Files
tidb/pkg/planner/core/logical_table_scan.go
2024-07-23 08:45:04 +00:00

158 lines
5.8 KiB
Go

// Copyright 2024 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,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package core
import (
"bytes"
"fmt"
"github.com/pingcap/tidb/pkg/expression"
"github.com/pingcap/tidb/pkg/parser/mysql"
"github.com/pingcap/tidb/pkg/planner/core/base"
"github.com/pingcap/tidb/pkg/planner/core/operator/logicalop"
"github.com/pingcap/tidb/pkg/planner/property"
"github.com/pingcap/tidb/pkg/planner/util"
"github.com/pingcap/tidb/pkg/util/plancodec"
"github.com/pingcap/tidb/pkg/util/ranger"
)
// LogicalTableScan is the logical table scan operator for TiKV.
type LogicalTableScan struct {
logicalop.LogicalSchemaProducer
Source *DataSource
HandleCols util.HandleCols
AccessConds expression.CNFExprs
Ranges []*ranger.Range
}
// Init initializes LogicalTableScan.
func (ts LogicalTableScan) Init(ctx base.PlanContext, offset int) *LogicalTableScan {
ts.BaseLogicalPlan = logicalop.NewBaseLogicalPlan(ctx, plancodec.TypeTableScan, &ts, offset)
return &ts
}
// *************************** start implementation of Plan interface ***************************
// ExplainInfo implements Plan interface.
func (ts *LogicalTableScan) ExplainInfo() string {
ectx := ts.SCtx().GetExprCtx().GetEvalCtx()
buffer := bytes.NewBufferString(ts.Source.ExplainInfo())
if ts.Source.HandleCols != nil {
fmt.Fprintf(buffer, ", pk col:%s", ts.Source.HandleCols.StringWithCtx(ectx, ts.SCtx().GetSessionVars().EnableRedactLog))
}
if len(ts.AccessConds) > 0 {
fmt.Fprintf(buffer, ", cond:%v", ts.AccessConds)
}
return buffer.String()
}
// *************************** end implementation of Plan interface ***************************
// *************************** start implementation of logicalPlan interface ***************************
// HashCode inherits BaseLogicalPlan.<0th> implementation.
// PredicatePushDown inherits BaseLogicalPlan.<1st> implementation.
// PruneColumns inherits BaseLogicalPlan.<2nd> implementation.
// FindBestTask inherits BaseLogicalPlan.LogicalPlan.<3rd> implementation.
// BuildKeyInfo implements base.LogicalPlan.<4th> interface.
func (ts *LogicalTableScan) BuildKeyInfo(selfSchema *expression.Schema, childSchema []*expression.Schema) {
ts.Source.BuildKeyInfo(selfSchema, childSchema)
}
// PushDownTopN inherits BaseLogicalPlan.<5th> implementation.
// DeriveTopN inherits BaseLogicalPlan.<6th> implementation.
// PredicateSimplification inherits BaseLogicalPlan.<7th> implementation.
// ConstantPropagation inherits BaseLogicalPlan.<8th> implementation.
// PullUpConstantPredicates inherits BaseLogicalPlan.<9th> implementation.
// RecursiveDeriveStats inherits BaseLogicalPlan.<10th> implementation.
// DeriveStats implements base.LogicalPlan.<11th> interface.
func (ts *LogicalTableScan) DeriveStats(_ []*property.StatsInfo, _ *expression.Schema, _ []*expression.Schema, _ [][]*expression.Column) (_ *property.StatsInfo, err error) {
ts.Source.initStats(nil)
// PushDownNot here can convert query 'not (a != 1)' to 'a = 1'.
exprCtx := ts.SCtx().GetExprCtx()
for i, expr := range ts.AccessConds {
// TODO The expressions may be shared by TableScan and several IndexScans, there would be redundant
// `PushDownNot` function call in multiple `DeriveStats` then.
ts.AccessConds[i] = expression.PushDownNot(exprCtx, expr)
}
ts.SetStats(ts.Source.deriveStatsByFilter(ts.AccessConds, nil))
// ts.Handle could be nil if PK is Handle, and PK column has been pruned.
// TODO: support clustered index.
if ts.HandleCols != nil {
// TODO: restrict mem usage of table ranges.
ts.Ranges, _, _, err = ranger.BuildTableRange(ts.AccessConds, ts.SCtx().GetRangerCtx(), ts.HandleCols.GetCol(0).RetType, 0)
} else {
isUnsigned := false
if ts.Source.TableInfo.PKIsHandle {
if pkColInfo := ts.Source.TableInfo.GetPkColInfo(); pkColInfo != nil {
isUnsigned = mysql.HasUnsignedFlag(pkColInfo.GetFlag())
}
}
ts.Ranges = ranger.FullIntRange(isUnsigned)
}
if err != nil {
return nil, err
}
return ts.StatsInfo(), nil
}
// ExtractColGroups inherits BaseLogicalPlan.<12th> implementation.
// PreparePossibleProperties implements base.LogicalPlan.<13th> interface.
func (ts *LogicalTableScan) PreparePossibleProperties(_ *expression.Schema, _ ...[][]*expression.Column) [][]*expression.Column {
if ts.HandleCols != nil {
cols := make([]*expression.Column, ts.HandleCols.NumCols())
for i := 0; i < ts.HandleCols.NumCols(); i++ {
cols[i] = ts.HandleCols.GetCol(i)
}
return [][]*expression.Column{cols}
}
return nil
}
// ExhaustPhysicalPlans inherits BaseLogicalPlan.<14th> implementation.
// ExtractCorrelatedCols inherits BaseLogicalPlan.LogicalPlan.<15th> implementation.
// MaxOneRow inherits BaseLogicalPlan.LogicalPlan.<16th> implementation.
// Children inherits BaseLogicalPlan.LogicalPlan.<17th> implementation.
// SetChildren inherits BaseLogicalPlan.LogicalPlan.<18th> implementation.
// SetChild inherits BaseLogicalPlan.LogicalPlan.<19th> implementation.
// RollBackTaskMap inherits BaseLogicalPlan.LogicalPlan.<20th> implementation.
// CanPushToCop inherits BaseLogicalPlan.LogicalPlan.<21st> implementation.
// ExtractFD inherits BaseLogicalPlan.LogicalPlan.<22nd> implementation.
// GetBaseLogicalPlan inherits BaseLogicalPlan.LogicalPlan.<23rd> implementation.
// ConvertOuterToInnerJoin inherits BaseLogicalPlan.LogicalPlan.<24th> implementation.
// *************************** end implementation of logicalPlan interface ***************************