Optimize by collapsing trees into single SQL queries

graph/iterator/and_iterator_optimize.go

@@ -103,6 +103,7 @@ func (it *And) Optimize() (graph.Iterator, bool) {
 		newReplacement, hasOne := it.qs.OptimizeIterator(newAnd)
 		if hasOne {
 			newAnd.Close()
+			glog.V(3).Infoln(it.UID(), "became", newReplacement.UID(), "from quadstore")
 			return newReplacement, true
 		}
 	}
@@ -330,7 +331,7 @@ func materializeIts(its []graph.Iterator) []graph.Iterator {
 	out = append(out, its[0])
 	for _, it := range its[1:] {
 		stats := it.Stats()
-		if stats.Size*stats.NextCost < (stats.ContainsCost * (1 + (stats.Size / (allStats.Size + 1)))) {
+		if false && stats.Size*stats.NextCost < (stats.ContainsCost*(1+(stats.Size/(allStats.Size+1)))) {
 			if graph.Height(it, graph.Materialize) > 10 {
 				out = append(out, NewMaterialize(it))
 				continue

graph/iterator/hasa_iterator.go

@@ -105,6 +105,14 @@ func (it *HasA) Optimize() (graph.Iterator, bool) {
 			return it.primaryIt, true
 		}
 	}
+	// Ask the graph.QuadStore if we can be replaced. Often times, this is a great
+	// optimization opportunity (there's a fixed iterator underneath us, for
+	// example).
+	newReplacement, hasOne := it.qs.OptimizeIterator(it)
+	if hasOne {
+		it.Close()
+		return newReplacement, true
+	}
 	return it, false
 }
 

graph/iterator/not_iterator.go

@@ -140,6 +140,7 @@ func (it *Not) Optimize() (graph.Iterator, bool) {
 	if optimized {
 		it.primaryIt = optimizedPrimaryIt
 	}
+	it.primaryIt = NewMaterialize(it.primaryIt)
 	return it, false
 }
 

graph/sql/builder_iterator.go

@@ -46,6 +46,7 @@ func (td tableDir) String() string {
 type clause interface {
 	toSQL() (string, []string)
 	getTables() map[string]bool
+	size() int
 }
 
 type baseClause struct {
@@ -65,6 +66,8 @@ func (b baseClause) toSQL() (string, []string) {
 	return fmt.Sprintf("%s = ?", b.pair), []string{b.strTarget[0]}
 }
 
+func (b baseClause) size() int { return 1 }
+
 func (b baseClause) getTables() map[string]bool {
 	out := make(map[string]bool)
 	if b.pair.table != "" {
@@ -82,7 +85,27 @@ type joinClause struct {
 	op    clauseOp
 }
 
+func (jc joinClause) size() int {
+	size := 0
+	if jc.left != nil {
+		size += jc.left.size()
+	}
+	if jc.right != nil {
+		size += jc.right.size()
+	}
+	return size
+}
+
 func (jc joinClause) toSQL() (string, []string) {
+	if jc.left == nil {
+		if jc.right == nil {
+			return "", []string{}
+		}
+		return jc.right.toSQL()
+	}
+	if jc.right == nil {
+		return jc.left.toSQL()
+	}
 	l, lstr := jc.left.toSQL()
 	r, rstr := jc.right.toSQL()
 	lstr = append(lstr, rstr...)
@@ -93,14 +116,21 @@ func (jc joinClause) toSQL() (string, []string) {
 	case orClause:
 		op = "OR"
 	}
-	return fmt.Sprint("(%s %s %s)", l, op, r), lstr
+	return fmt.Sprintf("(%s %s %s)", l, op, r), lstr
 }
 
 func (jc joinClause) getTables() map[string]bool {
-	m := jc.left.getTables()
+	var m map[string]bool
+	if jc.left != nil {
+		m = jc.left.getTables()
+	} else {
+		m = make(map[string]bool)
+	}
+	if jc.right != nil {
 		for k, _ := range jc.right.getTables() {
 			m[k] = true
 		}
+	}
 	return m
 }
 
@@ -166,8 +196,14 @@ func (it *StatementIterator) buildQuery(contains bool, v graph.Value) (string, [
 		t = []string{fmt.Sprintf("%s.%s as __execd", it.tableName(), it.dir)}
 	}
 	for _, v := range it.tags {
+		if v.pair.table == "" {
+			v.pair.table = it.tableName()
+		}
 		t = append(t, fmt.Sprintf("%s as %s", v.pair, v.t))
 	}
+	for _, v := range it.tagger.Tags() {
+		t = append(t, fmt.Sprintf("%s as %s", tableDir{it.tableName(), it.dir}, v))
+	}
 	str += strings.Join(t, ", ")
 	str += " FROM "
 	t = []string{fmt.Sprintf("quads as %s", it.tableName())}
@@ -180,7 +216,7 @@ func (it *StatementIterator) buildQuery(contains bool, v graph.Value) (string, [
 	str += " WHERE "
 	var values []string
 	var s string
-	if it.stType != node {
+	if len(it.buildWhere) != 0 {
 		s, values = it.canonicalizeWhere()
 	}
 	if it.where != nil {
@@ -191,28 +227,31 @@ func (it *StatementIterator) buildQuery(contains bool, v graph.Value) (string, [
 		s += where
 		values = append(values, v2...)
 	}
-	str += s
+
 	if contains {
+		if s != "" {
+			s += " AND "
+		}
 		if it.stType == link {
 			q := v.(quad.Quad)
-			str += " AND "
 			t = []string{
 				fmt.Sprintf("%s.subject = ?", it.tableName()),
 				fmt.Sprintf("%s.predicate = ?", it.tableName()),
 				fmt.Sprintf("%s.object = ?", it.tableName()),
 				fmt.Sprintf("%s.label = ?", it.tableName()),
 			}
-			str += " " + strings.Join(t, " AND ") + " "
+			s += " " + strings.Join(t, " AND ") + " "
 			values = append(values, q.Subject)
 			values = append(values, q.Predicate)
 			values = append(values, q.Object)
 			values = append(values, q.Label)
 		} else {
-			str += fmt.Sprintf(" AND %s.%s = ? ", it.tableName(), it.dir)
+			s += fmt.Sprintf("%s.%s = ? ", it.tableName(), it.dir)
 			values = append(values, v.(string))
 		}
 
 	}
+	str += s
 	if it.stType == node {
 		str += " ORDER BY __execd "
 	}
@@ -220,6 +259,14 @@ func (it *StatementIterator) buildQuery(contains bool, v graph.Value) (string, [
 	for i := 1; i <= len(values); i++ {
 		str = strings.Replace(str, "?", fmt.Sprintf("$%d", i), 1)
 	}
+	glog.V(2).Infoln(str)
+	if glog.V(4) {
+		dstr := str
+		for i := 1; i <= len(values); i++ {
+			dstr = strings.Replace(dstr, fmt.Sprintf("$%d", i), fmt.Sprintf("'%s'", values[i-1]), 1)
+		}
+		glog.V(4).Infoln(dstr)
+	}
 	return str, values
 }
 
@@ -254,6 +301,7 @@ func (it *StatementIterator) Clone() graph.Iterator {
 		where:      it.where,
 		stType:     it.stType,
 		size:       it.size,
+		dir:        it.dir,
 	}
 	copy(it.tags, m.tags)
 	m.tagger.CopyFrom(it)
@@ -364,6 +412,12 @@ func (it *StatementIterator) Contains(v graph.Value) bool {
 		ivalues = append(ivalues, v)
 	}
 	it.cursor, err = it.qs.db.Query(q, ivalues...)
+	if err != nil {
+		glog.Errorf("Couldn't make query: %v", err)
+		it.err = err
+		it.cursor.Close()
+		return false
+	}
 	it.cols, err = it.cursor.Columns()
 	if err != nil {
 		glog.Errorf("Couldn't get columns")
@@ -414,10 +468,17 @@ func (it *StatementIterator) Size() (int64, bool) {
 		return it.size, true
 	}
 	if it.stType == node {
-		return it.qs.Size(), true
+		if it.where == nil {
+			return it.qs.Size() / int64(len(it.buildWhere)+1), true
+		}
+		return it.qs.Size() / int64(it.where.size()+len(it.buildWhere)+1), true
 	}
 	b := it.buildWhere[0]
+	if len(b.strTarget) > 0 {
 		it.size = it.qs.sizeForIterator(false, b.pair.dir, b.strTarget[0])
+	} else {
+		return it.qs.Size(), false
+	}
 	return it.size, true
 }
 
@@ -425,7 +486,7 @@ func (it *StatementIterator) Describe() graph.Description {
 	size, _ := it.Size()
 	return graph.Description{
 		UID:  it.UID(),
-		Name: "SQL_QUERY",
+		Name: fmt.Sprintf("SQL_QUERY: %#v", it),
 		Type: it.Type(),
 		Size: size,
 	}
@@ -451,7 +512,7 @@ func (it *StatementIterator) makeCursor() {
 	}
 	cursor, err := it.qs.db.Query(q, ivalues...)
 	if err != nil {
-		glog.Errorln("Couldn't get cursor from SQL database: %v", err)
+		glog.Errorf("Couldn't get cursor from SQL database: %v", err)
 		cursor = nil
 	}
 	it.cursor = cursor
@@ -542,7 +603,7 @@ func (it *StatementIterator) Next() bool {
 		return graph.NextLogOut(it, nil, false)
 	}
 	it.buildResult(0)
-	return graph.NextLogOut(it, it.result, true)
+	return graph.NextLogOut(it, it.Result(), true)
 }
 
 func (it *StatementIterator) scan() ([]string, error) {

graph/sql/optimizers.go

@@ -0,0 +1,287 @@
+// Copyright 2015 The Cayley Authors. All rights reserved.
+//
+// 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,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sql
+
+import (
+	"errors"
+
+	"github.com/barakmich/glog"
+	"github.com/google/cayley/graph"
+	"github.com/google/cayley/graph/iterator"
+	"github.com/google/cayley/quad"
+)
+
+func intersect(a *StatementIterator, b *StatementIterator) (*StatementIterator, error) {
+	if a.stType != b.stType {
+		return nil, errors.New("Cannot combine SQL iterators of two different types")
+	}
+	min := a.size
+	if b.size < a.size {
+		min = b.size
+	}
+	var where clause
+	if a.where == nil {
+		if b.where == nil {
+			where = nil
+		}
+		where = b.where
+	} else {
+		if b.where == nil {
+			where = a.where
+		}
+		where = joinClause{a.where, b.where, andClause}
+	}
+	out := &StatementIterator{
+		uid:        iterator.NextUID(),
+		qs:         a.qs,
+		buildWhere: append(a.buildWhere, b.buildWhere...),
+		tags:       append(a.tags, b.tags...),
+		where:      where,
+		stType:     a.stType,
+		size:       min,
+		dir:        a.dir,
+	}
+	out.tagger.CopyFrom(a)
+	out.tagger.CopyFrom(b)
+	if out.stType == node {
+		out.buildWhere = append(out.buildWhere, baseClause{
+			pair:   tableDir{"", a.dir},
+			target: tableDir{b.tableName(), b.dir},
+		})
+	}
+	return out, nil
+}
+
+func hasa(a *StatementIterator, d quad.Direction) (*StatementIterator, error) {
+	if a.stType != link {
+		return nil, errors.New("Can't take the HASA of a link SQL iterator")
+	}
+
+	out := &StatementIterator{
+		uid:    iterator.NextUID(),
+		qs:     a.qs,
+		stType: node,
+		dir:    d,
+	}
+	where := a.where
+	for _, w := range a.buildWhere {
+		w.pair.table = out.tableName()
+		wherenew := joinClause{where, w, andClause}
+		where = wherenew
+	}
+	out.where = where
+	//out := &StatementIterator{
+	//uid:        iterator.NextUID(),
+	//qs:         a.qs,
+	//stType:     node,
+	//dir:        d,
+	//buildWhere: a.buildWhere,
+	//where:      a.where,
+	//size:       -1,
+	//}
+	for k, v := range a.tagger.Fixed() {
+		out.tagger.AddFixed(k, v)
+	}
+	var tags []tag
+	for _, t := range a.tagger.Tags() {
+		tags = append(tags, tag{
+			pair: tableDir{
+				table: out.tableName(),
+				dir:   quad.Any,
+			},
+			t: t,
+		})
+	}
+	out.tags = append(tags, a.tags...)
+	return out, nil
+}
+
+func linksto(a *StatementIterator, d quad.Direction) (*StatementIterator, error) {
+	if a.stType != node {
+		return nil, errors.New("Can't take the LINKSTO of a node SQL iterator")
+	}
+	out := &StatementIterator{
+		uid:    iterator.NextUID(),
+		qs:     a.qs,
+		stType: link,
+		dir:    d,
+		size:   -1,
+	}
+	where := a.where
+	for _, w := range a.buildWhere {
+		w.pair.table = a.tableName()
+		wherenew := joinClause{where, w, andClause}
+		where = wherenew
+	}
+
+	out.where = where
+	out.buildWhere = []baseClause{
+		baseClause{
+			pair: tableDir{
+				dir: d,
+			},
+			target: tableDir{
+				table: a.tableName(),
+				dir:   a.dir,
+			},
+		},
+	}
+	var tags []tag
+	for _, t := range a.tagger.Tags() {
+		tags = append(tags, tag{
+			pair: tableDir{
+				table: a.tableName(),
+				dir:   a.dir,
+			},
+			t: t,
+		})
+	}
+	for k, v := range a.tagger.Fixed() {
+		out.tagger.AddFixed(k, v)
+	}
+	for _, t := range a.tags {
+		if t.pair.table == "" {
+			t.pair.table = a.tableName()
+		}
+		tags = append(tags, t)
+	}
+	out.tags = tags
+	return out, nil
+}
+
+func (qs *QuadStore) OptimizeIterator(it graph.Iterator) (graph.Iterator, bool) {
+	switch it.Type() {
+	case graph.LinksTo:
+		return qs.optimizeLinksTo(it.(*iterator.LinksTo))
+	case graph.HasA:
+		return qs.optimizeHasA(it.(*iterator.HasA))
+	case graph.And:
+		return qs.optimizeAnd(it.(*iterator.And))
+	}
+	return it, false
+}
+
+func (qs *QuadStore) optimizeLinksTo(it *iterator.LinksTo) (graph.Iterator, bool) {
+	subs := it.SubIterators()
+	if len(subs) != 1 {
+		return it, false
+	}
+	primary := subs[0]
+	switch primary.Type() {
+	case graph.Fixed:
+		size, _ := primary.Size()
+		if size == 1 {
+			if !graph.Next(primary) {
+				panic("unexpected size during optimize")
+			}
+			val := primary.Result()
+			newIt := qs.QuadIterator(it.Direction(), val)
+			nt := newIt.Tagger()
+			nt.CopyFrom(it)
+			for _, tag := range primary.Tagger().Tags() {
+				nt.AddFixed(tag, val)
+			}
+			it.Close()
+			return newIt, true
+		}
+	case sqlBuilderType:
+		newit, err := linksto(primary.(*StatementIterator), it.Direction())
+		if err != nil {
+			glog.Errorln(err)
+			return it, false
+		}
+		newit.Tagger().CopyFrom(it)
+		return newit, true
+	case graph.All:
+		newit := &StatementIterator{
+			uid:    iterator.NextUID(),
+			qs:     qs,
+			stType: link,
+			size:   qs.Size(),
+		}
+		for _, t := range primary.Tagger().Tags() {
+			newit.tags = append(newit.tags, tag{
+				pair: tableDir{"", it.Direction()},
+				t:    t,
+			})
+		}
+		for k, v := range primary.Tagger().Fixed() {
+			newit.tagger.AddFixed(k, v)
+		}
+		newit.tagger.CopyFrom(it)
+
+		return newit, true
+	}
+	return it, false
+}
+
+func (qs *QuadStore) optimizeAnd(it *iterator.And) (graph.Iterator, bool) {
+	subs := it.SubIterators()
+	var unusedIts []graph.Iterator
+	var newit *StatementIterator
+	newit = nil
+	changed := false
+	var err error
+
+	for _, it := range subs {
+		if it.Type() == sqlBuilderType {
+			if newit == nil {
+				newit = it.(*StatementIterator)
+			} else {
+				changed = true
+				newit, err = intersect(newit, it.(*StatementIterator))
+				if err != nil {
+					glog.Error(err)
+					return it, false
+				}
+			}
+		} else {
+			unusedIts = append(unusedIts, it)
+		}
+	}
+
+	if !changed {
+		return it, false
+	}
+	if len(unusedIts) == 0 {
+		newit.tagger.CopyFrom(it)
+		return newit, true
+	}
+	newAnd := iterator.NewAnd(qs)
+	newAnd.Tagger().CopyFrom(it)
+	newAnd.AddSubIterator(newit)
+	for _, i := range unusedIts {
+		newAnd.AddSubIterator(i)
+	}
+	return newAnd.Optimize()
+}
+
+func (qs *QuadStore) optimizeHasA(it *iterator.HasA) (graph.Iterator, bool) {
+	subs := it.SubIterators()
+	if len(subs) != 1 {
+		return it, false
+	}
+	primary := subs[0]
+	if primary.Type() == sqlBuilderType {
+		newit, err := hasa(primary.(*StatementIterator), it.Direction())
+		if err != nil {
+			glog.Errorln(err)
+			return it, false
+		}
+		newit.Tagger().CopyFrom(it)
+		return newit, true
+	}
+	return it, false
+}

graph/sql/optimizers_test.go

@@ -0,0 +1,128 @@
+// Copyright 2015 The Cayley Authors. All rights reserved.
+//
+// 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,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sql
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/google/cayley/graph"
+	"github.com/google/cayley/quad"
+)
+
+func TestBuildIntersect(t *testing.T) {
+	a := NewStatementIterator(nil, quad.Subject, "Foo")
+	b := NewStatementIterator(nil, quad.Predicate, "is_equivalent_to")
+	it, err := intersect(a, b)
+	if err != nil {
+		t.Error(err)
+	}
+	s, v := it.buildQuery(false, nil)
+	fmt.Println(s, v)
+}
+
+func TestBuildHasa(t *testing.T) {
+	a := NewStatementIterator(nil, quad.Subject, "Foo")
+	a.tagger.Add("foo")
+	b := NewStatementIterator(nil, quad.Predicate, "is_equivalent_to")
+	it1, err := intersect(a, b)
+	if err != nil {
+		t.Error(err)
+	}
+	it2, err := hasa(it1, quad.Object)
+	if err != nil {
+		t.Error(err)
+	}
+	s, v := it2.buildQuery(false, nil)
+	fmt.Println(s, v)
+}
+
+func TestBuildLinksTo(t *testing.T) {
+	a := NewStatementIterator(nil, quad.Subject, "Foo")
+	b := NewStatementIterator(nil, quad.Predicate, "is_equivalent_to")
+	it1, err := intersect(a, b)
+	if err != nil {
+		t.Error(err)
+	}
+	it2, err := hasa(it1, quad.Object)
+	it2.tagger.Add("foo")
+	if err != nil {
+		t.Error(err)
+	}
+	it3, err := linksto(it2, quad.Subject)
+	if err != nil {
+		t.Error(err)
+	}
+	s, v := it3.buildQuery(false, nil)
+	fmt.Println(s, v)
+}
+
+func TestInterestingQuery(t *testing.T) {
+	if *dbpath == "" {
+		t.SkipNow()
+	}
+	db, err := newQuadStore(*dbpath, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	a := NewStatementIterator(db.(*QuadStore), quad.Object, "Humphrey Bogart")
+	b := NewStatementIterator(db.(*QuadStore), quad.Predicate, "name")
+	it1, err := intersect(a, b)
+	if err != nil {
+		t.Error(err)
+	}
+	it2, err := hasa(it1, quad.Subject)
+	if err != nil {
+		t.Error(err)
+	}
+	it2.Tagger().Add("hb")
+	it3, err := linksto(it2, quad.Object)
+	if err != nil {
+		t.Error(err)
+	}
+	b = NewStatementIterator(db.(*QuadStore), quad.Predicate, "/film/performance/actor")
+	it4, err := intersect(it3, b)
+	if err != nil {
+		t.Error(err)
+	}
+	it5, err := hasa(it4, quad.Subject)
+	if err != nil {
+		t.Error(err)
+	}
+	it6, err := linksto(it5, quad.Object)
+	if err != nil {
+		t.Error(err)
+	}
+	b = NewStatementIterator(db.(*QuadStore), quad.Predicate, "/film/film/starring")
+	it7, err := intersect(it6, b)
+	if err != nil {
+		t.Error(err)
+	}
+	it8, err := hasa(it7, quad.Subject)
+	if err != nil {
+		t.Error(err)
+	}
+	s, v := it8.buildQuery(false, nil)
+	it8.Tagger().Add("id")
+	fmt.Println(s, v)
+	for graph.Next(it8) {
+		fmt.Println(it8.Result())
+		out := make(map[string]graph.Value)
+		it8.TagResults(out)
+		for k, v := range out {
+			fmt.Printf("%s: %v\n", k, v.(string))
+		}
+	}
+}

graph/sql/quadstore.go

@@ -260,41 +260,6 @@ func (qs *QuadStore) Type() string {
 	return QuadStoreType
 }
 
-func (qs *QuadStore) OptimizeIterator(it graph.Iterator) (graph.Iterator, bool) {
-	switch it.Type() {
-	case graph.LinksTo:
-		return qs.optimizeLinksTo(it.(*iterator.LinksTo))
-
-	}
-	return it, false
-}
-
-func (qs *QuadStore) optimizeLinksTo(it *iterator.LinksTo) (graph.Iterator, bool) {
-	subs := it.SubIterators()
-	if len(subs) != 1 {
-		return it, false
-	}
-	primary := subs[0]
-	if primary.Type() == graph.Fixed {
-		size, _ := primary.Size()
-		if size == 1 {
-			if !graph.Next(primary) {
-				panic("unexpected size during optimize")
-			}
-			val := primary.Result()
-			newIt := qs.QuadIterator(it.Direction(), val)
-			nt := newIt.Tagger()
-			nt.CopyFrom(it)
-			for _, tag := range primary.Tagger().Tags() {
-				nt.AddFixed(tag, val)
-			}
-			it.Close()
-			return newIt, true
-		}
-	}
-	return it, false
-}
-
 func (qs *QuadStore) sizeForIterator(isAll bool, dir quad.Direction, val string) int64 {
 	var err error
 	if isAll {