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Commit af560bd

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author
Harshil goel
committed
add single key call
1 parent c22acb6 commit af560bd

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3 files changed

+181
-35
lines changed

3 files changed

+181
-35
lines changed

‎posting/list_test.go

+48
Original file line numberDiff line numberDiff line change
@@ -450,6 +450,54 @@ func TestAddMutation_mrjn1(t *testing.T) {
450450
require.Equal(t, 0, ol.Length(txn.StartTs, 0))
451451
}
452452

453+
func TestReadSingleValue(t *testing.T) {
454+
defer setMaxListSize(maxListSize)
455+
maxListSize = math.MaxInt32
456+
457+
// We call pl.Iterate and then stop iterating in the first loop when we are reading
458+
// single values. This test confirms that the two functions, getFirst from this file
459+
// and GetSingeValueForKey works without an issue.
460+
461+
key := x.DataKey(x.GalaxyAttr("value"), 1240)
462+
ol, err := getNew(key, ps, math.MaxUint64)
463+
require.NoError(t, err)
464+
N := int(10000)
465+
for i := 2; i <= N; i += 2 {
466+
edge := &pb.DirectedEdge{
467+
Value: []byte("ho hey there" + strconv.Itoa(i)),
468+
}
469+
txn := Txn{StartTs: uint64(i)}
470+
addMutationHelper(t, ol, edge, Set, &txn)
471+
require.NoError(t, ol.commitMutation(uint64(i), uint64(i)+1))
472+
kData := ol.getMutation(uint64(i))
473+
writer := NewTxnWriter(pstore)
474+
if err := writer.SetAt(key, kData, BitDeltaPosting, uint64(i)); err != nil {
475+
require.NoError(t, err)
476+
}
477+
writer.Flush()
478+
479+
if i%10 == 0 {
480+
// Do frequent rollups, and store data in old timestamp
481+
kvs, err := ol.Rollup(nil, txn.StartTs-3)
482+
require.NoError(t, err)
483+
require.NoError(t, writePostingListToDisk(kvs))
484+
ol, err = getNew(key, ps, math.MaxUint64)
485+
require.NoError(t, err)
486+
}
487+
488+
j := 2
489+
if j < int(ol.minTs) {
490+
j = int(ol.minTs)
491+
}
492+
for ; j < i+6; j++ {
493+
tx := NewTxn(uint64(j))
494+
k, err := tx.cache.GetSinglePosting(key)
495+
require.NoError(t, err)
496+
checkValue(t, ol, string(k.Postings[0].Value), uint64(j))
497+
}
498+
}
499+
}
500+
453501
func TestRollupMaxTsIsSet(t *testing.T) {
454502
defer setMaxListSize(maxListSize)
455503
maxListSize = math.MaxInt32

‎posting/lists.go

+64
Original file line numberDiff line numberDiff line change
@@ -323,6 +323,70 @@ func (lc *LocalCache) getInternal(key []byte, readFromDisk bool) (*List, error)
323323
return lc.SetIfAbsent(skey, pl), nil
324324
}
325325

326+
// GetSinglePosting retrieves the cached version of the first item in the list associated with the
327+
// given key. This is used for retrieving the value of a scalar predicats.
328+
func (lc *LocalCache) GetSinglePosting(key []byte) (*pb.PostingList, error) {
329+
getDeltas := func() *pb.PostingList {
330+
lc.RLock()
331+
defer lc.RUnlock()
332+
333+
pl := &pb.PostingList{}
334+
if delta, ok := lc.deltas[string(key)]; ok && len(delta) > 0 {
335+
err := pl.Unmarshal(delta)
336+
if err != nil {
337+
return pl
338+
}
339+
}
340+
341+
return nil
342+
}
343+
344+
getPostings := func() (*pb.PostingList, error) {
345+
pl := getDeltas()
346+
if pl != nil {
347+
return pl, nil
348+
}
349+
350+
pl = &pb.PostingList{}
351+
txn := pstore.NewTransactionAt(lc.startTs, false)
352+
item, err := txn.Get(key)
353+
if err != nil {
354+
return nil, err
355+
}
356+
357+
err = item.Value(func(val []byte) error {
358+
if err := pl.Unmarshal(val); err != nil {
359+
return err
360+
}
361+
return nil
362+
})
363+
364+
return pl, err
365+
}
366+
367+
pl, err := getPostings()
368+
if err == badger.ErrKeyNotFound {
369+
return nil, nil
370+
}
371+
if err != nil {
372+
return nil, err
373+
}
374+
375+
// Filter and remove STAR_ALL and OP_DELETE Postings
376+
idx := 0
377+
for _, postings := range pl.Postings {
378+
if hasDeleteAll(postings) {
379+
return nil, nil
380+
}
381+
if postings.Op != Del {
382+
pl.Postings[idx] = postings
383+
idx++
384+
}
385+
}
386+
pl.Postings = pl.Postings[:idx]
387+
return pl, nil
388+
}
389+
326390
// Get retrieves the cached version of the list associated with the given key.
327391
func (lc *LocalCache) Get(key []byte) (*List, error) {
328392
return lc.getInternal(key, true)

‎worker/task.go

+69-35
Original file line numberDiff line numberDiff line change
@@ -420,6 +420,14 @@ func (qs *queryState) handleValuePostings(ctx context.Context, args funcArgs) er
420420
outputs := make([]*pb.Result, numGo)
421421
listType := schema.State().IsList(q.Attr)
422422

423+
// These are certain special cases where we can get away with reading only the latest value
424+
// Lang doesn't work because we would be storing various different languages at various
425+
// time. So when we go to read the latest value, we might get a different language.
426+
// Similarly with DoCount and ExpandAll and Facets. List types are also not supported
427+
// because list is stored by time, and we combine all the list items at various timestamps.
428+
hasLang := schema.State().HasLang(q.Attr)
429+
getMultiplePosting := q.DoCount || q.ExpandAll || listType || hasLang || q.FacetParam != nil
430+
423431
calculate := func(start, end int) error {
424432
x.AssertTrue(start%width == 0)
425433
out := &pb.Result{}
@@ -434,49 +442,75 @@ func (qs *queryState) handleValuePostings(ctx context.Context, args funcArgs) er
434442
key := x.DataKey(q.Attr, q.UidList.Uids[i])
435443

436444
// Get or create the posting list for an entity, attribute combination.
437-
pl, err := qs.cache.Get(key)
438-
if err != nil {
439-
return err
440-
}
441445

442-
// If count is being requested, there is no need to populate value and facets matrix.
443-
if q.DoCount {
444-
count, err := countForValuePostings(args, pl, facetsTree, listType)
445-
if err != nil && err != posting.ErrNoValue {
446+
var vals []types.Val
447+
fcs := &pb.FacetsList{FacetsList: make([]*pb.Facets, 0)} // TODO Figure out how it is stored
448+
449+
if !getMultiplePosting {
450+
pl, err := qs.cache.GetSinglePosting(key)
451+
if err != nil {
452+
return err
453+
}
454+
if pl == nil || len(pl.Postings) == 0 {
455+
out.UidMatrix = append(out.UidMatrix, &pb.List{})
456+
out.FacetMatrix = append(out.FacetMatrix, &pb.FacetsList{})
457+
out.ValueMatrix = append(out.ValueMatrix,
458+
&pb.ValueList{Values: []*pb.TaskValue{}})
459+
continue
460+
}
461+
vals = make([]types.Val, len(pl.Postings))
462+
for i, p := range pl.Postings {
463+
vals[i] = types.Val{
464+
Tid: types.TypeID(p.ValType),
465+
Value: p.Value,
466+
}
467+
}
468+
} else {
469+
pl, err := qs.cache.Get(key)
470+
if err != nil {
446471
return err
447472
}
448-
out.Counts = append(out.Counts, uint32(count))
449-
// Add an empty UID list to make later processing consistent.
450-
out.UidMatrix = append(out.UidMatrix, &pb.List{})
451-
continue
452-
}
453473

454-
vals, fcs, err := retrieveValuesAndFacets(args, pl, facetsTree, listType)
455-
switch {
456-
case err == posting.ErrNoValue || (err == nil && len(vals) == 0):
457-
// This branch is taken when the value does not exist in the pl or
458-
// the number of values retrieved is zero (there could still be facets).
459-
// We add empty lists to the UidMatrix, FaceMatrix, ValueMatrix and
460-
// LangMatrix so that all these data structure have predictable layouts.
461-
out.UidMatrix = append(out.UidMatrix, &pb.List{})
462-
out.FacetMatrix = append(out.FacetMatrix, &pb.FacetsList{})
463-
out.ValueMatrix = append(out.ValueMatrix,
464-
&pb.ValueList{Values: []*pb.TaskValue{}})
465-
if q.ExpandAll {
466-
// To keep the cardinality same as that of ValueMatrix.
467-
out.LangMatrix = append(out.LangMatrix, &pb.LangList{})
474+
// If count is being requested, there is no need to populate value and facets matrix.
475+
if q.DoCount {
476+
count, err := countForValuePostings(args, pl, facetsTree, listType)
477+
if err != nil && err != posting.ErrNoValue {
478+
return err
479+
}
480+
out.Counts = append(out.Counts, uint32(count))
481+
// Add an empty UID list to make later processing consistent.
482+
out.UidMatrix = append(out.UidMatrix, &pb.List{})
483+
continue
468484
}
469-
continue
470-
case err != nil:
471-
return err
472-
}
473485

474-
if q.ExpandAll {
475-
langTags, err := pl.GetLangTags(args.q.ReadTs)
476-
if err != nil {
486+
vals, fcs, err = retrieveValuesAndFacets(args, pl, facetsTree, listType)
487+
488+
switch {
489+
case err == posting.ErrNoValue || (err == nil && len(vals) == 0):
490+
// This branch is taken when the value does not exist in the pl or
491+
// the number of values retrieved is zero (there could still be facets).
492+
// We add empty lists to the UidMatrix, FaceMatrix, ValueMatrix and
493+
// LangMatrix so that all these data structure have predictable layouts.
494+
out.UidMatrix = append(out.UidMatrix, &pb.List{})
495+
out.FacetMatrix = append(out.FacetMatrix, &pb.FacetsList{})
496+
out.ValueMatrix = append(out.ValueMatrix,
497+
&pb.ValueList{Values: []*pb.TaskValue{}})
498+
if q.ExpandAll {
499+
// To keep the cardinality same as that of ValueMatrix.
500+
out.LangMatrix = append(out.LangMatrix, &pb.LangList{})
501+
}
502+
continue
503+
case err != nil:
477504
return err
478505
}
479-
out.LangMatrix = append(out.LangMatrix, &pb.LangList{Lang: langTags})
506+
507+
if q.ExpandAll {
508+
langTags, err := pl.GetLangTags(args.q.ReadTs)
509+
if err != nil {
510+
return err
511+
}
512+
out.LangMatrix = append(out.LangMatrix, &pb.LangList{Lang: langTags})
513+
}
480514
}
481515

482516
uidList := new(pb.List)

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