Support filtering by facets on values.

posting/list.go

@@ -1021,6 +1021,13 @@ func (l *List) ValueFor(readTs uint64, langs []string) (rval types.Val, rerr err
 	return valueToTypesVal(p), nil
 }
 
+// PostingFor returns the posting according to the preferred language list.
+func (l *List) PostingFor(readTs uint64, langs []string) (p *pb.Posting, rerr error) {
+	l.RLock()
+	defer l.RUnlock()
+	return l.postingFor(readTs, langs)
+}
+
 func (l *List) postingFor(readTs uint64, langs []string) (p *pb.Posting, rerr error) {
 	l.AssertRLock() // Avoid recursive locking by asserting a lock here.
 	return l.postingForLangs(readTs, langs)

query/common_test.go

@@ -224,6 +224,7 @@ type Node {
 }
 
 name                           : string @index(term, exact, trigram) @count @lang .
+alt_name                       : [string] @index(term, exact, trigram) @count .
 alias                          : string @index(exact, term, fulltext) .
 abbr                           : string .
 dob                            : dateTime @index(year) .

query/query_facets_test.go

@@ -17,7 +17,6 @@
 package query
 
 import (
-	"context"
 	"fmt"
 	"testing"
 
@@ -35,6 +34,7 @@ func populateClusterWithFacets() {
 	}
 
 	triples := `
+		<1> <name> "Michelle"@en (origin = "french") .
 		<25> <name> "Daryl Dixon" .
 		<31> <name> "Andrea" .
 		<33> <name> "Michale" .
@@ -66,10 +66,12 @@ func populateClusterWithFacets() {
 	triples += fmt.Sprintf("<31> <friend> <1> %s .\n", friendFacets5)
 	triples += fmt.Sprintf("<31> <friend> <25> %s .\n", friendFacets6)
 
-	nameFacets := "(origin = \"french\")"
+	nameFacets := "(origin = \"french\", dummy = true)"
 	triples += fmt.Sprintf("<1> <name> \"Michonne\" %s .\n", nameFacets)
 	triples += fmt.Sprintf("<23> <name> \"Rick Grimes\" %s .\n", nameFacets)
 	triples += fmt.Sprintf("<24> <name> \"Glenn Rhee\" %s .\n", nameFacets)
+	triples += fmt.Sprintf("<1> <alt_name> \"Michelle\" %s .\n", nameFacets)
+	triples += fmt.Sprintf("<1> <alt_name> \"Michelin\" %s .\n", nameFacets)
 
 	addTriplesToCluster(triples)
 
@@ -173,8 +175,8 @@ func TestRetrieveFacetsSimple(t *testing.T) {
 
 	js := processQueryNoErr(t, query)
 	require.JSONEq(t,
-		`{"data":{"me":[{"name|origin":"french","name":"Michonne","gender":"female"}]}}`,
-		js)
+		`{"data":{"me":[{"name|origin":"french","name|dummy":true,"name":"Michonne",
+			"gender":"female"}]}}`, js)
 }
 
 func TestOrderFacets(t *testing.T) {
@@ -275,7 +277,12 @@ func TestRetrieveFacetsUidValues(t *testing.T) {
 
 	js := processQueryNoErr(t, query)
 	require.JSONEq(t,
-		`{"data":{"me":[{"friend":[{"name|origin":"french","name":"Rick Grimes","friend|since":"2006-01-02T15:04:05Z"},{"name|origin":"french","name":"Glenn Rhee","friend|close":true,"friend|family":true,"friend|since":"2004-05-02T15:04:05Z","friend|tag":"Domain3"},{"name":"Daryl Dixon","friend|close":false,"friend|family":true,"friend|since":"2007-05-02T15:04:05Z","friend|tag":34},{"name":"Andrea","friend|since":"2006-01-02T15:04:05Z"},{"friend|age":33,"friend|close":true,"friend|family":false,"friend|since":"2005-05-02T15:04:05Z"}]}]}}`,
+		`{"data":{"me":[{"friend":[
+			{"name|origin":"french","name|dummy":true,"name":"Rick Grimes","friend|since":"2006-01-02T15:04:05Z"},
+			{"name|origin":"french","name|dummy":true,"name":"Glenn Rhee","friend|close":true,"friend|family":true,"friend|since":"2004-05-02T15:04:05Z","friend|tag":"Domain3"},
+			{"name":"Daryl Dixon","friend|close":false,"friend|family":true,"friend|since":"2007-05-02T15:04:05Z","friend|tag":34},
+			{"name":"Andrea","friend|since":"2006-01-02T15:04:05Z"},
+			{"friend|age":33,"friend|close":true,"friend|family":false,"friend|since":"2005-05-02T15:04:05Z"}]}]}}`,
 		js)
 }
 
@@ -296,7 +303,14 @@ func TestRetrieveFacetsAll(t *testing.T) {
 
 	js := processQueryNoErr(t, query)
 	require.JSONEq(t,
-		`{"data":{"me":[{"name|origin":"french","name":"Michonne","friend":[{"name|origin":"french","name":"Rick Grimes","gender":"male","friend|since":"2006-01-02T15:04:05Z"},{"name|origin":"french","name":"Glenn Rhee","friend|close":true,"friend|family":true,"friend|since":"2004-05-02T15:04:05Z","friend|tag":"Domain3"},{"name":"Daryl Dixon","friend|close":false,"friend|family":true,"friend|since":"2007-05-02T15:04:05Z","friend|tag":34},{"name":"Andrea","friend|since":"2006-01-02T15:04:05Z"},{"friend|age":33,"friend|close":true,"friend|family":false,"friend|since":"2005-05-02T15:04:05Z"}],"gender":"female"}]}}`,
+		`{"data":{"me":[
+			{"name|origin":"french","name|dummy":true,"name":"Michonne","friend":[
+				{"name|origin":"french","name|dummy":true,"name":"Rick Grimes","gender":"male","friend|since":"2006-01-02T15:04:05Z"},
+				{"name|origin":"french","name|dummy":true,"name":"Glenn Rhee","friend|close":true,"friend|family":true,"friend|since":"2004-05-02T15:04:05Z","friend|tag":"Domain3"},
+				{"name":"Daryl Dixon","friend|close":false,"friend|family":true,"friend|since":"2007-05-02T15:04:05Z","friend|tag":34},
+				{"name":"Andrea","friend|since":"2006-01-02T15:04:05Z"},
+				{"friend|age":33,"friend|close":true,"friend|family":false,"friend|since":"2005-05-02T15:04:05Z"}],
+			"gender":"female"}]}}`,
 		js)
 }
 
@@ -846,21 +860,119 @@ func TestFacetsFilterAllofAndanyofterms(t *testing.T) {
 		js)
 }
 
-func TestFacetsFilterAtValueFail(t *testing.T) {
+func TestFacetsFilterAtValueBasic(t *testing.T) {
 	populateClusterWithFacets()
-	// facet filtering is not supported at value level.
 	query := `
 	{
-		me(func: uid(1)) {
-			friend {
-				name @facets(eq(origin, "french"))
-			}
+		me(func: has(name)) {
+			name @facets(eq(origin, "french"))
 		}
-	}
-`
+	}`
+
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t,
+		`{"data": {"me":[{"name": "Michonne"}, {"name":"Rick Grimes"}, {"name": "Glenn Rhee"}]}}`,
+		js)
+}
+
+func TestFacetsFilterAtValueListType(t *testing.T) {
+	populateClusterWithFacets()
+	query := `
+	{
+		me(func: has(name)) {
+			alt_name @facets(eq(origin, "french"))
+		}
+	}`
+
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t,
+		`{"data": {"me":[{"alt_name": ["Michelle", "Michelin"]}]}}`, js)
+}
+
+func TestFacetsFilterAtValueComplex(t *testing.T) {
+	populateClusterWithFacets()
+	query := `
+	{
+		me(func: has(name)) {
+			name @facets(eq(origin, "french") AND eq(dummy, false))
+		}
+	}`
+
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t, `{"data": {"me":[]}}`, js)
+}
+
+func TestFacetsFilterAtValueWithLangs(t *testing.T) {
+	populateClusterWithFacets()
+	query := `
+	{
+		me(func: has(name)) {
+			name@en @facets(eq(origin, "french"))
+		}
+	}`
+
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t,
+		`{"data": {"me":[{"name@en": "Michelle"}]}}`, js)
+}
 
-	_, err := processQuery(context.Background(), t, query)
-	require.Error(t, err)
+func TestFacetsFilterAtValueWithBadLang(t *testing.T) {
+	populateClusterWithFacets()
+	query := `
+	{
+		me(func: has(name)) {
+			name@hi @facets(eq(origin, "french"))
+		}
+	}`
+
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t, `{"data": {"me":[]}}`, js)
+}
+
+func TestFacetsFilterAtValueWithFacet(t *testing.T) {
+	populateClusterWithFacets()
+	query := `
+	{
+		me(func: has(name)) {
+			name @facets(eq(origin, "french")) @facets(origin)
+		}
+	}`
+
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t,
+		`{"data": {"me":[{"name": "Michonne", "name|origin": "french"},
+			{"name": "Rick Grimes", "name|origin": "french"},
+			{"name": "Glenn Rhee", "name|origin": "french"}]}}`, js)
+}
+
+func TestFacetsFilterAtValueWithFacetAndLangs(t *testing.T) {
+	populateClusterWithFacets()
+	query := `
+	{
+		me(func: has(name)) {
+			name@en @facets(eq(origin, "french")) @facets(origin)
+		}
+	}`
+
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t,
+		`{"data": {"me":[{"name@en": "Michelle", "name@en|origin": "french"}]}}`, js)
+}
+
+func TestFacetsFilterAtValueWithDifferentFacet(t *testing.T) {
+	populateClusterWithFacets()
+	query := `
+	{
+		me(func: has(name)) {
+			name @facets(eq(dummy, "true")) @facets(origin)
+		}
+	}`
+
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t,
+		`{"data": {"me":[{"name": "Michonne", "name|origin": "french"},
+			{"name": "Rick Grimes", "name|origin": "french"},
+			{"name": "Glenn Rhee", "name|origin": "french"}]}}`, js)
 }
 
 func TestFacetsFilterAndRetrieval(t *testing.T) {

worker/task.go

@@ -38,6 +38,7 @@ import (
 	"github.com/golang/glog"
 	otrace "go.opencensus.io/trace"
 
+	"github.com/golang/protobuf/proto"
 	cindex "github.com/google/codesearch/index"
 	cregexp "github.com/google/codesearch/regexp"
 	"github.com/pkg/errors"
@@ -342,7 +343,7 @@ func (qs *queryState) handleValuePostings(ctx context.Context, args funcArgs) er
 		return nil
 	}
 
-	// This function has small boiletplate as handleUidPostings, around how the code gets
+	// This function has small boilerplate as handleUidPostings, around how the code gets
 	// concurrently executed. I didn't see much value in trying to separate it out, because the core
 	// logic constitutes most of the code volume here.
 	numGo, width := x.DivideAndRule(srcFn.n)
@@ -371,24 +372,16 @@ func (qs *queryState) handleValuePostings(ctx context.Context, args funcArgs) er
 			if err != nil {
 				return err
 			}
-			var vals []types.Val
-			if q.ExpandAll {
-				vals, err = pl.AllValues(args.q.ReadTs)
-			} else if listType && len(q.Langs) == 0 {
-				vals, err = pl.AllUntaggedValues(args.q.ReadTs)
-			} else {
-				var val types.Val
-				val, err = pl.ValueFor(args.q.ReadTs, q.Langs)
-				vals = append(vals, val)
-			}
 
+			vals, fcs, err := retrieveValuesAndFacets(args, pl, listType)
 			if err == posting.ErrNoValue || len(vals) == 0 {
 				out.UidMatrix = append(out.UidMatrix, &pb.List{})
 				out.FacetMatrix = append(out.FacetMatrix, &pb.FacetsList{})
 				if q.DoCount {
 					out.Counts = append(out.Counts, 0)
 				} else {
-					out.ValueMatrix = append(out.ValueMatrix, &pb.ValueList{Values: []*pb.TaskValue{}})
+					out.ValueMatrix = append(out.ValueMatrix,
+						&pb.ValueList{Values: []*pb.TaskValue{}})
 					if q.ExpandAll {
 						// To keep the cardinality same as that of ValueMatrix.
 						out.LangMatrix = append(out.LangMatrix, &pb.LangList{})
@@ -432,22 +425,9 @@ func (qs *queryState) handleValuePostings(ctx context.Context, args funcArgs) er
 			}
 			out.ValueMatrix = append(out.ValueMatrix, &vl)
 
-			if q.FacetsFilter != nil { // else part means isValueEdge
-				// This is Value edge and we are asked to do facet filtering. Not supported.
-				return errors.Errorf("Facet filtering is not supported on values.")
-			}
-
-			// add facets to result.
-			if q.FacetParam != nil {
-				fs, err := pl.Facets(args.q.ReadTs, q.FacetParam, q.Langs)
-				if err != nil {
-					fs = []*api.Facet{}
-				}
-				out.FacetMatrix = append(out.FacetMatrix,
-					&pb.FacetsList{FacetsList: []*pb.Facets{{Facets: fs}}})
-			} else {
-				out.FacetMatrix = append(out.FacetMatrix, &pb.FacetsList{})
-			}
+			// Add facets to result.
+			out.FacetMatrix = append(out.FacetMatrix,
+				&pb.FacetsList{FacetsList: []*pb.Facets{{Facets: fcs}}})
 
 			switch {
 			case q.DoCount:
@@ -513,6 +493,86 @@ func (qs *queryState) handleValuePostings(ctx context.Context, args funcArgs) er
 	return nil
 }
 
+func retrieveValuesAndFacets(args funcArgs, pl *posting.List, listType bool) (
+	[]types.Val, []*api.Facet, error) {
+	q := args.q
+	var err error
+	var vals []types.Val
+	var fcs []*api.Facet
+
+	// Retrieve values when facet filtering is not being requested.
+	if q.FacetsFilter == nil {
+		// Retrieve values.
+		if q.ExpandAll {
+			vals, err = pl.AllValues(args.q.ReadTs)
+		} else if listType && len(q.Langs) == 0 {
+			vals, err = pl.AllUntaggedValues(args.q.ReadTs)
+		} else {
+			var val types.Val
+			val, err = pl.ValueFor(args.q.ReadTs, q.Langs)
+			vals = append(vals, val)
+		}
+		if err != nil {
+			return nil, nil, err
+		}
+
+		// Retrieve facets.
+		if q.FacetParam != nil {
+			fcs, err = pl.Facets(args.q.ReadTs, q.FacetParam, q.Langs)
+		}
+		if err != nil {
+			return nil, nil, err
+		}
+
+		return vals, fcs, nil
+	}
+
+	// Retrieve values when facet filtering is being requested.
+	facetsTree, err := preprocessFilter(q.FacetsFilter)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Retrieve the posting that matches the language preferences.
+	langMatch, err := pl.PostingFor(q.ReadTs, q.Langs)
+	if err != nil && err != posting.ErrNoValue {
+		return nil, nil, err
+	}
+	err = pl.Iterate(q.ReadTs, 0, func(p *pb.Posting) error {
+		if listType && len(q.Langs) == 0 {
+			// Don't retrieve tagged values unless explicitly asked.
+			if len(p.LangTag) > 0 {
+				return nil
+			}
+		} else {
+			// Only consider the posting that matches our language preferences.
+			if !proto.Equal(p, langMatch) {
+				return nil
+			}
+		}
+
+		picked, err := applyFacetsTree(p.Facets, facetsTree)
+		if err != nil {
+			return err
+		}
+		if picked {
+			vals = append(vals, types.Val{
+				Tid:   types.TypeID(p.ValType),
+				Value: p.Value,
+			})
+			if q.FacetParam != nil {
+				fcs = append(fcs, facets.CopyFacets(p.Facets, q.FacetParam)...)
+			}
+		}
+		return nil // continue iteration.
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return vals, fcs, nil
+}
+
 // This function handles operations on uid posting lists. Index keys, reverse keys and some data
 // keys store uid posting lists.
 func (qs *queryState) handleUidPostings(