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Wrap errors thrown in posting/list.go for easier debugging. #4880

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merged 1 commit into from
Mar 4, 2020
Merged

Wrap errors thrown in posting/list.go for easier debugging. #4880

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75 changes: 47 additions & 28 deletions posting/list.go
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Original file line number Diff line number Diff line change
Expand Up @@ -110,7 +110,8 @@ func (it *pIterator) init(l *List, afterUid, deleteBelowTs uint64) error {
if len(it.l.plist.Splits) > 0 {
plist, err := l.readListPart(it.l.plist.Splits[it.splitIdx])
if err != nil {
return err
return errors.Wrapf(
err, "cannot read initial list part for list with base key %v", l.key)
}
it.plist = plist
} else {
Expand Down Expand Up @@ -165,7 +166,8 @@ func (it *pIterator) moveToNextPart() error {
it.splitIdx++
plist, err := it.l.readListPart(it.l.plist.Splits[it.splitIdx])
if err != nil {
return err
return errors.Wrapf(err, "cannot move to next list part in iterator for list with key %v",
it.l.key)
}
it.plist = plist

Expand Down Expand Up @@ -222,7 +224,8 @@ func (it *pIterator) next() error {
it.uidx = 0
it.uids = it.dec.Next()

return it.moveToNextValidPart()
return errors.Wrapf(it.moveToNextValidPart(), "cannot advance iterator for list with key %v",
it.l.key)
}

func (it *pIterator) valid() (bool, error) {
Expand All @@ -233,7 +236,7 @@ func (it *pIterator) valid() (bool, error) {
err := it.moveToNextValidPart()
switch {
case err != nil:
return false, err
return false, errors.Wrapf(err, "cannot advance iterator when calling pIterator.valid")
case len(it.uids) > 0:
return true, nil
default:
Expand Down Expand Up @@ -404,7 +407,8 @@ func (l *List) addMutationInternal(ctx context.Context, txn *Txn, t *pb.Directed
var conflictKey uint64
pk, err := x.Parse(l.key)
if err != nil {
return err
return errors.Wrapf(err, "cannot parse key when adding mutation to list with key %v",
l.key)
}
switch {
case schema.State().HasNoConflict(t.Attr):
Expand Down Expand Up @@ -579,7 +583,7 @@ func (l *List) iterate(readTs uint64, afterUid uint64, f func(obj *pb.Posting) e
)
err = pitr.init(l, afterUid, deleteBelowTs)
if err != nil {
return err
return errors.Wrapf(err, "cannot initialize iterator when calling List.iterate")
}

loop:
Expand Down Expand Up @@ -660,7 +664,7 @@ func (l *List) IsEmpty(readTs, afterUid uint64) (bool, error) {
return ErrStopIteration
})
if err != nil {
return false, err
return false, errors.Wrapf(err, "cannot iterate over list when calling List.IsEmpty")
}
return count == 0, nil
}
Expand Down Expand Up @@ -709,7 +713,7 @@ func (l *List) Rollup() ([]*bpb.KV, error) {
defer l.RUnlock()
out, err := l.rollup(math.MaxUint64, true)
if err != nil {
return nil, err
return nil, errors.Wrapf(err, "failed when calling List.rollup")
}
if out == nil {
return nil, nil
Expand All @@ -727,7 +731,10 @@ func (l *List) Rollup() ([]*bpb.KV, error) {
for startUid, plist := range out.parts {
// Any empty posting list would still have BitEmpty set. And the main posting list
// would NOT have that posting list startUid in the splits list.
kv := out.marshalPostingListPart(l.key, startUid, plist)
kv, err := out.marshalPostingListPart(l.key, startUid, plist)
if err != nil {
return nil, errors.Wrapf(err, "cannot marshaling posting list parts")
}
kvs = append(kvs, kv)
}

Expand All @@ -742,7 +749,7 @@ func (l *List) SingleListRollup() (*bpb.KV, error) {

out, err := l.rollup(math.MaxUint64, false)
if err != nil {
return nil, err
return nil, errors.Wrapf(err, "failed when calling List.rollup")
}
// out is only nil when the list's minTs is greater than readTs but readTs
// is math.MaxUint64 so that's not possible. Assert that's true.
Expand All @@ -759,17 +766,21 @@ func (l *List) SingleListRollup() (*bpb.KV, error) {
}

func (out *rollupOutput) marshalPostingListPart(
baseKey []byte, startUid uint64, plist *pb.PostingList) *bpb.KV {
baseKey []byte, startUid uint64, plist *pb.PostingList) (*bpb.KV, error) {
kv := &bpb.KV{}
kv.Version = out.newMinTs
key, err := x.GetSplitKey(baseKey, startUid)
x.Check(err)
if err != nil {
return nil, errors.Wrapf(err,
"cannot generate split key for list with base key %v and start UID %d",
baseKey, startUid)
}
kv.Key = key
val, meta := marshalPostingList(plist)
kv.UserMeta = []byte{meta}
kv.Value = val

return kv
return kv, nil
}

func marshalPostingList(plist *pb.PostingList) ([]byte, byte) {
Expand Down Expand Up @@ -922,7 +933,7 @@ func (l *List) Uids(opt ListOptions) (*pb.List, error) {
})
l.RUnlock()
if err != nil {
return out, err
return out, errors.Wrapf(err, "cannot retrieve UIDs from list with key %v", l.key)
}

// Do The intersection here as it's optimized.
Expand All @@ -939,12 +950,13 @@ func (l *List) Postings(opt ListOptions, postFn func(*pb.Posting) error) error {
l.RLock()
defer l.RUnlock()

return l.iterate(opt.ReadTs, opt.AfterUid, func(p *pb.Posting) error {
err := l.iterate(opt.ReadTs, opt.AfterUid, func(p *pb.Posting) error {
if p.PostingType != pb.Posting_REF {
return nil
}
return postFn(p)
})
return errors.Wrapf(err, "cannot retrieve postings from list with key %v", l.key)
}

// AllUntaggedValues returns all the values in the posting list with no language tag.
Expand All @@ -962,7 +974,7 @@ func (l *List) AllUntaggedValues(readTs uint64) ([]types.Val, error) {
}
return nil
})
return vals, err
return vals, errors.Wrapf(err, "cannot retrieve untagged values from list with key %v", l.key)
}

// allUntaggedFacets returns facets for all untagged values. Since works well only for
Expand All @@ -977,7 +989,7 @@ func (l *List) allUntaggedFacets(readTs uint64) ([]*pb.Facets, error) {
return nil
})

return facets, err
return facets, errors.Wrapf(err, "cannot retrieve untagged facets from list with key %v", l.key)
}

// AllValues returns all the values in the posting list.
Expand All @@ -993,7 +1005,7 @@ func (l *List) AllValues(readTs uint64) ([]types.Val, error) {
})
return nil
})
return vals, err
return vals, errors.Wrapf(err, "cannot retrieve all values from list with key %v", l.key)
}

// GetLangTags finds the language tags of each posting in the list.
Expand All @@ -1006,7 +1018,7 @@ func (l *List) GetLangTags(readTs uint64) ([]string, error) {
tags = append(tags, string(p.LangTag))
return nil
})
return tags, err
return tags, errors.Wrapf(err, "cannot retrieve language tags from list with key %v", l.key)
}

// Value returns the default value from the posting list. The default value is
Expand All @@ -1016,7 +1028,8 @@ func (l *List) Value(readTs uint64) (rval types.Val, rerr error) {
defer l.RUnlock()
val, found, err := l.findValue(readTs, math.MaxUint64)
if err != nil {
return val, err
return val, errors.Wrapf(err,
"cannot retrieve default value from list with key %v", l.key)
}
if !found {
return val, ErrNoValue
Expand All @@ -1034,7 +1047,8 @@ func (l *List) ValueFor(readTs uint64, langs []string) (rval types.Val, rerr err
defer l.RUnlock()
p, err := l.postingFor(readTs, langs)
if err != nil {
return rval, err
return rval, errors.Wrapf(err,
"cannot retrieve value with langs %v from list with key %v", langs, l.key)
}
return valueToTypesVal(p), nil
}
Expand Down Expand Up @@ -1091,7 +1105,8 @@ func (l *List) postingForLangs(readTs uint64, langs []string) (*pb.Posting, erro
found, pos, err := l.findPosting(readTs, math.MaxUint64)
switch {
case err != nil:
return nil, err
return nil, errors.Wrapf(err,
"cannot find value without language tag from list with key %v", l.key)
case found:
return pos, nil
}
Expand All @@ -1110,7 +1125,8 @@ func (l *List) postingForLangs(readTs uint64, langs []string) (*pb.Posting, erro
return nil
})
if err != nil {
return nil, err
return nil, errors.Wrapf(err,
"cannot retrieve value with the smallest lang UID from list with key %v", l.key)
}
}

Expand Down Expand Up @@ -1155,7 +1171,8 @@ func (l *List) findPosting(readTs uint64, uid uint64) (found bool, pos *pb.Posti
return ErrStopIteration
})

return found, pos, err
return found, pos, errors.Wrapf(err,
"cannot retrieve posting for UID %d from list with key %v", uid, l.key)
}

// Facets gives facets for the posting representing value.
Expand All @@ -1169,17 +1186,18 @@ func (l *List) Facets(readTs uint64, param *pb.FacetParams, langs []string,
if listType {
fs, err := l.allUntaggedFacets(readTs)
if err != nil {
return nil, err
return nil, errors.Wrapf(err, "cannot retrieve facets for predicate of list type")
}

for _, fcts := range fs {
fcs = append(fcs, &pb.Facets{Facets: facets.CopyFacets(fcts.Facets, param)})
}
return fcs, nil
}

p, err := l.postingFor(readTs, langs)
if err != nil {
return nil, err
return nil, errors.Wrapf(err, "cannot retrieve facet")
}
fcs = append(fcs, &pb.Facets{Facets: facets.CopyFacets(p.Facets, param)})
return fcs, nil
Expand All @@ -1188,7 +1206,8 @@ func (l *List) Facets(readTs uint64, param *pb.FacetParams, langs []string,
func (l *List) readListPart(startUid uint64) (*pb.PostingList, error) {
key, err := x.GetSplitKey(l.key, startUid)
if err != nil {
return nil, err
return nil, errors.Wrapf(err,
"cannot generate key for list with base key %v and start UID %d", l.key, startUid)
}
txn := pstore.NewTransactionAt(l.minTs, false)
item, err := txn.Get(key)
Expand All @@ -1197,7 +1216,7 @@ func (l *List) readListPart(startUid uint64) (*pb.PostingList, error) {
}
part := &pb.PostingList{}
if err := unmarshalOrCopy(part, item); err != nil {
return nil, err
return nil, errors.Wrapf(err, "cannot unmarshal list part with key %v", key)
}
return part, nil
}
Expand Down