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lib/storage: do not change timestamps to constant rate if values are constant or have constant delta

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This breaks the original timestamps, which results in issues like
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/120 and
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/141 .
This commit is contained in:
Aliaksandr Valialkin 2019-08-06 15:35:04 +03:00
parent b8bb74ffc6
commit 0b488f1e37
1 changed files with 0 additions and 13 deletions
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13
lib/storage/block.go
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@ -205,19 +205,6 @@ func (b *Block) MarshalData(timestampsBlockOffset, valuesBlockOffset uint64) ([]
b.bh.ValuesBlockSize = uint32(len(b.valuesData))
b.values = b.values[:0]
if len(timestamps) > 1 && (b.bh.ValuesMarshalType == encoding.MarshalTypeConst || b.bh.ValuesMarshalType == encoding.MarshalTypeDeltaConst) {
// Special case - values are constant or are changed with constant rate.
// In this case we may 'cheat' by assuming timestamps are changed
// at ideal constant rate. This improves timestamps' compression rate.
minTimestamp := timestamps[0]
maxTimestamp := timestamps[len(timestamps)-1]
delta := (maxTimestamp - minTimestamp) / int64(len(timestamps)-1)
ts := minTimestamp
for i := 1; i < len(timestamps); i++ {
ts += delta
timestamps[i] = ts
}
}
b.timestampsData, b.bh.TimestampsMarshalType, b.bh.MinTimestamp = encoding.MarshalTimestamps(b.timestampsData[:0], timestamps, b.bh.PrecisionBits)
b.bh.TimestampsBlockOffset = timestampsBlockOffset
b.bh.TimestampsBlockSize = uint32(len(b.timestampsData))