149b8184a6
Scheme info is generated when converting the initial logical plan tree to Group, so in exploration phase, we need to fill in the schema of newly built Group; stats info is generated in lazy style when it is needed during implementation phase.
40 lines
1.2 KiB
Go
40 lines
1.2 KiB
Go
// Copyright 2018 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 implementation
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import (
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"math"
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plannercore "github.com/pingcap/tidb/planner/core"
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"github.com/pingcap/tidb/planner/memo"
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)
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// SortImpl implementation of PhysicalSort.
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type SortImpl struct {
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baseImpl
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}
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// NewSortImpl creates a new sort Implementation.
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func NewSortImpl(sort *plannercore.PhysicalSort) *SortImpl {
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return &SortImpl{baseImpl{plan: sort}}
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}
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// CalcCost calculates the cost of the sort Implementation.
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func (impl *SortImpl) CalcCost(outCount float64, childCosts []float64, children ...*memo.Group) float64 {
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cnt := math.Min(children[0].Prop.Stats.RowCount, impl.plan.GetChildReqProps(0).ExpectedCnt)
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sort := impl.plan.(*plannercore.PhysicalSort)
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impl.cost = sort.GetCost(cnt) + childCosts[0]
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return impl.cost
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}
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