tidb base 源码
tidb base 代码
文件路径：/planner/implementation/base.go
// Copyright 2018 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"
)
type baseImpl struct {
cost float64
plan plannercore.PhysicalPlan
}
func (impl *baseImpl) CalcCost(_ float64, children ...memo.Implementation) float64 {
impl.cost = 0
for _, child := range children {
impl.cost += child.GetCost()
}
return impl.cost
}
func (impl *baseImpl) SetCost(cost float64) {
impl.cost = cost
}
func (impl *baseImpl) GetCost() float64 {
return impl.cost
}
func (impl *baseImpl) GetPlan() plannercore.PhysicalPlan {
return impl.plan
}
func (impl *baseImpl) AttachChildren(children ...memo.Implementation) memo.Implementation {
childrenPlan := make([]plannercore.PhysicalPlan, len(children))
for i, child := range children {
childrenPlan[i] = child.GetPlan()
}
impl.plan.SetChildren(childrenPlan...)
return impl
}
func (*baseImpl) ScaleCostLimit(costLimit float64) float64 {
return costLimit
}
func (*baseImpl) GetCostLimit(costLimit float64, children ...memo.Implementation) float64 {
childrenCost := 0.0
for _, child := range children {
childrenCost += child.GetCost()
}
return costLimit - childrenCost
}
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