tidb join 源码
tidb join 代码
文件路径：/planner/implementation/join.go
// Copyright 2019 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 implementation
import (
plannercore "github.com/pingcap/tidb/planner/core"
"github.com/pingcap/tidb/planner/memo"
)
// HashJoinImpl is the implementation for PhysicalHashJoin.
type HashJoinImpl struct {
baseImpl
}
// CalcCost implements Implementation CalcCost interface.
func (impl *HashJoinImpl) CalcCost(_ float64, children ...memo.Implementation) float64 {
hashJoin := impl.plan.(*plannercore.PhysicalHashJoin)
// The children here are only used to calculate the cost.
hashJoin.SetChildren(children[0].GetPlan(), children[1].GetPlan())
selfCost := hashJoin.GetCost(children[0].GetPlan().StatsCount(), children[1].GetPlan().StatsCount(), false, 0, nil)
impl.cost = selfCost + children[0].GetCost() + children[1].GetCost()
return impl.cost
}
// AttachChildren implements Implementation AttachChildren interface.
func (impl *HashJoinImpl) AttachChildren(children ...memo.Implementation) memo.Implementation {
hashJoin := impl.plan.(*plannercore.PhysicalHashJoin)
hashJoin.SetChildren(children[0].GetPlan(), children[1].GetPlan())
return impl
}
// NewHashJoinImpl creates a new HashJoinImpl.
func NewHashJoinImpl(hashJoin *plannercore.PhysicalHashJoin) *HashJoinImpl {
return &HashJoinImpl{baseImpl{plan: hashJoin}}
}
// MergeJoinImpl is the implementation for PhysicalMergeJoin.
type MergeJoinImpl struct {
baseImpl
}
// CalcCost implements Implementation CalcCost interface.
func (impl *MergeJoinImpl) CalcCost(_ float64, children ...memo.Implementation) float64 {
mergeJoin := impl.plan.(*plannercore.PhysicalMergeJoin)
// The children here are only used to calculate the cost.
mergeJoin.SetChildren(children[0].GetPlan(), children[1].GetPlan())
selfCost := mergeJoin.GetCost(children[0].GetPlan().StatsCount(), children[1].GetPlan().StatsCount(), 0)
impl.cost = selfCost + children[0].GetCost() + children[1].GetCost()
return impl.cost
}
// AttachChildren implements Implementation AttachChildren interface.
func (impl *MergeJoinImpl) AttachChildren(children ...memo.Implementation) memo.Implementation {
mergeJoin := impl.plan.(*plannercore.PhysicalMergeJoin)
mergeJoin.SetChildren(children[0].GetPlan(), children[1].GetPlan())
return impl
}
// NewMergeJoinImpl creates a new MergeJoinImpl.
func NewMergeJoinImpl(mergeJoin *plannercore.PhysicalMergeJoin) *MergeJoinImpl {
return &MergeJoinImpl{baseImpl{plan: mergeJoin}}
}
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