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666 lines
18 KiB
666 lines
18 KiB
// 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 ranger
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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/pingcap/errors"
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"github.com/pingcap/parser/ast"
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"github.com/pingcap/parser/mysql"
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"github.com/pingcap/tidb/errno"
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"github.com/pingcap/tidb/expression"
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"github.com/pingcap/tidb/sessionctx"
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"github.com/pingcap/tidb/sessionctx/stmtctx"
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"github.com/pingcap/tidb/types"
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"github.com/pingcap/tidb/util/chunk"
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"github.com/pingcap/tidb/util/collate"
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"github.com/pingcap/tidb/util/dbterror"
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)
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// Error instances.
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var (
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ErrUnsupportedType = dbterror.ClassOptimizer.NewStd(errno.ErrUnsupportedType)
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)
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// RangeType is alias for int.
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type RangeType int
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// RangeType constants.
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const (
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IntRangeType RangeType = iota
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ColumnRangeType
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IndexRangeType
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)
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// Point is the end point of range interval.
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type point 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 point) 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 pointSorter struct {
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points []point
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err error
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sc *stmtctx.StatementContext
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}
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func (r *pointSorter) Len() int {
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return len(r.points)
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}
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func (r *pointSorter) 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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less, err := rangePointLess(r.sc, a, b)
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if err != nil {
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r.err = err
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}
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return less
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}
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func rangePointLess(sc *stmtctx.StatementContext, a, b point) (bool, error) {
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cmp, err := a.value.CompareDatum(sc, &b.value)
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if cmp != 0 {
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return cmp < 0, nil
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}
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return rangePointEqualValueLess(a, b), errors.Trace(err)
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}
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func rangePointEqualValueLess(a, b point) 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 !a.excl && !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 *pointSorter) 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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// fullRange is (-∞, +∞).
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var fullRange = []point{
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{start: true},
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{value: types.MaxValueDatum()},
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}
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// FullIntRange is used for table range. Since table range cannot accept MaxValueDatum as the max value.
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// So we need to set it to MaxInt64.
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func FullIntRange(isUnsigned bool) []*Range {
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if isUnsigned {
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return []*Range{{LowVal: []types.Datum{types.NewUintDatum(0)}, HighVal: []types.Datum{types.NewUintDatum(math.MaxUint64)}}}
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}
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return []*Range{{LowVal: []types.Datum{types.NewIntDatum(math.MinInt64)}, HighVal: []types.Datum{types.NewIntDatum(math.MaxInt64)}}}
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}
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// FullRange is [null, +∞) for Range.
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func FullRange() []*Range {
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return []*Range{{LowVal: []types.Datum{{}}, HighVal: []types.Datum{types.MaxValueDatum()}}}
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}
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// FullNotNullRange is (-∞, +∞) for Range.
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func FullNotNullRange() []*Range {
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return []*Range{{LowVal: []types.Datum{types.MinNotNullDatum()}, HighVal: []types.Datum{types.MaxValueDatum()}}}
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}
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// NullRange is [null, null] for Range.
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func NullRange() []*Range {
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return []*Range{{LowVal: []types.Datum{{}}, HighVal: []types.Datum{{}}}}
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}
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// builder is the range builder struct.
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type builder struct {
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err error
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sc *stmtctx.StatementContext
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ctx *sessionctx.Context
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}
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func (r *builder) build(expr expression.Expression) []point {
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switch x := expr.(type) {
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case *expression.Column:
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return r.buildFromColumn(x)
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case *expression.ScalarFunction:
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return r.buildFromScalarFunc(x)
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case *expression.Constant:
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return r.buildFromConstant(x)
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}
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return fullRange
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}
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func (r *builder) buildFromConstant(expr *expression.Constant) []point {
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dt, err := expr.Eval(chunk.Row{})
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if err != nil {
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r.err = err
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return nil
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}
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if dt.IsNull() {
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return nil
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}
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val, err := dt.ToBool(r.sc)
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if err != nil {
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r.err = err
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return nil
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}
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if val == 0 {
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return nil
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}
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return fullRange
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}
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func (r *builder) buildFromColumn(expr *expression.Column) []point {
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// column name expression is equivalent to column name is true.
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startPoint1 := point{value: types.MinNotNullDatum(), start: true}
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endPoint1 := point{excl: true}
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endPoint1.value.SetInt64(0)
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startPoint2 := point{excl: true, start: true}
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startPoint2.value.SetInt64(0)
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endPoint2 := point{value: types.MaxValueDatum()}
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return []point{startPoint1, endPoint1, startPoint2, endPoint2}
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}
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func (r *builder) buildFormBinOp(expr *expression.ScalarFunction) []point {
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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 (
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op string
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value types.Datum
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err error
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ft *types.FieldType
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)
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// refineValue refines the constant datum:
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// 1. for string type since we may eval the constant to another collation instead of its own collation.
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// 2. for year type since 2-digit year value need adjustment, see https://dev.mysql.com/doc/refman/5.6/en/year.html
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refineValue := func(col *expression.Column, value *types.Datum) (err error) {
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if col.RetType.EvalType() == types.ETString && value.Kind() == types.KindString {
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value.SetString(value.GetString(), col.RetType.Collate)
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}
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if col.GetType().Tp == mysql.TypeYear {
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*value, err = types.ConvertDatumToFloatYear(r.sc, *value)
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}
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return
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}
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if col, ok := expr.GetArgs()[0].(*expression.Column); ok {
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ft = col.RetType
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value, err = expr.GetArgs()[1].Eval(chunk.Row{})
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if err != nil {
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return nil
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}
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err = refineValue(col, &value)
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if err != nil {
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return nil
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}
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op = expr.FuncName.L
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} else {
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col, ok := expr.GetArgs()[1].(*expression.Column)
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if !ok {
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return nil
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}
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ft = col.RetType
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value, err = expr.GetArgs()[0].Eval(chunk.Row{})
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if err != nil {
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return nil
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}
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err = refineValue(col, &value)
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if err != nil {
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return nil
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}
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switch expr.FuncName.L {
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case ast.GE:
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op = ast.LE
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case ast.GT:
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op = ast.LT
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case ast.LT:
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op = ast.GT
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case ast.LE:
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op = ast.GE
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default:
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op = expr.FuncName.L
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}
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}
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if value.IsNull() {
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return nil
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}
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value, op, isValidRange := handleUnsignedIntCol(ft, value, op)
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if !isValidRange {
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return nil
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}
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switch op {
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case ast.EQ:
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startPoint := point{value: value, start: true}
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endPoint := point{value: value}
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return []point{startPoint, endPoint}
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case ast.NE:
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startPoint1 := point{value: types.MinNotNullDatum(), start: true}
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endPoint1 := point{value: value, excl: true}
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startPoint2 := point{value: value, start: true, excl: true}
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endPoint2 := point{value: types.MaxValueDatum()}
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return []point{startPoint1, endPoint1, startPoint2, endPoint2}
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case ast.LT:
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startPoint := point{value: types.MinNotNullDatum(), start: true}
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endPoint := point{value: value, excl: true}
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return []point{startPoint, endPoint}
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case ast.LE:
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startPoint := point{value: types.MinNotNullDatum(), start: true}
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endPoint := point{value: value}
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return []point{startPoint, endPoint}
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case ast.GT:
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startPoint := point{value: value, start: true, excl: true}
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endPoint := point{value: types.MaxValueDatum()}
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return []point{startPoint, endPoint}
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case ast.GE:
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startPoint := point{value: value, start: true}
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endPoint := point{value: types.MaxValueDatum()}
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return []point{startPoint, endPoint}
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}
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return nil
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}
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// handleUnsignedIntCol handles the case when unsigned column meets negative integer value.
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// The three returned values are: fixed constant value, fixed operator, and a boolean
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// which indicates whether the range is valid or not.
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func handleUnsignedIntCol(ft *types.FieldType, val types.Datum, op string) (types.Datum, string, bool) {
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isUnsigned := mysql.HasUnsignedFlag(ft.Flag)
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isIntegerType := mysql.IsIntegerType(ft.Tp)
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isNegativeInteger := (val.Kind() == types.KindInt64 && val.GetInt64() < 0)
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if !isUnsigned || !isIntegerType || !isNegativeInteger {
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return val, op, true
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}
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// If the operator is GT, GE or NE, the range should be [0, +inf].
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// Otherwise the value is out of valid range.
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if op == ast.GT || op == ast.GE || op == ast.NE {
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op = ast.GE
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val.SetUint64(0)
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return val, op, true
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}
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return val, op, false
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}
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func (r *builder) buildFromIsTrue(expr *expression.ScalarFunction, isNot int, keepNull bool) []point {
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if isNot == 1 {
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if keepNull {
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// Range is {[0, 0]}
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startPoint := point{start: true}
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startPoint.value.SetInt64(0)
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endPoint := point{}
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endPoint.value.SetInt64(0)
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return []point{startPoint, endPoint}
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}
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// NOT TRUE range is {[null null] [0, 0]}
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startPoint1 := point{start: true}
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endPoint1 := point{}
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startPoint2 := point{start: true}
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startPoint2.value.SetInt64(0)
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endPoint2 := point{}
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endPoint2.value.SetInt64(0)
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return []point{startPoint1, endPoint1, startPoint2, endPoint2}
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}
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// TRUE range is {[-inf 0) (0 +inf]}
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startPoint1 := point{value: types.MinNotNullDatum(), start: true}
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endPoint1 := point{excl: true}
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endPoint1.value.SetInt64(0)
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startPoint2 := point{excl: true, start: true}
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startPoint2.value.SetInt64(0)
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endPoint2 := point{value: types.MaxValueDatum()}
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return []point{startPoint1, endPoint1, startPoint2, endPoint2}
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}
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func (r *builder) buildFromIsFalse(expr *expression.ScalarFunction, isNot int) []point {
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if isNot == 1 {
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// NOT FALSE range is {[-inf, 0), (0, +inf], [null, null]}
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startPoint1 := point{start: true}
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endPoint1 := point{excl: true}
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endPoint1.value.SetInt64(0)
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startPoint2 := point{start: true, excl: true}
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startPoint2.value.SetInt64(0)
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endPoint2 := point{value: types.MaxValueDatum()}
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return []point{startPoint1, endPoint1, startPoint2, endPoint2}
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}
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// FALSE range is {[0, 0]}
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startPoint := point{start: true}
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startPoint.value.SetInt64(0)
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endPoint := point{}
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endPoint.value.SetInt64(0)
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return []point{startPoint, endPoint}
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}
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func (r *builder) buildFromIn(expr *expression.ScalarFunction) ([]point, bool) {
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list := expr.GetArgs()[1:]
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rangePoints := make([]point, 0, len(list)*2)
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hasNull := false
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colCollate := expr.GetArgs()[0].GetType().Collate
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for _, e := range list {
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v, ok := e.(*expression.Constant)
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if !ok {
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r.err = ErrUnsupportedType.GenWithStack("expr:%v is not constant", e)
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return fullRange, hasNull
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}
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dt, err := v.Eval(chunk.Row{})
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if err != nil {
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r.err = ErrUnsupportedType.GenWithStack("expr:%v is not evaluated", e)
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return fullRange, hasNull
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}
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if dt.IsNull() {
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hasNull = true
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continue
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}
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if dt.Kind() == types.KindString {
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dt.SetString(dt.GetString(), colCollate)
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}
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if expr.GetArgs()[0].GetType().Tp == mysql.TypeYear {
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dt, err = types.ConvertDatumToFloatYear(r.sc, dt)
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if err != nil {
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r.err = ErrUnsupportedType.GenWithStack("expr:%v is not converted to year", e)
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return fullRange, hasNull
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}
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}
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var startValue, endValue types.Datum
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dt.Copy(&startValue)
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dt.Copy(&endValue)
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startPoint := point{value: startValue, start: true}
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endPoint := point{value: endValue}
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rangePoints = append(rangePoints, startPoint, endPoint)
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}
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sorter := pointSorter{points: rangePoints, sc: r.sc}
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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 and remove duplicates
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curPos, frontPos := 0, 0
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for frontPos < len(rangePoints) {
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if rangePoints[curPos].start == rangePoints[frontPos].start {
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frontPos++
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} else {
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curPos++
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rangePoints[curPos] = rangePoints[frontPos]
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frontPos++
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}
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}
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if curPos > 0 {
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curPos++
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}
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return rangePoints[:curPos], hasNull
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}
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func (r *builder) newBuildFromPatternLike(expr *expression.ScalarFunction) []point {
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_, collation := expr.CharsetAndCollation(expr.GetCtx())
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if !collate.CompatibleCollate(expr.GetArgs()[0].GetType().Collate, collation) {
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return fullRange
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}
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pdt, err := expr.GetArgs()[1].(*expression.Constant).Eval(chunk.Row{})
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tpOfPattern := expr.GetArgs()[0].GetType()
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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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pattern, err := pdt.ToString()
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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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if pattern == "" {
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startPoint := point{value: types.NewStringDatum(""), start: true}
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endPoint := point{value: types.NewStringDatum("")}
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return []point{startPoint, endPoint}
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}
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lowValue := make([]byte, 0, len(pattern))
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edt, err := expr.GetArgs()[2].(*expression.Constant).Eval(chunk.Row{})
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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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escape := byte(edt.GetInt64())
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var exclude bool
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isExactMatch := true
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for i := 0; i < len(pattern); i++ {
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if pattern[i] == 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, 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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// Get the prefix.
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isExactMatch = false
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break
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} else if pattern[i] == '_' {
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// Get the prefix, but exclude the prefix.
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// e.g., "abc_x", the start point exclude "abc",
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// because the string length is more than 3.
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exclude = true
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isExactMatch = false
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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 []point{{value: types.MinNotNullDatum(), start: true}, {value: types.MaxValueDatum()}}
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}
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if isExactMatch {
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val := types.NewCollationStringDatum(string(lowValue), tpOfPattern.Collate, tpOfPattern.Flen)
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return []point{{value: val, start: true}, {value: val}}
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}
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startPoint := point{start: true, excl: exclude}
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startPoint.value.SetBytesAsString(lowValue, tpOfPattern.Collate, uint32(tpOfPattern.Flen))
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highValue := make([]byte, len(lowValue))
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copy(highValue, lowValue)
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endPoint := point{excl: true}
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for i := len(highValue) - 1; i >= 0; i-- {
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// Make the end point value more than the start point value,
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// and the length of the end point value is the same as the length of the start point value.
|
|
// e.g., the start point value is "abc", so the end point value is "abd".
|
|
highValue[i]++
|
|
if highValue[i] != 0 {
|
|
endPoint.value.SetBytesAsString(highValue, tpOfPattern.Collate, uint32(tpOfPattern.Flen))
|
|
break
|
|
}
|
|
// If highValue[i] is 255 and highValue[i]++ is 0, then the end point value is max value.
|
|
if i == 0 {
|
|
endPoint.value = types.MaxValueDatum()
|
|
}
|
|
}
|
|
return []point{startPoint, endPoint}
|
|
}
|
|
|
|
func (r *builder) buildFromNot(expr *expression.ScalarFunction) []point {
|
|
switch n := expr.FuncName.L; n {
|
|
case ast.IsTruthWithoutNull:
|
|
return r.buildFromIsTrue(expr, 1, false)
|
|
case ast.IsTruthWithNull:
|
|
return r.buildFromIsTrue(expr, 1, true)
|
|
case ast.IsFalsity:
|
|
return r.buildFromIsFalse(expr, 1)
|
|
case ast.In:
|
|
var (
|
|
isUnsignedIntCol bool
|
|
nonNegativePos int
|
|
)
|
|
rangePoints, hasNull := r.buildFromIn(expr)
|
|
if hasNull {
|
|
return nil
|
|
}
|
|
if x, ok := expr.GetArgs()[0].(*expression.Column); ok {
|
|
isUnsignedIntCol = mysql.HasUnsignedFlag(x.RetType.Flag) && mysql.IsIntegerType(x.RetType.Tp)
|
|
}
|
|
// negative ranges can be directly ignored for unsigned int columns.
|
|
if isUnsignedIntCol {
|
|
for nonNegativePos = 0; nonNegativePos < len(rangePoints); nonNegativePos += 2 {
|
|
if rangePoints[nonNegativePos].value.Kind() == types.KindUint64 || rangePoints[nonNegativePos].value.GetInt64() >= 0 {
|
|
break
|
|
}
|
|
}
|
|
rangePoints = rangePoints[nonNegativePos:]
|
|
}
|
|
retRangePoints := make([]point, 0, 2+len(rangePoints))
|
|
previousValue := types.Datum{}
|
|
for i := 0; i < len(rangePoints); i += 2 {
|
|
retRangePoints = append(retRangePoints, point{value: previousValue, start: true, excl: true})
|
|
retRangePoints = append(retRangePoints, point{value: rangePoints[i].value, excl: true})
|
|
previousValue = rangePoints[i].value
|
|
}
|
|
// Append the interval (last element, max value].
|
|
retRangePoints = append(retRangePoints, point{value: previousValue, start: true, excl: true})
|
|
retRangePoints = append(retRangePoints, point{value: types.MaxValueDatum()})
|
|
return retRangePoints
|
|
case ast.Like:
|
|
// Pattern not like is not supported.
|
|
r.err = ErrUnsupportedType.GenWithStack("NOT LIKE is not supported.")
|
|
return fullRange
|
|
case ast.IsNull:
|
|
startPoint := point{value: types.MinNotNullDatum(), start: true}
|
|
endPoint := point{value: types.MaxValueDatum()}
|
|
return []point{startPoint, endPoint}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (r *builder) buildFromScalarFunc(expr *expression.ScalarFunction) []point {
|
|
switch op := expr.FuncName.L; op {
|
|
case ast.GE, ast.GT, ast.LT, ast.LE, ast.EQ, ast.NE:
|
|
return r.buildFormBinOp(expr)
|
|
case ast.LogicAnd:
|
|
return r.intersection(r.build(expr.GetArgs()[0]), r.build(expr.GetArgs()[1]))
|
|
case ast.LogicOr:
|
|
return r.union(r.build(expr.GetArgs()[0]), r.build(expr.GetArgs()[1]))
|
|
case ast.IsTruthWithoutNull:
|
|
return r.buildFromIsTrue(expr, 0, false)
|
|
case ast.IsTruthWithNull:
|
|
return r.buildFromIsTrue(expr, 0, true)
|
|
case ast.IsFalsity:
|
|
return r.buildFromIsFalse(expr, 0)
|
|
case ast.In:
|
|
retPoints, _ := r.buildFromIn(expr)
|
|
return retPoints
|
|
case ast.Like:
|
|
return r.newBuildFromPatternLike(expr)
|
|
case ast.IsNull:
|
|
startPoint := point{start: true}
|
|
endPoint := point{}
|
|
return []point{startPoint, endPoint}
|
|
case ast.UnaryNot:
|
|
return r.buildFromNot(expr.GetArgs()[0].(*expression.ScalarFunction))
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (r *builder) intersection(a, b []point) []point {
|
|
return r.merge(a, b, false)
|
|
}
|
|
|
|
func (r *builder) union(a, b []point) []point {
|
|
return r.merge(a, b, true)
|
|
}
|
|
|
|
func (r *builder) mergeSorted(a, b []point) []point {
|
|
ret := make([]point, 0, len(a)+len(b))
|
|
i, j := 0, 0
|
|
for i < len(a) && j < len(b) {
|
|
less, err := rangePointLess(r.sc, a[i], b[j])
|
|
if err != nil {
|
|
r.err = err
|
|
return nil
|
|
}
|
|
if less {
|
|
ret = append(ret, a[i])
|
|
i++
|
|
} else {
|
|
ret = append(ret, b[j])
|
|
j++
|
|
}
|
|
}
|
|
if i < len(a) {
|
|
ret = append(ret, a[i:]...)
|
|
} else if j < len(b) {
|
|
ret = append(ret, b[j:]...)
|
|
}
|
|
return ret
|
|
}
|
|
|
|
func (r *builder) merge(a, b []point, union bool) []point {
|
|
mergedPoints := r.mergeSorted(a, b)
|
|
if r.err != nil {
|
|
return nil
|
|
}
|
|
|
|
var (
|
|
inRangeCount int
|
|
requiredInRangeCount int
|
|
)
|
|
if union {
|
|
requiredInRangeCount = 1
|
|
} else {
|
|
requiredInRangeCount = 2
|
|
}
|
|
curTail := 0
|
|
for _, val := range mergedPoints {
|
|
if val.start {
|
|
inRangeCount++
|
|
if inRangeCount == requiredInRangeCount {
|
|
// Just reached the required in range count, a new range started.
|
|
mergedPoints[curTail] = val
|
|
curTail++
|
|
}
|
|
} else {
|
|
if inRangeCount == requiredInRangeCount {
|
|
// Just about to leave the required in range count, the range is ended.
|
|
mergedPoints[curTail] = val
|
|
curTail++
|
|
}
|
|
inRangeCount--
|
|
}
|
|
}
|
|
return mergedPoints[:curTail]
|
|
}
|
|
|