Update query_edge_limit config option info and error message.

dgraph/cmd/alpha/run.go

@@ -150,7 +150,7 @@ they form a Raft group and provide synchronous replication.
 
 	flag.Uint64("query_edge_limit", 1e6,
 		"Limit for the maximum number of edges that can be returned in a query."+
-			" This is only useful for shortest path queries.")
+			" This applies to shortest path and recursive queries.")
 
 	// TLS configurations
 	x.RegisterTLSFlags(flag)

query/query3_test.go

@@ -25,11 +25,11 @@ import (
 	"github.com/dgraph-io/dgraph/protos/pb"
 	"github.com/dgraph-io/dgraph/schema"
 	"github.com/dgraph-io/dgraph/types"
+	"github.com/dgraph-io/dgraph/x"
 	"github.com/stretchr/testify/require"
 )
 
 func TestRecurseError(t *testing.T) {
-
 	query := `
 		{
 			me(func: uid(0x01)) @recurse(loop: true) {
@@ -45,6 +45,25 @@ func TestRecurseError(t *testing.T) {
 	require.Contains(t, err.Error(), "Depth must be > 0 when loop is true for recurse query.")
 }
 
+func TestRecurseEdgeLimitError(t *testing.T) {
+	// HACK: Set this flag in the external test cluster when query tests are migrated to
+	// use it.
+	defer func(prev uint64) { x.Config.QueryEdgeLimit = prev }(x.Config.QueryEdgeLimit)
+	x.Config.QueryEdgeLimit = 5
+	query := `
+		{
+			me(func: uid(0x01)) @recurse(loop: true, depth: 2) {
+				friend
+				name
+			}
+		}`
+
+	ctx := defaultContext()
+	_, err := processToFastJsonCtxVars(t, query, ctx, nil)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "Exceeded query edge limit")
+}
+
 func TestRecurseQuery(t *testing.T) {
 
 	query := `
@@ -259,6 +278,24 @@ func TestShortestPath_ExpandError(t *testing.T) {
 	require.Error(t, err)
 }
 
+func TestShortestPath_EdgeLimitError(t *testing.T) {
+	// HACK: Set this flag in the external test cluster when query tests are migrated to
+	// use it.
+	defer func(prev uint64) { x.Config.QueryEdgeLimit = prev }(x.Config.QueryEdgeLimit)
+	x.Config.QueryEdgeLimit = 5
+	query := `
+		{
+			shortest(from:0x01, to:101) {
+              friend
+			}
+		}`
+
+	ctx := defaultContext()
+	_, err := processToFastJsonCtxVars(t, query, ctx, nil)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "Exceeded query edge limit")
+}
+
 func TestShortestPath_NoPath(t *testing.T) {
 
 	query := `

query/recurse.go

@@ -136,8 +136,9 @@ func (start *SubGraph) expandRecurse(ctx context.Context, maxDepth uint64) error
 		}
 
 		if numEdges > x.Config.QueryEdgeLimit {
-			// If we've seen too many nodes, stop the query.
-			return ErrTooBig
+			// If we've seen too many edges, stop the query.
+			return x.Errorf("Exceeded query edge limit = %v. Found %v edges.",
+				x.Config.QueryEdgeLimit, numEdges)
 		}
 
 		if len(out) == 0 {

query/shortest.go

@@ -54,7 +54,6 @@ var pathPool = sync.Pool{
 }
 
 var ErrStop = x.Errorf("STOP")
-var ErrTooBig = x.Errorf("Query exceeded memory limit. Please modify the query")
 var ErrFacet = x.Errorf("Skip the edge")
 
 type priorityQueue []*Item
@@ -203,8 +202,9 @@ func (sg *SubGraph) expandOut(ctx context.Context,
 		}
 
 		if numEdges > x.Config.QueryEdgeLimit {
-			// If we've seen too many nodes, stop the query.
-			rch <- ErrTooBig
+			// If we've seen too many edges, stop the query.
+			rch <- x.Errorf("Exceeded query edge limit = %v. Found %v edges.",
+				x.Config.QueryEdgeLimit, numEdges)
 			return
 		}
 
@@ -315,9 +315,7 @@ func KShortestPath(ctx context.Context, sg *SubGraph) ([]*SubGraph, error) {
 				select {
 				case err = <-expandErr:
 					if err != nil {
-						if err == ErrTooBig {
-							return nil, err
-						} else if err == ErrStop {
+						if err == ErrStop {
 							stopExpansion = true
 						} else {
 							return nil, err
@@ -474,9 +472,7 @@ func ShortestPath(ctx context.Context, sg *SubGraph) ([]*SubGraph, error) {
 			select {
 			case err = <-expandErr:
 				if err != nil {
-					if err == ErrTooBig {
-						return nil, err
-					} else if err == ErrStop {
+					if err == ErrStop {
 						stopExpansion = true
 					} else {
 						return nil, err