func (a *aggPushDownSolver) pushAggCrossUnion(agg *Aggregation, unionSchema expression.Schema, unionChild LogicalPlan) LogicalPlan {
newAgg := &Aggregation{
AggFuncs: make([]expression.AggregationFunction, 0, len(agg.AggFuncs)),
GroupByItems: make([]expression.Expression, 0, len(agg.GroupByItems)),
baseLogicalPlan: newBaseLogicalPlan(Agg, a.alloc),
}
newAgg.SetSchema(agg.schema.Clone())
newAgg.correlated = agg.correlated
newAgg.initIDAndContext(a.ctx)
for _, aggFunc := range agg.AggFuncs {
newAggFunc := aggFunc.Clone()
newArgs := make([]expression.Expression, 0, len(newAggFunc.GetArgs()))
for _, arg := range newAggFunc.GetArgs() {
newArgs = append(newArgs, expression.ColumnSubstitute(arg, unionSchema, expression.Schema2Exprs(unionChild.GetSchema())))
}
newAggFunc.SetArgs(newArgs)
newAgg.AggFuncs = append(newAgg.AggFuncs, newAggFunc)
}
for _, gbyExpr := range agg.GroupByItems {
newExpr := expression.ColumnSubstitute(gbyExpr, unionSchema, expression.Schema2Exprs(unionChild.GetSchema()))
newAgg.GroupByItems = append(newAgg.GroupByItems, newExpr)
}
newAgg.collectGroupByColumns()
newAgg.SetChildren(unionChild)
unionChild.SetParents(newAgg)
return newAgg
}
func (a *aggPushDownSolver) makeNewAgg(aggFuncs []expression.AggregationFunction, gbyCols []*expression.Column) *Aggregation {
agg := &Aggregation{
GroupByItems: expression.Schema2Exprs(gbyCols),
baseLogicalPlan: newBaseLogicalPlan(Agg, a.alloc),
groupByCols: gbyCols,
}
agg.initIDAndContext(a.ctx)
var newAggFuncs []expression.AggregationFunction
schema := make(expression.Schema, 0, len(aggFuncs))
for _, aggFunc := range aggFuncs {
var newFuncs []expression.AggregationFunction
newFuncs, schema = a.decompose(aggFunc, schema, agg.GetID())
newAggFuncs = append(newAggFuncs, newFuncs...)
for _, arg := range aggFunc.GetArgs() {
agg.correlated = agg.correlated || arg.IsCorrelated()
}
}
for _, gbyCol := range gbyCols {
firstRow := expression.NewAggFunction(ast.AggFuncFirstRow, []expression.Expression{gbyCol.Clone()}, false)
newAggFuncs = append(newAggFuncs, firstRow)
schema = append(schema, gbyCol.Clone().(*expression.Column))
}
agg.AggFuncs = newAggFuncs
agg.SetSchema(schema)
return agg
}
// decompose splits an aggregate function to two parts: a final mode function and a partial mode function. Currently
// there are no differences between partial mode and complete mode, so we can confuse them.
func (a *aggPushDownSolver) decompose(aggFunc expression.AggregationFunction, schema expression.Schema, id string) ([]expression.AggregationFunction, expression.Schema) {
// Result is a slice because avg should be decomposed to sum and count. Currently we don't process this case.
result := []expression.AggregationFunction{aggFunc.Clone()}
for _, aggFunc := range result {
schema = append(schema, &expression.Column{
ColName: model.NewCIStr(fmt.Sprintf("join_agg_%d", len(schema))), // useless but for debug
FromID: id,
Position: len(schema),
RetType: aggFunc.GetType(),
})
}
aggFunc.SetArgs(expression.Schema2Exprs(schema[len(schema)-len(result):]))
aggFunc.SetMode(expression.FinalMode)
return result, schema
}
// PredicatePushDown implements LogicalPlan PredicatePushDown interface.
func (p *NewUnion) PredicatePushDown(predicates []expression.Expression) (ret []expression.Expression, err error) {
for _, proj := range p.Selects {
newExprs := make([]expression.Expression, 0, len(predicates))
for _, cond := range predicates {
newCond := columnSubstitute(cond.DeepCopy(), p.GetSchema(), expression.Schema2Exprs(proj.GetSchema()))
newExprs = append(newExprs, newCond)
}
retCond, err := proj.PredicatePushDown(newExprs)
if err != nil {
return nil, errors.Trace(err)
}
if len(retCond) != 0 {
addSelection(p, proj, retCond, p.allocator)
}
}
return
}
// PredicatePushDown implements LogicalPlan PredicatePushDown interface.
func (p *Union) PredicatePushDown(predicates []expression.Expression) (ret []expression.Expression, retPlan LogicalPlan, err error) {
retPlan = p
for _, proj := range p.children {
newExprs := make([]expression.Expression, 0, len(predicates))
for _, cond := range predicates {
newCond := expression.ColumnSubstitute(cond, p.GetSchema(), expression.Schema2Exprs(proj.GetSchema()))
newExprs = append(newExprs, newCond)
}
retCond, _, err := proj.(LogicalPlan).PredicatePushDown(newExprs)
if err != nil {
return nil, nil, errors.Trace(err)
}
if len(retCond) != 0 {
addSelection(p, proj.(LogicalPlan), retCond, p.allocator)
}
}
return
}
// predicatePushDown applies predicate push down to all kinds of plans, except aggregation and union.
func (b *planBuilder) predicatePushDown(p Plan, predicates []expression.Expression) (ret []expression.Expression, err error) {
switch v := p.(type) {
case *NewTableScan:
return predicates, nil
case *Selection:
conditions := v.Conditions
retConditions, err1 := b.predicatePushDown(p.GetChildByIndex(0), append(conditions, predicates...))
if err1 != nil {
return nil, errors.Trace(err1)
}
if len(retConditions) > 0 {
v.Conditions = retConditions
} else {
if len(p.GetParents()) == 0 {
return ret, nil
}
err1 = RemovePlan(p)
if err1 != nil {
return nil, errors.Trace(err1)
}
}
return
case *Join:
//TODO: add null rejecter.
var leftCond, rightCond []expression.Expression
leftPlan := v.GetChildByIndex(0)
rightPlan := v.GetChildByIndex(1)
equalCond, leftPushCond, rightPushCond, otherCond := extractOnCondition(predicates, leftPlan, rightPlan)
if v.JoinType == LeftOuterJoin {
rightCond = v.RightConditions
leftCond = leftPushCond
ret = append(expression.ScalarFuncs2Exprs(equalCond), otherCond...)
ret = append(ret, rightPushCond...)
} else if v.JoinType == RightOuterJoin {
leftCond = v.LeftConditions
rightCond = rightPushCond
ret = append(expression.ScalarFuncs2Exprs(equalCond), otherCond...)
ret = append(ret, leftPushCond...)
} else {
leftCond = append(v.LeftConditions, leftPushCond...)
rightCond = append(v.RightConditions, rightPushCond...)
}
leftRet, err1 := b.predicatePushDown(leftPlan, leftCond)
if err1 != nil {
return nil, errors.Trace(err1)
}
rightRet, err2 := b.predicatePushDown(rightPlan, rightCond)
if err2 != nil {
return nil, errors.Trace(err2)
}
if len(leftRet) > 0 {
err2 = b.addSelection(p, leftPlan, leftRet)
if err2 != nil {
return nil, errors.Trace(err2)
}
}
if len(rightRet) > 0 {
err2 = b.addSelection(p, rightPlan, rightRet)
if err2 != nil {
return nil, errors.Trace(err2)
}
}
if v.JoinType == InnerJoin {
v.EqualConditions = append(v.EqualConditions, equalCond...)
v.OtherConditions = append(v.OtherConditions, otherCond...)
}
return
case *Projection:
if len(v.GetChildren()) == 0 {
return predicates, nil
}
var push []expression.Expression
for _, cond := range predicates {
canSubstitute := true
extractedCols, _ := extractColumn(cond, nil, nil)
for _, col := range extractedCols {
id := v.GetSchema().GetIndex(col)
if _, ok := v.Exprs[id].(*expression.ScalarFunction); ok {
canSubstitute = false
break
}
}
if canSubstitute {
push = append(push, columnSubstitute(cond, v.GetSchema(), v.Exprs))
} else {
ret = append(ret, cond)
}
}
restConds, err1 := b.predicatePushDown(v.GetChildByIndex(0), push)
if err1 != nil {
return nil, errors.Trace(err1)
}
if len(restConds) > 0 {
err1 = b.addSelection(v, v.GetChildByIndex(0), restConds)
if err1 != nil {
return nil, errors.Trace(err1)
}
}
return
case *NewSort, *Limit, *Distinct:
rest, err1 := b.predicatePushDown(p.GetChildByIndex(0), predicates)
if err1 != nil {
return nil, errors.Trace(err1)
}
if len(rest) > 0 {
err1 = b.addSelection(p, p.GetChildByIndex(0), rest)
if err1 != nil {
return nil, errors.Trace(err1)
}
}
return
case *Union:
for _, proj := range v.Selects {
newExprs := make([]expression.Expression, 0, len(predicates))
for _, cond := range predicates {
newCond := columnSubstitute(cond.DeepCopy(), v.GetSchema(), expression.Schema2Exprs(proj.GetSchema()))
newExprs = append(newExprs, newCond)
}
retCond, err := b.predicatePushDown(proj, newExprs)
if err != nil {
return nil, errors.Trace(err)
}
if len(retCond) != 0 {
b.addSelection(v, proj, retCond)
}
}
return
//TODO: support aggregation, apply.
case *Aggregation, *Simple, *Apply:
return predicates, nil
default:
log.Warnf("Unknown Type %T in Predicate Pushdown", v)
return predicates, nil
}
}
