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*: add unique key info into schema (pingcap#2376)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,210 @@ | ||
| // Copyright 2017 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, | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
|
|
||
| package plan | ||
|
|
||
| import ( | ||
| "github.com/pingcap/tidb/ast" | ||
| "github.com/pingcap/tidb/expression" | ||
| "github.com/pingcap/tidb/mysql" | ||
| ) | ||
|
|
||
| // A bijection exists between columns of an aggregation's schema and this aggregation's aggFuncs. | ||
| // Sometimes we need a schema made by arg of aggFuncs to convert a column in child's schema to a column in this aggregation's Schema. | ||
| func (p *Aggregation) buildSchemaByAggFuncs() expression.Schema { | ||
| schema := expression.NewSchema(make([]*expression.Column, 0, p.schema.Len())) | ||
| for _, fun := range p.AggFuncs { | ||
| if col, isCol := fun.GetArgs()[0].(*expression.Column); isCol && fun.GetName() == ast.AggFuncFirstRow { | ||
| schema.Append(col) | ||
| } else { | ||
| // If the arg is not a column, we add a column to occupy the position. | ||
| schema.Append(&expression.Column{ | ||
| Position: -1}) | ||
| } | ||
| } | ||
| return schema | ||
| } | ||
|
|
||
| func (p *Aggregation) buildKeyInfo() { | ||
| p.baseLogicalPlan.buildKeyInfo() | ||
| // dealing with p.AggFuncs | ||
| schemaByFuncs := p.buildSchemaByAggFuncs() | ||
| for _, key := range p.GetChildren()[0].GetSchema().Keys { | ||
| indices := schemaByFuncs.GetColumnsIndices(key) | ||
| if indices == nil { | ||
| continue | ||
| } | ||
| newKey := make([]*expression.Column, 0, len(key)) | ||
| for _, i := range indices { | ||
| newKey = append(newKey, p.schema.Columns[i]) | ||
| } | ||
| p.schema.Keys = append(p.schema.Keys, newKey) | ||
| } | ||
| // dealing with p.GroupbyCols | ||
| // This is only used for optimization and needn't to be pushed up, so only one is enough. | ||
| schemaByGroupby := expression.NewSchema(p.groupByCols) | ||
| for _, key := range p.GetChildren()[0].GetSchema().Keys { | ||
| indices := schemaByGroupby.GetColumnsIndices(key) | ||
| if indices == nil { | ||
| continue | ||
| } | ||
| newKey := make([]*expression.Column, 0, len(key)) | ||
| for _, i := range indices { | ||
| newKey = append(newKey, schemaByGroupby.Columns[i]) | ||
| } | ||
| p.schema.Keys = append(p.schema.Keys, newKey) | ||
| break | ||
| } | ||
| } | ||
|
|
||
| // A bijection exists between columns of a projection's schema and this projection's Exprs. | ||
| // Sometimes we need a schema made by expr of Exprs to convert a column in child's schema to a column in this projection's Schema. | ||
| func (p *Projection) buildSchemaByExprs() expression.Schema { | ||
| schema := expression.NewSchema(make([]*expression.Column, 0, p.schema.Len())) | ||
| for _, expr := range p.Exprs { | ||
| if col, isCol := expr.(*expression.Column); isCol { | ||
| schema.Append(col) | ||
| } else { | ||
| // If the expression is not a column, we add a column to occupy the position. | ||
| schema.Append(&expression.Column{ | ||
| Position: -1}) | ||
| } | ||
| } | ||
| return schema | ||
| } | ||
|
|
||
| func (p *Projection) buildKeyInfo() { | ||
| p.baseLogicalPlan.buildKeyInfo() | ||
| schema := p.buildSchemaByExprs() | ||
| for _, key := range p.GetChildren()[0].GetSchema().Keys { | ||
| indices := schema.GetColumnsIndices(key) | ||
| if indices == nil { | ||
| continue | ||
| } | ||
| newKey := make([]*expression.Column, 0, len(key)) | ||
| for _, i := range indices { | ||
| newKey = append(newKey, p.schema.Columns[i]) | ||
| } | ||
| p.schema.Keys = append(p.schema.Keys, newKey) | ||
| } | ||
| } | ||
|
|
||
| func (p *Trim) buildKeyInfo() { | ||
| p.baseLogicalPlan.buildKeyInfo() | ||
| for _, key := range p.children[0].GetSchema().Keys { | ||
| ok := true | ||
| newKey := make([]*expression.Column, 0, len(key)) | ||
| for _, col := range key { | ||
| pos := p.schema.GetColumnIndex(col) | ||
| if pos == -1 { | ||
| ok = false | ||
| break | ||
| } | ||
| newKey = append(newKey, p.schema.Columns[pos]) | ||
| } | ||
| if ok { | ||
| p.schema.Keys = append(p.schema.Keys, newKey) | ||
| } | ||
| } | ||
| } | ||
|
|
||
| func (p *Join) buildKeyInfo() { | ||
| p.baseLogicalPlan.buildKeyInfo() | ||
| switch p.JoinType { | ||
| case SemiJoin, SemiJoinWithAux: | ||
| p.schema.Keys = p.children[0].GetSchema().Clone().Keys | ||
| case InnerJoin, LeftOuterJoin, RightOuterJoin: | ||
| // If there is no equal conditions, then cartesian product can't be prevented and unique key information will destroy. | ||
| if len(p.EqualConditions) == 0 { | ||
| return | ||
| } | ||
| lOk := false | ||
| rOk := false | ||
| // Such as 'select * from t1 join t2 where t1.a = t2.a and t1.b = t2.b'. | ||
| // If one sides (a, b) is a unique key, then the unique key information is remained. | ||
| // But we don't consider this situation currently. | ||
| // Only key made by one column is considered now. | ||
| for _, expr := range p.EqualConditions { | ||
| ln := expr.GetArgs()[0].(*expression.Column) | ||
| rn := expr.GetArgs()[1].(*expression.Column) | ||
| for _, key := range p.children[0].GetSchema().Keys { | ||
| if len(key) == 1 && key[0].Equal(ln, p.ctx) { | ||
| lOk = true | ||
| break | ||
| } | ||
| } | ||
| for _, key := range p.children[1].GetSchema().Keys { | ||
| if len(key) == 1 && key[0].Equal(rn, p.ctx) { | ||
| rOk = true | ||
| break | ||
| } | ||
| } | ||
| } | ||
| // For inner join, if one side of one equal condition is unique key, | ||
| // another side's unique key information will all be reserved. | ||
| // If it's an outer join, NULL value will fill some position, which will destroy the unique key information. | ||
| if lOk && p.JoinType != LeftOuterJoin { | ||
| p.schema.Keys = append(p.schema.Keys, p.children[1].GetSchema().Keys...) | ||
| } | ||
| if rOk && p.JoinType != RightOuterJoin { | ||
| p.schema.Keys = append(p.schema.Keys, p.children[0].GetSchema().Keys...) | ||
| } | ||
| } | ||
| } | ||
|
|
||
| func (p *DataSource) buildKeyInfo() { | ||
| p.baseLogicalPlan.buildKeyInfo() | ||
| indices, _ := availableIndices(p.indexHints, p.tableInfo) | ||
| for _, idx := range indices { | ||
| if !idx.Unique { | ||
| continue | ||
| } | ||
| newKey := make([]*expression.Column, 0, len(idx.Columns)) | ||
| ok := true | ||
| for _, idxCol := range idx.Columns { | ||
| // The columns of this index should all occur in column schema. | ||
| // Since null value could be duplicate in unique key. So we check NotNull flag of every column. | ||
| find := false | ||
| for i, col := range p.schema.Columns { | ||
| if idxCol.Name.L == col.ColName.L { | ||
| if !mysql.HasNotNullFlag(p.Columns[i].Flag) { | ||
| break | ||
| } | ||
| newKey = append(newKey, p.schema.Columns[i]) | ||
| find = true | ||
| break | ||
| } | ||
| } | ||
| if !find { | ||
| ok = false | ||
| break | ||
| } | ||
| } | ||
| if ok { | ||
| p.schema.Keys = append(p.schema.Keys, newKey) | ||
| } | ||
| } | ||
| if p.tableInfo.PKIsHandle { | ||
| for i, col := range p.Columns { | ||
| if mysql.HasPriKeyFlag(col.Flag) { | ||
| p.schema.Keys = append(p.schema.Keys, []*expression.Column{p.schema.Columns[i]}) | ||
| break | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
|
||
| func (p *Apply) buildKeyInfo() { | ||
| p.baseLogicalPlan.buildKeyInfo() | ||
| p.schema.Keys = append(p.children[0].GetSchema().Clone().Keys, p.children[1].GetSchema().Clone().Keys...) | ||
| } |
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