Stream aggregation may yield inaccurate results if it processes incomplete data.
This issue can arise when data is sourced from clients that maintain a queue of unsent data, such as Prometheus or vmagent.
If the queue isn't fully cleared within the aggregation interval, only a portion of the time series may be included in that period, leading to distorted calculations.
To mitigate this we add an option to ignore first N aggregation intervals. It is expected, that client queues
will be cleared during the time while aggregation ignores first N intervals and all subsequent aggregations
will be correct.
This reverts commit eb40395a1c.
Reason for revert: it has been appeared that the performance gain on multiple CPU cores
wasn't visible because the benchmark was generating incorrect pushSample.key.
See a207e0bf687d65f5198207477248d70c69284296
Previously samples were dropped on the first incomplete interval and the next complete interval.
Also make sure that the de-duplication is performed just before flushing the aggregate state.
This should help the case then dedup_interval = interval.
For example, if `interval: 1m`, then data flush occurs at the end of every minute,
while `interval: 1h` leads to data flush at the end of every hour.
Add `no_align_flush_to_interval` option, which can be used for disabling the alignment.
- Reduce memory usage by up to 5x when de-duplicating samples across big number of time series.
- Reduce memory usage by up to 5x when aggregating across big number of output time series.
- Add lib/promutils.LabelsCompressor, which is going to be used by other VictoriaMetrics components
for reducing memory usage for marshaled []prompbmarshal.Label.
- Add `dedup_interval` option at aggregation config, which allows setting individual
deduplication intervals per each aggregation.
- Add `keep_metric_names` option at aggregation config, which allows keeping the original
metric names in the output samples.
- Add `unique_samples` output, which counts the number of unique sample values.
- Add `increase_prometheus` and `total_prometheus` outputs, which ignore the first sample
per each newly encountered time series.
- Use 64-bit hashes instead of marshaled labels as map keys when calculating `count_series` output.
This makes obsolete https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5579
- Expose various metrics, which may help debugging stream aggregation:
- vm_streamaggr_dedup_state_size_bytes - the size of data structures responsible for deduplication
- vm_streamaggr_dedup_state_items_count - the number of items in the deduplication data structures
- vm_streamaggr_labels_compressor_size_bytes - the size of labels compressor data structures
- vm_streamaggr_labels_compressor_items_count - the number of entries in the labels compressor
- vm_streamaggr_flush_duration_seconds - a histogram, which shows the duration of stream aggregation flushes
- vm_streamaggr_dedup_flush_duration_seconds - a histogram, which shows the duration of deduplication flushes
- vm_streamaggr_flush_timeouts_total - counter for timed out stream aggregation flushes,
which took longer than the configured interval
- vm_streamaggr_dedup_flush_timeouts_total - counter for timed out deduplication flushes,
which took longer than the configured dedup_interval
- Actualize docs/stream-aggregation.md
The memory usage reduction increases CPU usage during stream aggregation by up to 30%.
This commit is based on https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5850
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5898
Sending unfinished aggregate states tend to produce unexpected anomalies with lower values than expected.
The old behavior can be restored by specifying `flush_on_shutdown: true` setting in streaming aggregation config
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Examples:
1) -metricsAuthKey=file:///abs/path/to/file - reads flag value from the given absolute filepath
2) -metricsAuthKey=file://./relative/path/to/file - reads flag value from the given relative filepath
3) -metricsAuthKey=http://some-host/some/path?query_arg=abc - reads flag value from the given url
The flag value is automatically updated when the file contents changes.
* lib/streamaggr: properly reference slice with labels
by limiting slice capacity. It must fix issues with slice modification, in case of append new slice will be allocated, instead of modifying refrenced slice
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5402
* Reduce memory allocations when output_relabel_configs adds new labels to output samples
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Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
- Use a byte slice instead of a map for tracking indexes for matching series.
This improves performance, since access by slice index is faster than access by map key.
- Re-use the byte slice for tracking indexes for matching series.
This removes unnecessary memory allocations and improves stream aggregation performance a bit.
- Add an ability to return to the previous behvaiour by specifying -remoteWrite.streamAggr.dropInput command-line flag.
In this case all the input samples are dropped when stream aggregation is enabled.
- Backport the new stream aggregation behaviour from vmagent to single-node VictoriaMetrics when -streamAggr.config
option is set.
- Improve docs regarding this change at docs/CHANGELOG.md
- Document the new behavior at docs/stream-aggregation.md
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4243
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4575
* {lib/streamaggr,vmagent/remotewrite}: breaking change for keepInput flag
Changes default behaviour of keepInput flag to write series which did not match any aggregators to the remote write.
See: https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4243
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* Update app/vmagent/remotewrite/remotewrite.go
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
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Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
Previously all the incoming samples were de-duplicated, even if their series doesn't
match aggregation rule filters. This could result in increased CPU usage.
Now the de-duplication isn't applied to samples for series, which do not match
aggregation rule filters. Such samples are just ignored.
- Round staleness_interval durations to the upper number of seconds.
This should prevent from under-calculations for fractional staleness intervals.
- Rename stalenessInterval field at *AggrState structs into stalenessSecs, since it holds seconds.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4667
This reverts commit 9e99f2f5b3.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4068
Reason for revert: this breaks valid use cases:
- If timestamps aren't specified in the incoming samples on purpose. For example, if stream aggregation is used
as StatsD replacement. StatsD protocol has no timestamp concept for incoming samples.
See https://github.com/b/statsd_spec
- If all the samples must be aggregated, even if they contain stale timestamps.
for example, if the stream aggregation produces some counter of some events,
it may be better to count all the events even if they were delayed before
being ingested into VictoriaMetrics.
Is is also unclear how to determine whether the sample becomes stale.
For example, if the aggregation interval equals to 1h, and the previous
aggregation cycle just finished 10 minutes ago, what to do with the newly
incoming sample with the timestamp 30 minutes older than the current time?
The answer highly depends on the context, so it is unsafe to uncoditionally
use a single logic for dropping the old samples here.
* lib/streamaggr: discard samples with timestamps not matching aggregation interval
Samples with timestamps lower than `now - aggregation_interval` are likely to be written via backfilling and should not be used for calculation of aggregation.
See #4068
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* lib/streamaggr: make log message more descriptive, fix imports
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
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Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
