mirror of
https://codeberg.org/forgejo/forgejo.git
synced 2024-12-15 11:58:11 -05:00
194 lines
4.6 KiB
Go
194 lines
4.6 KiB
Go
|
// Copyright 2015 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 plan
|
||
|
|
||
|
import (
|
||
|
"math"
|
||
|
|
||
|
"github.com/pingcap/tidb/ast"
|
||
|
"github.com/pingcap/tidb/model"
|
||
|
"github.com/pingcap/tidb/parser/opcode"
|
||
|
"github.com/pingcap/tidb/util/types"
|
||
|
)
|
||
|
|
||
|
// Refine tries to build index or table range.
|
||
|
func Refine(p Plan) error {
|
||
|
r := refiner{}
|
||
|
p.Accept(&r)
|
||
|
return r.err
|
||
|
}
|
||
|
|
||
|
type refiner struct {
|
||
|
err error
|
||
|
}
|
||
|
|
||
|
func (r *refiner) Enter(in Plan) (Plan, bool) {
|
||
|
return in, false
|
||
|
}
|
||
|
|
||
|
func (r *refiner) Leave(in Plan) (Plan, bool) {
|
||
|
switch x := in.(type) {
|
||
|
case *IndexScan:
|
||
|
r.buildIndexRange(x)
|
||
|
case *Limit:
|
||
|
x.SetLimit(0)
|
||
|
case *TableScan:
|
||
|
r.buildTableRange(x)
|
||
|
}
|
||
|
return in, r.err == nil
|
||
|
}
|
||
|
|
||
|
var fullRange = []rangePoint{
|
||
|
{start: true},
|
||
|
{value: types.MaxValueDatum()},
|
||
|
}
|
||
|
|
||
|
func (r *refiner) buildIndexRange(p *IndexScan) {
|
||
|
rb := rangeBuilder{}
|
||
|
if p.AccessEqualCount > 0 {
|
||
|
// Build ranges for equal access conditions.
|
||
|
point := rb.build(p.AccessConditions[0])
|
||
|
p.Ranges = rb.buildIndexRanges(point)
|
||
|
for i := 1; i < p.AccessEqualCount; i++ {
|
||
|
point = rb.build(p.AccessConditions[i])
|
||
|
p.Ranges = rb.appendIndexRanges(p.Ranges, point)
|
||
|
}
|
||
|
}
|
||
|
rangePoints := fullRange
|
||
|
// Build rangePoints for non-equal access condtions.
|
||
|
for i := p.AccessEqualCount; i < len(p.AccessConditions); i++ {
|
||
|
rangePoints = rb.intersection(rangePoints, rb.build(p.AccessConditions[i]))
|
||
|
}
|
||
|
if p.AccessEqualCount == 0 {
|
||
|
p.Ranges = rb.buildIndexRanges(rangePoints)
|
||
|
} else if p.AccessEqualCount < len(p.AccessConditions) {
|
||
|
p.Ranges = rb.appendIndexRanges(p.Ranges, rangePoints)
|
||
|
}
|
||
|
r.err = rb.err
|
||
|
return
|
||
|
}
|
||
|
|
||
|
func (r *refiner) buildTableRange(p *TableScan) {
|
||
|
if len(p.AccessConditions) == 0 {
|
||
|
p.Ranges = []TableRange{{math.MinInt64, math.MaxInt64}}
|
||
|
return
|
||
|
}
|
||
|
rb := rangeBuilder{}
|
||
|
rangePoints := fullRange
|
||
|
for _, cond := range p.AccessConditions {
|
||
|
rangePoints = rb.intersection(rangePoints, rb.build(cond))
|
||
|
}
|
||
|
p.Ranges = rb.buildTableRanges(rangePoints)
|
||
|
r.err = rb.err
|
||
|
}
|
||
|
|
||
|
// conditionChecker checks if this condition can be pushed to index plan.
|
||
|
type conditionChecker struct {
|
||
|
tableName model.CIStr
|
||
|
idx *model.IndexInfo
|
||
|
// the offset of the indexed column to be checked.
|
||
|
columnOffset int
|
||
|
pkName model.CIStr
|
||
|
}
|
||
|
|
||
|
func (c *conditionChecker) check(condition ast.ExprNode) bool {
|
||
|
switch x := condition.(type) {
|
||
|
case *ast.BinaryOperationExpr:
|
||
|
return c.checkBinaryOperation(x)
|
||
|
case *ast.BetweenExpr:
|
||
|
if ast.IsPreEvaluable(x.Left) && ast.IsPreEvaluable(x.Right) && c.checkColumnExpr(x.Expr) {
|
||
|
return true
|
||
|
}
|
||
|
case *ast.ColumnNameExpr:
|
||
|
return c.checkColumnExpr(x)
|
||
|
case *ast.IsNullExpr:
|
||
|
if c.checkColumnExpr(x.Expr) {
|
||
|
return true
|
||
|
}
|
||
|
case *ast.IsTruthExpr:
|
||
|
if c.checkColumnExpr(x.Expr) {
|
||
|
return true
|
||
|
}
|
||
|
case *ast.ParenthesesExpr:
|
||
|
return c.check(x.Expr)
|
||
|
case *ast.PatternInExpr:
|
||
|
if x.Sel != nil || x.Not {
|
||
|
return false
|
||
|
}
|
||
|
if !c.checkColumnExpr(x.Expr) {
|
||
|
return false
|
||
|
}
|
||
|
for _, val := range x.List {
|
||
|
if !ast.IsPreEvaluable(val) {
|
||
|
return false
|
||
|
}
|
||
|
}
|
||
|
return true
|
||
|
case *ast.PatternLikeExpr:
|
||
|
if x.Not {
|
||
|
return false
|
||
|
}
|
||
|
if !c.checkColumnExpr(x.Expr) {
|
||
|
return false
|
||
|
}
|
||
|
if !ast.IsPreEvaluable(x.Pattern) {
|
||
|
return false
|
||
|
}
|
||
|
patternVal := x.Pattern.GetValue()
|
||
|
if patternVal == nil {
|
||
|
return false
|
||
|
}
|
||
|
patternStr, err := types.ToString(patternVal)
|
||
|
if err != nil {
|
||
|
return false
|
||
|
}
|
||
|
firstChar := patternStr[0]
|
||
|
return firstChar != '%' && firstChar != '.'
|
||
|
}
|
||
|
return false
|
||
|
}
|
||
|
|
||
|
func (c *conditionChecker) checkBinaryOperation(b *ast.BinaryOperationExpr) bool {
|
||
|
switch b.Op {
|
||
|
case opcode.OrOr:
|
||
|
return c.check(b.L) && c.check(b.R)
|
||
|
case opcode.AndAnd:
|
||
|
return c.check(b.L) && c.check(b.R)
|
||
|
case opcode.EQ, opcode.NE, opcode.GE, opcode.GT, opcode.LE, opcode.LT:
|
||
|
if ast.IsPreEvaluable(b.L) {
|
||
|
return c.checkColumnExpr(b.R)
|
||
|
} else if ast.IsPreEvaluable(b.R) {
|
||
|
return c.checkColumnExpr(b.L)
|
||
|
}
|
||
|
}
|
||
|
return false
|
||
|
}
|
||
|
|
||
|
func (c *conditionChecker) checkColumnExpr(expr ast.ExprNode) bool {
|
||
|
cn, ok := expr.(*ast.ColumnNameExpr)
|
||
|
if !ok {
|
||
|
return false
|
||
|
}
|
||
|
if cn.Refer.Table.Name.L != c.tableName.L {
|
||
|
return false
|
||
|
}
|
||
|
if c.pkName.L != "" {
|
||
|
return c.pkName.L == cn.Refer.Column.Name.L
|
||
|
}
|
||
|
if c.idx != nil {
|
||
|
return cn.Refer.Column.Name.L == c.idx.Columns[c.columnOffset].Name.L
|
||
|
}
|
||
|
return true
|
||
|
}
|