
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endPoint := rangePoint{}
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return []rangePoint{startPoint, endPoint}
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}
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func (r *rangeBuilder) buildFromIsTruth(x *ast.IsTruthExpr) []rangePoint {
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if x.True != 0 {
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if x.Not {
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// NOT TRUE range is {[null null] [0, 0]}
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startPoint1 := rangePoint{start: true}
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endPoint1 := rangePoint{}
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startPoint2 := rangePoint{start: true}
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startPoint2.value.SetInt64(0)
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endPoint2 := rangePoint{}
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endPoint2.value.SetInt64(0)
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return []rangePoint{startPoint1, endPoint1, startPoint2, endPoint2}
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}
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// TRUE range is {[-inf 0) (0 +inf]}
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startPoint1 := rangePoint{value: types.MinNotNullDatum(), start: true}
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endPoint1 := rangePoint{excl: true}
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endPoint1.value.SetInt64(0)
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startPoint2 := rangePoint{excl: true, start: true}
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startPoint2.value.SetInt64(0)
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endPoint2 := rangePoint{value: types.MaxValueDatum()}
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return []rangePoint{startPoint1, endPoint1, startPoint2, endPoint2}
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}
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if x.Not {
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startPoint1 := rangePoint{start: true}
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endPoint1 := rangePoint{excl: true}
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endPoint1.value.SetInt64(0)
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startPoint2 := rangePoint{start: true, excl: true}
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startPoint2.value.SetInt64(0)
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endPoint2 := rangePoint{value: types.MaxValueDatum()}
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return []rangePoint{startPoint1, endPoint1, startPoint2, endPoint2}
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}
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startPoint := rangePoint{start: true}
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startPoint.value.SetInt64(0)
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endPoint := rangePoint{}
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endPoint.value.SetInt64(0)
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return []rangePoint{startPoint, endPoint}
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}
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func (r *rangeBuilder) buildFromPatternLike(x *ast.PatternLikeExpr) []rangePoint {
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if x.Not {
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// Pattern not like is not supported.
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r.err = ErrUnsupportedType.Gen("NOT LIKE is not supported.")
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return fullRange
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}
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pattern, err := types.ToString(x.Pattern.GetValue())
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if err != nil {
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r.err = errors.Trace(err)
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return fullRange
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}
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lowValue := make([]byte, 0, len(pattern))
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// unscape the pattern
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var exclude bool
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for i := 0; i < len(pattern); i++ {
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if pattern[i] == x.Escape {
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i++
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if i < len(pattern) {
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lowValue = append(lowValue, pattern[i])
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} else {
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lowValue = append(lowValue, x.Escape)
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}
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continue
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}
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if pattern[i] == '%' {
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break
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} else if pattern[i] == '_' {
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exclude = true
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break
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}
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lowValue = append(lowValue, pattern[i])
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}
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if len(lowValue) == 0 {
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return []rangePoint{{value: types.MinNotNullDatum(), start: true}, {value: types.MaxValueDatum()}}
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}
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startPoint := rangePoint{start: true, excl: exclude}
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startPoint.value.SetBytesAsString(lowValue)
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highValue := make([]byte, len(lowValue))
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copy(highValue, lowValue)
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endPoint := rangePoint{excl: true}
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for i := len(highValue) - 1; i >= 0; i-- {
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highValue[i]++
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if highValue[i] != 0 {
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endPoint.value.SetBytesAsString(highValue)
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break
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}
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if i == 0 {
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endPoint.value = types.MaxValueDatum()
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break
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}
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}
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ranges := make([]rangePoint, 2)
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ranges[0] = startPoint
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ranges[1] = endPoint
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return ranges
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}
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func (r *rangeBuilder) buildFromColumnName(x *ast.ColumnNameExpr) []rangePoint {
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// column name expression is equivalent to column name is true.
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startPoint1 := rangePoint{value: types.MinNotNullDatum(), start: true}
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endPoint1 := rangePoint{excl: true}
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endPoint1.value.SetInt64(0)
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startPoint2 := rangePoint{excl: true, start: true}
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startPoint2.value.SetInt64(0)
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endPoint2 := rangePoint{value: types.MaxValueDatum()}
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return []rangePoint{startPoint1, endPoint1, startPoint2, endPoint2}
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}
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func (r *rangeBuilder) intersection(a, b []rangePoint) []rangePoint {
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return r.merge(a, b, false)
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}
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func (r *rangeBuilder) union(a, b []rangePoint) []rangePoint {
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return r.merge(a, b, true)
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}
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func (r *rangeBuilder) merge(a, b []rangePoint, union bool) []rangePoint {
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sorter := rangePointSorter{points: append(a, b...)}
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sort.Sort(&sorter)
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if sorter.err != nil {
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r.err = sorter.err
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return nil
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}
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var (
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merged []rangePoint
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inRangeCount int
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requiredInRangeCount int
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)
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if union {
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requiredInRangeCount = 1
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} else {
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requiredInRangeCount = 2
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}
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for _, val := range sorter.points {
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if val.start {
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inRangeCount++
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if inRangeCount == requiredInRangeCount {
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// just reached the required in range count, a new range started.
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merged = append(merged, val)
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}
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} else {
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if inRangeCount == requiredInRangeCount {
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// just about to leave the required in range count, the range is ended.
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merged = append(merged, val)
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}
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inRangeCount--
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}
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}
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return merged
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}
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// buildIndexRanges build index ranges from range points.
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// Only the first column in the index is built, extra column ranges will be appended by
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// appendIndexRanges.
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func (r *rangeBuilder) buildIndexRanges(rangePoints []rangePoint) []*IndexRange {
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indexRanges := make([]*IndexRange, 0, len(rangePoints)/2)
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for i := 0; i < len(rangePoints); i += 2 {
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startPoint := rangePoints[i]
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endPoint := rangePoints[i+1]
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ir := &IndexRange{
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LowVal: []types.Datum{startPoint.value},
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LowExclude: startPoint.excl,
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HighVal: []types.Datum{endPoint.value},
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HighExclude: endPoint.excl,
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}
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indexRanges = append(indexRanges, ir)
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}
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return indexRanges
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}
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// appendIndexRanges appends additional column ranges for multi-column index.
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// The additional column ranges can only be appended to point ranges.
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// for example we have an index (a, b), if the condition is (a > 1 and b = 2)
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// then we can not build a conjunctive ranges for this index.
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func (r *rangeBuilder) appendIndexRanges(origin []*IndexRange, rangePoints []rangePoint) []*IndexRange {
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var newIndexRanges []*IndexRange
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for i := 0; i < len(origin); i++ {
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oRange := origin[i]
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if !oRange.IsPoint() {
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newIndexRanges = append(newIndexRanges, oRange)
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} else {
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newIndexRanges = append(newIndexRanges, r.appendIndexRange(oRange, rangePoints)...)
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}
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}
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return newIndexRanges
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}
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func (r *rangeBuilder) appendIndexRange(origin *IndexRange, rangePoints []rangePoint) []*IndexRange {
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newRanges := make([]*IndexRange, 0, len(rangePoints)/2)
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for i := 0; i < len(rangePoints); i += 2 {
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startPoint := rangePoints[i]
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lowVal := make([]types.Datum, len(origin.LowVal)+1)
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copy(lowVal, origin.LowVal)
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lowVal[len(origin.LowVal)] = startPoint.value
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endPoint := rangePoints[i+1]
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highVal := make([]types.Datum, len(origin.HighVal)+1)
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copy(highVal, origin.HighVal)
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highVal[len(origin.HighVal)] = endPoint.value
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ir := &IndexRange{
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LowVal: lowVal,
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LowExclude: startPoint.excl,
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HighVal: highVal,
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HighExclude: endPoint.excl,
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}
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newRanges = append(newRanges, ir)
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}
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return newRanges
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}
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func (r *rangeBuilder) buildTableRanges(rangePoints []rangePoint) []TableRange {
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tableRanges := make([]TableRange, 0, len(rangePoints)/2)
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for i := 0; i < len(rangePoints); i += 2 {
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startPoint := rangePoints[i]
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if startPoint.value.Kind() == types.KindNull || startPoint.value.Kind() == types.KindMinNotNull {
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startPoint.value.SetInt64(math.MinInt64)
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}
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startInt, err := types.ToInt64(startPoint.value.GetValue())
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if err != nil {
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r.err = errors.Trace(err)
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return tableRanges
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}
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startDatum := types.NewDatum(startInt)
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cmp, err := startDatum.CompareDatum(startPoint.value)
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if err != nil {
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r.err = errors.Trace(err)
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return tableRanges
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}
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if cmp < 0 || (cmp == 0 && startPoint.excl) {
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startInt++
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}
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endPoint := rangePoints[i+1]
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if endPoint.value.Kind() == types.KindNull {
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endPoint.value.SetInt64(math.MinInt64)
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} else if endPoint.value.Kind() == types.KindMaxValue {
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endPoint.value.SetInt64(math.MaxInt64)
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}
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endInt, err := types.ToInt64(endPoint.value.GetValue())
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if err != nil {
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r.err = errors.Trace(err)
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return tableRanges
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}
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endDatum := types.NewDatum(endInt)
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cmp, err = endDatum.CompareDatum(endPoint.value)
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if err != nil {
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r.err = errors.Trace(err)
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return tableRanges
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}
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if cmp > 0 || (cmp == 0 && endPoint.excl) {
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endInt--
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}
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if startInt > endInt {
|
|
continue
|
|
}
|
|
tableRanges = append(tableRanges, TableRange{LowVal: startInt, HighVal: endInt})
|
|
}
|
|
return tableRanges
|
|
}
|