Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Optimize computing reverse reindexing #4755

Merged
merged 1 commit into from
Feb 17, 2020
Merged

Optimize computing reverse reindexing #4755

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
68 changes: 68 additions & 0 deletions dgraph/cmd/alpha/reindex_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -117,3 +117,71 @@ func TestReindexLang(t *testing.T) {
}
}`, res)
}

func TestReindexReverseCount(t *testing.T) {
require.NoError(t, dropAll())
require.NoError(t, alterSchema(`value: [uid] .`))

m1 := `{
set {
<1> <value> <4> .
<1> <value> <5> .
<1> <value> <6> .
<1> <value> <7> .
<1> <value> <8> .
<2> <value> <4> .
<2> <value> <5> .
<2> <value> <6> .
<3> <value> <5> .
<3> <value> <6> .
}
}`
_, err := mutationWithTs(m1, "application/rdf", false, true, 0)
require.NoError(t, err)

// reindex
require.NoError(t, alterSchema(`value: [uid] @count @reverse .`))

q1 := `{
q(func: eq(count(~value), "3")) {
uid
}
}`
res, _, err := queryWithTs(q1, "application/graphql+-", "", 0)
require.NoError(t, err)
require.JSONEq(t, `{
"data": {
"q": [
{
"uid": "0x5"
},
{
"uid": "0x6"
}
]
}
}`, res)

// adding another triplet
m2 := `{ set { <9> <value> <4> . }}`
_, err = mutationWithTs(m2, "application/rdf", false, true, 0)
require.NoError(t, err)

res, _, err = queryWithTs(q1, "application/graphql+-", "", 0)
require.NoError(t, err)
require.JSONEq(t, `{
"data": {
"q": [
{
"uid": "0x4"
},
{
"uid": "0x5"
},
{
"uid": "0x6"
}
]
}
}`, res)
}
49 changes: 37 additions & 12 deletions posting/index.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -172,6 +172,30 @@ func (txn *Txn) addReverseMutationHelper(ctx context.Context, plist *List,
}

func (txn *Txn) addReverseMutation(ctx context.Context, t *pb.DirectedEdge) error {
key := x.ReverseKey(t.Attr, t.ValueId)
plist, err := txn.GetFromDelta(key)
if err != nil {
return err
}
x.AssertTrue(plist != nil)

// We must create a copy here.
edge := &pb.DirectedEdge{
Entity: t.ValueId,
ValueId: t.Entity,
Attr: t.Attr,
Op: t.Op,
Facets: t.Facets,
}
if err := plist.addMutation(ctx, txn, edge); err != nil {
return err
}

ostats.Record(ctx, x.NumEdges.M(1))
return nil
}

func (txn *Txn) addReverseAndCountMutation(ctx context.Context, t *pb.DirectedEdge) error {
key := x.ReverseKey(t.Attr, t.ValueId)
hasCountIndex := schema.State().HasCount(t.Attr)

Expand Down Expand Up @@ -231,7 +255,7 @@ func (l *List) handleDeleteAll(ctx context.Context, edge *pb.DirectedEdge,
case isReversed:
// Delete reverse edge for each posting.
delEdge.ValueId = p.Uid
return txn.addReverseMutation(ctx, delEdge)
return txn.addReverseAndCountMutation(ctx, delEdge)
case isIndexed:
// Delete index edge of each posting.
val := types.Val{
Expand Down Expand Up @@ -282,7 +306,6 @@ func (txn *Txn) addCountMutation(ctx context.Context, t *pb.DirectedEdge, count
}
ostats.Record(ctx, x.NumEdges.M(1))
return nil

}

func (txn *Txn) updateCount(ctx context.Context, params countParams) error {
Expand All @@ -291,9 +314,11 @@ func (txn *Txn) updateCount(ctx context.Context, params countParams) error {
Attr: params.attr,
Op: pb.DirectedEdge_DEL,
}
if err := txn.addCountMutation(ctx, &edge, uint32(params.countBefore),
params.reverse); err != nil {
return err
if params.countBefore > 0 {
if err := txn.addCountMutation(ctx, &edge, uint32(params.countBefore),
params.reverse); err != nil {
return err
}
}

if params.countAfter > 0 {
Expand Down Expand Up @@ -431,7 +456,7 @@ func (l *List) AddMutationWithIndex(ctx context.Context, edge *pb.DirectedEdge,
// Add reverse mutation irrespective of hasMutated, server crash can happen after
// mutation is synced and before reverse edge is synced
if (pstore != nil) && (edge.ValueId != 0) && schema.State().IsReversed(edge.Attr) {
if err := txn.addReverseMutation(ctx, edge); err != nil {
if err := txn.addReverseAndCountMutation(ctx, edge); err != nil {
return err
}
}
Expand Down Expand Up @@ -533,14 +558,12 @@ func (r *rebuilder) Run(ctx context.Context) error {
dbOpts := badger.DefaultOptions(tmpIndexDir).
WithSyncWrites(false).
WithNumVersionsToKeep(math.MaxInt64).
WithLogger(&x.ToGlog{}).
WithCompression(options.None).
WithEventLogging(false).
WithLogRotatesToFlush(10).
WithMaxCacheSize(50) // TODO(Aman): Disable cache altogether

// TODO(Ibrahim): Remove this once badger is updated.
dbOpts.ZSTDCompressionLevel = 1

tmpDB, err := badger.OpenManaged(dbOpts)
if err != nil {
return errors.Wrap(err, "error opening temp badger for reindexing")
Expand All @@ -558,9 +581,6 @@ func (r *rebuilder) Run(ctx context.Context) error {
// Todo(Aman): Replace TxnWriter with WriteBatch. While we do that we should ensure that
// WriteBatch has a mechanism for throttling. Also, find other places where TxnWriter
// could be replaced with WriteBatch in the code
// Todo(Aman): Replace TxnWriter with WriteBatch. While we do that we should ensure that
// WriteBatch has a mechanism for throttling. Also, find other places where TxnWriter
// could be replaced with WriteBatch in the code.
tmpWriter := NewTxnWriter(tmpDB)
stream := pstore.NewStreamAt(r.startTs)
stream.LogPrefix = fmt.Sprintf("Rebuilding index for predicate %s (1/2):", r.attr)
Expand All @@ -583,6 +603,9 @@ func (r *rebuilder) Run(ctx context.Context) error {
return nil, errors.Wrapf(err, "error reading posting list from disk")
}

// We are using different transactions in each call to KeyToList function. This could
// be a problem for computing reverse count indexes if deltas for same key are added
// in different transactions. Such a case doesn't occur for now.
txn := NewTxn(r.startTs)
if err := r.fn(pk.Uid, l, txn); err != nil {
return nil, err
Expand Down Expand Up @@ -1002,6 +1025,8 @@ func rebuildReverseEdges(ctx context.Context, rb *IndexRebuild) error {
edge.Label = pp.Label

for {
// we only need to build reverse index here.
// We will update the reverse count index separately.
err := txn.addReverseMutation(ctx, &edge)
switch err {
case ErrRetry:
Expand Down