コード例 #1
0
ファイル: aggregation_push_down.go プロジェクト: pingcap/tidb
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
}
コード例 #2
0
ファイル: aggregation_push_down.go プロジェクト: pingcap/tidb
// aggPushDown tries to push down aggregate functions to join paths.
func (a *aggPushDownSolver) aggPushDown(p LogicalPlan) {
	if agg, ok := p.(*Aggregation); ok {
		child := agg.GetChildByIndex(0)
		if join, ok1 := child.(*Join); ok1 && a.checkValidJoin(join) {
			if valid, leftAggFuncs, rightAggFuncs, leftGbyCols, rightGbyCols := a.splitAggFuncsAndGbyCols(agg, join); valid {
				var lChild, rChild LogicalPlan
				// If there exist count or sum functions in left join path, we can't push any
				// aggregate function into right join path.
				rightInvalid := a.checkAnyCountAndSum(leftAggFuncs)
				leftInvalid := a.checkAnyCountAndSum(rightAggFuncs)
				if rightInvalid {
					rChild = join.GetChildByIndex(1).(LogicalPlan)
				} else {
					rChild = a.tryToPushDownAgg(rightAggFuncs, rightGbyCols, join, 1)
				}
				if leftInvalid {
					lChild = join.GetChildByIndex(0).(LogicalPlan)
				} else {
					lChild = a.tryToPushDownAgg(leftAggFuncs, leftGbyCols, join, 0)
				}
				join.SetChildren(lChild, rChild)
				lChild.SetParents(join)
				rChild.SetParents(join)
				join.SetSchema(append(lChild.GetSchema().Clone(), rChild.GetSchema().Clone()...))
			}
		} else if proj, ok1 := child.(*Projection); ok1 {
			// TODO: This optimization is not always reasonable. We have not supported pushing projection to kv layer yet,
			// so we must do this optimization.
			for i, gbyItem := range agg.GroupByItems {
				agg.GroupByItems[i] = expression.ColumnSubstitute(gbyItem, proj.schema, proj.Exprs)
			}
			agg.collectGroupByColumns()
			for _, aggFunc := range agg.AggFuncs {
				newArgs := make([]expression.Expression, 0, len(aggFunc.GetArgs()))
				for _, arg := range aggFunc.GetArgs() {
					newArgs = append(newArgs, expression.ColumnSubstitute(arg, proj.schema, proj.Exprs))
				}
				aggFunc.SetArgs(newArgs)
			}
			projChild := proj.children[0]
			agg.SetChildren(projChild)
			projChild.SetParents(agg)
		} else if union, ok1 := child.(*Union); ok1 {
			pushedAgg := a.makeNewAgg(agg.AggFuncs, agg.groupByCols)
			newChildren := make([]Plan, 0, len(union.children))
			for _, child := range union.children {
				newChild := a.pushAggCrossUnion(pushedAgg, union.schema, child.(LogicalPlan))
				newChildren = append(newChildren, newChild)
				newChild.SetParents(union)
			}
			union.SetChildren(newChildren...)
			union.SetSchema(pushedAgg.schema)
		}
	}
	for _, child := range p.GetChildren() {
		a.aggPushDown(child.(LogicalPlan))
	}
}
コード例 #3
0
ファイル: predicate_push_down.go プロジェクト: pingcap/tidb
// PredicatePushDown implements LogicalPlan PredicatePushDown interface.
func (p *Projection) PredicatePushDown(predicates []expression.Expression) (ret []expression.Expression, retPlan LogicalPlan, err error) {
	retPlan = p
	var push []expression.Expression
	for _, cond := range predicates {
		canSubstitute := true
		extractedCols := expression.ExtractColumns(cond)
		for _, col := range extractedCols {
			id := p.GetSchema().GetIndex(col)
			if _, ok := p.Exprs[id].(*expression.ScalarFunction); ok {
				canSubstitute = false
				break
			}
		}
		if canSubstitute {
			push = append(push, expression.ColumnSubstitute(cond, p.GetSchema(), p.Exprs))
		} else {
			ret = append(ret, cond)
		}
	}
	child := p.GetChildByIndex(0).(LogicalPlan)
	restConds, _, err1 := child.PredicatePushDown(push)
	if err1 != nil {
		return nil, nil, errors.Trace(err1)
	}
	if len(restConds) > 0 {
		err1 = addSelection(p, child, restConds, p.allocator)
		if err1 != nil {
			return nil, nil, errors.Trace(err1)
		}
	}
	return
}
コード例 #4
0
ファイル: predicate_push_down.go プロジェクト: pingcap/tidb
// 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
}
コード例 #5
0
ファイル: predicate_push_down.go プロジェクト: pingcap/tidb
// PredicatePushDown implements LogicalPlan PredicatePushDown interface.
func (p *Aggregation) PredicatePushDown(predicates []expression.Expression) (ret []expression.Expression, retPlan LogicalPlan, err error) {
	retPlan = p
	var exprsOriginal []expression.Expression
	var condsToPush []expression.Expression
	for _, fun := range p.AggFuncs {
		exprsOriginal = append(exprsOriginal, fun.GetArgs()[0])
	}
	for _, cond := range predicates {
		switch cond.(type) {
		case *expression.Constant:
			condsToPush = append(condsToPush, cond)
			// Consider SQL list "select sum(b) from t group by a having 1=0". "1=0" is a constant predicate which should be
			// retained and pushed down at the same time. Because we will get a wrong query result that contains one column
			// with value 0 rather than an empty query result.
			ret = append(ret, cond)
		case *expression.ScalarFunction:
			extractedCols := expression.ExtractColumns(cond)
			ok := true
			for _, col := range extractedCols {
				if p.getGbyColIndex(col) == -1 {
					ok = false
					break
				}
			}
			if ok {
				newFunc := expression.ColumnSubstitute(cond.Clone(), p.GetSchema(), exprsOriginal)
				condsToPush = append(condsToPush, newFunc)
			} else {
				ret = append(ret, cond)
			}
		default:
			ret = append(ret, cond)
		}
	}
	p.baseLogicalPlan.PredicatePushDown(condsToPush)
	return
}