Commit graph

18 commits

Author SHA1 Message Date
Oleksandr Redko
9fff48c3e3
app,lib: fix typos in comments (#3804) 2023-02-13 13:27:13 +01:00
Aliaksandr Valialkin
5b9e6b9d24
lib/storage: follow-up after 7c0ae3a86a
- Update docs at https://docs.victoriametrics.com/#deduplication
- Optimize the deduplication loop a bit

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3333
2022-12-08 18:16:57 -08:00
Roman Khavronenko
7c0ae3a86a
lib/storage: keep sample with the biggest value on timestamp conflict (#3421)
The change leaves raw sample with the biggest value for identical
timestamps per each `-dedup.minScrapeInterval` discrete interval
when the deduplication is enabled.

```
benchstat old.txt new.txt
name                                         old time/op    new time/op    delta
DeduplicateSamples/minScrapeInterval=1s-10      817ns ± 2%     832ns ± 3%      ~     (p=0.052 n=10+10)
DeduplicateSamples/minScrapeInterval=2s-10     1.56µs ± 1%    2.12µs ± 0%   +35.19%  (p=0.000 n=9+7)
DeduplicateSamples/minScrapeInterval=5s-10     1.32µs ± 3%    1.65µs ± 2%   +25.57%  (p=0.000 n=10+10)
DeduplicateSamples/minScrapeInterval=10s-10    1.13µs ± 2%    1.50µs ± 1%   +32.85%  (p=0.000 n=10+10)

name                                         old speed      new speed      delta
DeduplicateSamples/minScrapeInterval=1s-10   10.0GB/s ± 2%   9.9GB/s ± 3%      ~     (p=0.052 n=10+10)
DeduplicateSamples/minScrapeInterval=2s-10   5.24GB/s ± 1%  3.87GB/s ± 0%   -26.03%  (p=0.000 n=9+7)
DeduplicateSamples/minScrapeInterval=5s-10   6.22GB/s ± 3%  4.96GB/s ± 2%   -20.37%  (p=0.000 n=10+10)
DeduplicateSamples/minScrapeInterval=10s-10  7.28GB/s ± 2%  5.48GB/s ± 1%   -24.74%  (p=0.000 n=10+10)
```

https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3333
Signed-off-by: hagen1778 <roman@victoriametrics.com>

Signed-off-by: hagen1778 <roman@victoriametrics.com>
2022-12-08 18:06:11 -08:00
Aliaksandr Valialkin
0d86644d65
lib/storage: leave the last sample per each discrete interval during the deduplicaton
This aligns better with staleness logic in Prometheus - https://prometheus.io/docs/prometheus/latest/querying/basics/#staleness
2022-05-02 21:50:45 +03:00
Aliaksandr Valialkin
4ff647137a
lib/storage: deduplicate samples more thoroughly
Previously some duplicate samples may be left on disk for time series with high churn rate.
This may result in higher disk space usage.
2021-12-15 15:59:58 +02:00
Aliaksandr Valialkin
92070cbb67
lib/storage: return dedup interval in milliseconds from GetDedupInterval()
This removes duplicate .Milliseconds() calls after GetDedupInterval() calls.
2021-12-15 13:26:38 +02:00
Aliaksandr Valialkin
1d20a19c7d
lib/storage: explicitly pass dedupInterval to DeduplicateSamples() and deduplicateSamplesDuringMerge()
This improves the code readability and debuggability, since the output of these functions
stops depending on global state.
2021-12-14 20:49:12 +02:00
Aliaksandr Valialkin
8ca2799478 lib/storage: properly determine when the deduplication is needed in needsDedup
Previously needsDedup() could return true if the de-duplication wasn't needed for the following case:

         d < interval
           /     \
   |        v | v        |
     interval   interval

Now it properly returns false for this case
2021-07-12 10:53:30 +03:00
kreedom
fb967ae6c8 happy fmt 2020-04-26 14:16:32 +03:00
Aliaksandr Valialkin
d7c1ff8b0c lib/storage: improve deduplication algorithm
Now it leaves only the first data point on each `-dedup.minScrapeInterval` interval.

Previously it may leave two data points on the interval. This could lead to unexpected results
for `histogram_quantile(phi, sum(rate(buckets)) by (le))` query.
2020-04-26 13:10:02 +03:00
Aliaksandr Valialkin
ded0c0d3c7 lib/storage: correctly handle -dedup.minScrapeInterval values smaller than 8ms
Such small values may be used for removing samples with duplicate timestamps.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/409 for details.
2020-04-10 16:36:41 +03:00
Aliaksandr Valialkin
c4acd20d2a lib/storage: remove duplicate data points on 7/8*minScrapeInterval interval instead of 1/2*minScrapeInterval
This should reduce storage usage and should improve deduplication accuracy
2020-04-01 15:48:48 +03:00
Aliaksandr Valialkin
18af31a4c2 all: properly split vm_deduplicated_samples_total among cluster components
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/345
2020-02-27 23:48:07 +02:00
Aliaksandr Valialkin
d21cb43e48 lib/storage: add vm_ prefix to deduplicated_samples_total metric to be conistent with other metrics 2020-02-21 19:33:59 +02:00
Aliaksandr Valialkin
e210cd9da1 lib/storage: move -dedup.minScrapeInterval flag outside lib/storage, so it doesnt show up in vminsert in cluster version 2020-02-10 13:09:51 +02:00
Aliaksandr Valialkin
bd4698bb7a lib/storage: do not deduplicate blocks with less than 32 samples during merge
This should improve deduplication accuracy for blocks with higher number of samples.
2020-02-04 18:41:54 +02:00
Aliaksandr Valialkin
42864bb52f all: do not clash flag description with back-quoted flag types
See https://golang.org/pkg/flag/#PrintDefaults for more details.
2020-02-04 15:46:52 +02:00
Aliaksandr Valialkin
c3d86eef96 all: add -dedup.minScrapeInterval command-line flag for data de-duplication
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/86
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/278
2020-01-31 01:16:57 +02:00