67 lines
2.4 KiB
Go
67 lines
2.4 KiB
Go
// Copyright 2023 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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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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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 core
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import "context"
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type pushDownSequenceSolver struct {
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}
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func (*pushDownSequenceSolver) name() string {
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return "push_down_sequence"
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}
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func (pdss *pushDownSequenceSolver) optimize(_ context.Context, lp LogicalPlan, _ *logicalOptimizeOp) (LogicalPlan, error) {
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return pdss.recursiveOptimize(nil, lp), nil
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}
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func (pdss *pushDownSequenceSolver) recursiveOptimize(pushedSequence *LogicalSequence, lp LogicalPlan) LogicalPlan {
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_, ok := lp.(*LogicalSequence)
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if !ok && pushedSequence == nil {
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newChildren := make([]LogicalPlan, 0, len(lp.Children()))
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for _, child := range lp.Children() {
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newChildren = append(newChildren, pdss.recursiveOptimize(nil, child))
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}
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lp.SetChildren(newChildren...)
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return lp
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}
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switch x := lp.(type) {
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case *LogicalSequence:
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if pushedSequence == nil {
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pushedSequence = LogicalSequence{}.Init(lp.SCtx(), lp.SelectBlockOffset())
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pushedSequence.SetChildren(lp.Children()...)
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return pdss.recursiveOptimize(pushedSequence, lp.Children()[len(lp.Children())-1])
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}
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childLen := len(x.children)
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mainQuery := x.children[childLen-1]
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allCTEs := make([]LogicalPlan, 0, childLen+len(pushedSequence.children)-2)
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allCTEs = append(allCTEs, pushedSequence.children[:len(pushedSequence.children)-1]...)
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allCTEs = append(allCTEs, x.children[:childLen-1]...)
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pushedSequence = LogicalSequence{}.Init(lp.SCtx(), lp.SelectBlockOffset())
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pushedSequence.SetChildren(append(allCTEs, mainQuery)...)
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return pdss.recursiveOptimize(pushedSequence, mainQuery)
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case *DataSource, *LogicalAggregation, *LogicalCTE:
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pushedSequence.SetChild(len(pushedSequence.children)-1, pdss.recursiveOptimize(nil, lp))
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return pushedSequence
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default:
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if len(lp.Children()) > 1 {
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pushedSequence.SetChild(len(pushedSequence.children)-1, lp)
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return pushedSequence
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}
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lp.SetChildren(pdss.recursiveOptimize(pushedSequence, lp.Children()[0]))
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return lp
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}
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}
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