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Actually reuse samples in loadWAL across records. 

This cuts walltime by 2.5X and CPU by 2X

Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
This commit is contained in:
Brian Brazil 2018-10-31 14:12:39 +00:00
parent ae91febcbb
commit f0e79ec264
1 changed files with 6 additions and 3 deletions
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9
head.go
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@ -336,6 +336,7 @@ func (h *Head) loadWAL(r *wal.Reader) error {
series []RefSeries
samples []RefSample
tstones []Stone
err error
)
for r.Next() {
series, samples, tstones = series[:0], samples[:0], tstones[:0]
@ -343,7 +344,7 @@ func (h *Head) loadWAL(r *wal.Reader) error {
switch dec.Type(rec) {
case RecordSeries:
series, err := dec.Series(rec, series)
series, err = dec.Series(rec, series)
if err != nil {
return errors.Wrap(err, "decode series")
}
@ -355,7 +356,8 @@ func (h *Head) loadWAL(r *wal.Reader) error {
}
}
case RecordSamples:
samples, err := dec.Samples(rec, samples)
samples, err = dec.Samples(rec, samples)
s := samples
if err != nil {
return errors.Wrap(err, "decode samples")
}
@ -376,8 +378,9 @@ func (h *Head) loadWAL(r *wal.Reader) error {
firstInput <- append(buf[:0], samples[:n]...)
samples = samples[n:]
}
samples = s // Keep whole slice for reuse.
case RecordTombstones:
tstones, err := dec.Tombstones(rec, tstones)
tstones, err = dec.Tombstones(rec, tstones)
if err != nil {
return errors.Wrap(err, "decode tombstones")
}