https://github.com/google/cayley
Tip revision: 1ee1c6ab2c80df0b08b6766187f8088357fd507a authored by sah607 on 21 September 2017, 20:53:57 UTC
Add Elastic Iterator
Add Elastic Iterator
Tip revision: 1ee1c6a
quadstore_iterator_optimize.go
// Copyright 2014 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 mongo
import (
"time"
"gopkg.in/mgo.v2/bson"
"github.com/cayleygraph/cayley/clog"
"github.com/cayleygraph/cayley/graph"
"github.com/cayleygraph/cayley/graph/iterator"
"github.com/cayleygraph/cayley/quad"
)
func (qs *QuadStore) OptimizeIterator(it graph.Iterator) (graph.Iterator, bool) {
switch it.Type() {
case graph.LinksTo:
return qs.optimizeLinksTo(it.(*iterator.LinksTo))
case graph.And:
return qs.optimizeAndIterator(it.(*iterator.And))
case graph.Comparison:
return qs.optimizeComparison(it.(*iterator.Comparison))
}
return it, false
}
func (qs *QuadStore) optimizeAndIterator(it *iterator.And) (graph.Iterator, bool) {
// Fail fast if nothing can happen
if clog.V(4) {
clog.Infof("Entering optimizeAndIterator %v", it.UID())
}
found := false
for _, it := range it.SubIterators() {
if clog.V(4) {
clog.Infof("%v", it.Type())
}
if _, ok := it.(*Iterator); ok {
found = true
}
}
if !found {
if clog.V(4) {
clog.Infof("Aborting optimizeAndIterator")
}
return it, false
}
newAnd := iterator.NewAnd(qs)
var mongoIt *Iterator
for _, it := range it.SubIterators() {
if sit, ok := it.(*Iterator); ok {
if mongoIt == nil {
mongoIt = sit
} else {
newAnd.AddSubIterator(it)
}
continue
}
switch it.Type() {
case graph.LinksTo:
continue
default:
newAnd.AddSubIterator(it)
}
}
stats := mongoIt.Stats()
lset := []graph.Linkage{
{
Dir: mongoIt.dir,
Value: mongoIt.hash,
},
}
n := 0
for _, it := range it.SubIterators() {
if it.Type() == graph.LinksTo {
lto := it.(*iterator.LinksTo)
// Is it more effective to do the replacement, or let the mongo check the linksto?
ltostats := lto.Stats()
if (ltostats.ContainsCost+stats.NextCost)*stats.Size > (ltostats.NextCost+stats.ContainsCost)*ltostats.Size {
continue
}
newLto := NewLinksTo(qs, lto.SubIterators()[0], "quads", lto.Direction(), lset)
newAnd.AddSubIterator(newLto)
n++
}
}
if n == 0 {
return it, false
}
return newAnd.Optimize()
}
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 !primary.Next() {
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) optimizeComparison(it *iterator.Comparison) (graph.Iterator, bool) {
subs := it.SubIterators()
if len(subs) != 1 {
return it, false
}
mit, ok := subs[0].(*Iterator)
if !ok || !mit.isAll {
return it, false
}
name := ""
switch it.Operator() {
case iterator.CompareGT:
name = "$gt"
case iterator.CompareGTE:
name = "$gte"
case iterator.CompareLT:
name = "$lt"
case iterator.CompareLTE:
name = "$lte"
default:
return it, false
}
var constraint bson.M
const base = "Name"
switch v := it.Value().(type) {
case quad.String:
constraint = bson.M{
base + ".val": bson.M{name: string(v)},
base + ".iri": bson.M{"$ne": true},
base + ".bnode": bson.M{"$ne": true},
}
case quad.IRI:
constraint = bson.M{
base + ".val": bson.M{name: string(v)},
base + ".iri": true,
}
case quad.BNode:
constraint = bson.M{
base + ".val": bson.M{name: string(v)},
base + ".bnode": true,
}
case quad.Int:
constraint = bson.M{
base: bson.M{name: int64(v)},
}
case quad.Float:
constraint = bson.M{
base: bson.M{name: float64(v)},
}
case quad.Time:
constraint = bson.M{
base: bson.M{name: time.Time(v)},
}
default:
return it, false
}
return NewIteratorWithConstraints(qs, mit.collection, constraint), true
}