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.
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
* port un-synced changed from docs/readme to readme
* consistently use `sh` instead of `console` highlight, as it looks like
a more appropriate syntax highlight
* consistently use `sh` instead of `bash`, as it is shorter
* consistently use `yaml` instead of `yml`
See syntax codes here https://gohugo.io/content-management/syntax-highlighting/
Signed-off-by: hagen1778 <roman@victoriametrics.com>
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>
vmagent: properly add extra labels before sending data to remote storage
labels from `remoteWrite.label` are now added to sent metrics just before they
are pushed to `remoteWrite.url` after all relabelings, including stream aggregation relabelings (#4247)
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4247
Signed-off-by: Alexander Marshalov <_@marshalov.org>
Co-authored-by: Roman Khavronenko <roman@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
