* BUGFIX: properly handle queries containing a filter on metric name plus any number of negative filters and zero non-negative filters. For example, `node_cpu_seconds_total{mode!="idle"}`. The bug was introduced in [v1.54.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.54.0).
* FEATURE: optimize searching for matching metrics for `metric{<label_filters>}` queries if `<label_filters>` contains at least a single filter. For example, the query `up{job="foobar"}` should find the matching time series much faster than previously.
* FEATURE: reduce execution times for `q1 <binary_op> q2` queries by executing `q1` and `q2` in parallel.
* FEATURE: single-node VictoriaMetrics now accepts requests to handlers with `/prometheus` and `/graphite` prefixes such as `/prometheus/api/v1/query`. This improves compatibility with [handlers from VictoriaMetrics cluster](https://victoriametrics.github.io/Cluster-VictoriaMetrics.html#url-format).
* FEATURE: expose `process_open_fds` and `process_max_fds` metrics. These metrics can be used for alerting when `process_open_fds` reaches `process_max_fds`. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/402 and https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1037
* FEATURE: vmalert: add `-datasource.appendTypePrefix` command-line option for querying both Prometheus and Graphite datasource in cluster version of VictoriaMetrics. See [these docs](https://victoriametrics.github.io/vmalert.html#graphite) for details.
* FEATURE: vmauth: add ability to route requests from a single user to multiple destinations depending on the requested paths. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1064
* FEATURE: vmagent: add `__meta_kubernetes_endpoints_label_*`, `__meta_kubernetes_endpoints_labelpresent_*`, `__meta_kubernetes_endpoints_annotation_*` and `__meta_kubernetes_endpoints_annotationpresent_*` labels for `role: endpoints` in Kubernetes service discovery. These labels where added in Prometheus 2.25.
* FEATURE: reduce the minimum supported retention period for inverted index (aka `indexdb`) from one month to one day. This should reduce disk space usage for `<-storageDataPath>/indexdb` folder if `-retentionPeriod` is set to values smaller than one month.
* FEATURE: vmselect: export per-tenant metrics `vm_vmselect_http_requests_total` and `vm_vmselect_http_requests_duration_ms_total` . Other per-tenant metrics are available as a part of [enterprise package](https://victoriametrics.com/enterprise.html). See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/932 for details.
* BUGFIX: properly convert regexp tag filters containing escaped dots to non-regexp tag filters. For example, `{foo=~"bar\.baz"}` should be converted to `{foo="bar.baz"}`. Previously it was incorrectly converted to `{foo="bar\.baz"}`, which could result in missing time series for this tag filter.
* BUGFIX: do not spam error logs when discovering Docker Swarm targets without dedicated IP. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1028 .
* BUGFIX: properly embed timezone data into VictoriaMetrics apps. This should fix `-loggerTimezone` usage inside Docker containers.
* BUGFIX: properly build Docker images for non-amd64 architectures (arm, arm64, ppc64le, 386) on [Docker hub](https://hub.docker.com/u/victoriametrics/). Previously these images were incorrectly based on amd64 base image, so they didn't work.
* BUGFIX: vmagent: return back unsent block to the queue during graceful shutdown. Previously this block could be dropped if remote storage is unavailable during vmagent shutdown. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1065 .
* FEATURE: added [vmctl tool](https://victoriametrics.github.io/vmctl.html) to VictoriaMetrics release process. Now it is packaged in `vmutils-*.tar.gz` archive on [the releases page](https://github.com/VictoriaMetrics/VictoriaMetrics/releases). Source code for `vmctl` tool has been moved from [github.com/VictoriaMetrics/vmctl](https://github.com/VictoriaMetrics/vmctl) to [github.com/VictoriaMetrics/VictoriaMetrics/app/vmctl](https://github.com/VictoriaMetrics/VictoriaMetrics/tree/master/app/vmctl).
* FEATURE: added `-search.maxStepForPointsAdjustment` command-line flag, which can be used for disabling adjustment for points returned by `/api/v1/query_range` handler if such points have timestamps closer than `-search.latencyOffset` to the current time. Such points may contain incomplete data, so they are substituted by the previous values for `step` query args smaller than one minute by default.
* FEATURE: vmselect: added ability to use Graphite-compatible filters in MetricsQL via `{__graphite__="foo.*.bar"}` syntax. This expression is equivalent to `{__name__=~"foo[.][^.]*[.]bar"}`, but it works faster and it is easier to use when migrating from Graphite to VictoriaMetrics. This feature deprecates the usage of `-search.treatDotsAsIsInRegexps` command-line flag.
* FEATURE: vmselect: added ability to set additional label filters, which must be applied during queries. Such label filters can be set via optional `extra_label` query arg, which is accepted by [querying API](https://victoriametrics.github.io/#prometheus-querying-api-usage) handlers. For example, the request to `/api/v1/query_range?extra_label=tenant_id=123&query=<query>` adds `{tenant_id="123"}` label filter to the given `<query>`. It is expected that the `extra_label` query arg is automatically set by auth proxy sitting
in front of VictoriaMetrics. [Contact us](mailto:sales@victoriametrics.com) if you need assistance with such a proxy. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1021 .
* FEATURE: vmalert: added `-datasource.queryStep` command-line flag for passing optional `step` query arg to `/api/v1/query` endpoint. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1025
* FEATURE: vmalert: added ability to query Graphite datasource when evaluating alerting and recording rules. See [these docs](https://victoriametrics.github.io/vmalert.html#graphite) for details.
* FEATURE: vmagent: added `-remoteWrite.roundDigits` command-line option for rounding metric values to the given number of decimal digits after the point before sending the metric to the corresponding `-remoteWrite.url`. This option can be used for improving data compression on the remote storage, because values with lower number of decimal digits can be compressed better than values with bigger number of decimal digits.
* FEATURE: vmagent: added `-remoteWrite.rateLimit` command-line flag for limiting data transfer rate to `-remoteWrite.url`. This may be useful when big amounts of buffered data is sent after temporarily unavailability of the remote storage. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1035
* BUGFIX: vmagent: reduce HTTP reconnection rate for scrape targets. Previously vmagent could errorneusly close HTTP keep-alive connections more frequently than needed.
* BUGFIX: vmagent: retry scrape and service discovery requests when the remote server closes HTTP keep-alive connection. Previously `disable_keepalive: true` option could be used under `scrape_configs` section when working with such servers.
* FEATURE: provide a sample list of alerting rules for VictoriaMetrics components. It is available [here](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/deployment/docker/alerts.yml).
* FEATURE: disable final merge for data for the previous month at the beginning of new month, since it may result in high disk IO and CPU usage. Final merge can be enabled by setting `-finalMergeDelay` command-line flag to positive duration.
* FEATURE: add `tfirst_over_time(m[d])` and `tlast_over_time(m[d])` functions to [MetricsQL](https://victoriametrics.github.io/MetricsQL.html) for returning timestamps for the first and the last data point in `m` over `d` duration.
* FEATURE: add ability to pass multiple labels to `sort_by_label()` and `sort_by_label_desc()` functions. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/992 .
* FEATURE: enforce at least TLS v1.2 when accepting HTTPS requests if `-tls`, `-tlsCertFile` and `-tlsKeyFile` command-line flags are set, because older TLS protocols such as v1.0 and v1.1 have been deprecated due to security vulnerabilities.
* FEATURE: support `extra_label` query arg for all HTTP-based [data ingestion protocols](https://victoriametrics.github.io/#how-to-import-time-series-data). This query arg can be used for specifying extra labels which should be added for the ingested data.
* FEATURE: vmbackup: increase backup chunk size from 128MB to 1GB. This should reduce the number of Object storage API calls during backups by 8x. This may also reduce costs, since object storage API calls usually have non-zero costs. See https://aws.amazon.com/s3/pricing/ and https://cloud.google.com/storage/pricing#operations-pricing .
* BUGFIX: properly parse escaped unicode chars in MetricsQL metric names, label names and function names. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/990
* BUGFIX: vmagent: prevent from `dialing to the given TCP address time out` error when scraping big number of unavailable targets. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/987
* BUGFIX: vmagent: properly log errors when `-promscrape.streamParse` command-line flag is set. See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/1009
* BUGFIX: vmagent: properly suppress errors when both `-promscrape.suppressScrapeErrors` and `-promscrape.streamParse` command-line flags are set. See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/1009 .
* BUGFIX: vmalert: return non-empty result in template func `query` stub to pass validation. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/989 .
* BUGFIX: upgrade base image for Docker packages from Alpine 3.12.1 to Alpine 3.12.3 in order to fix potential security issues. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1010
* FEATURE: add `/api/v1/status/top_queries` handler, which returns the most frequently executed queries and queries that took the most time for execution. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/907
* FEATURE: vmagent: add support for `proxy_url` config option in Prometheus scrape configs. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/503
* FEATURE: remove parts with stale data as soon as they go outside the configured `-retentionPeriod`. Previously such parts may remain active for long periods of time. This should help reducing disk usage for `-retentionPeriod` smaller than one month.
* BUGFIX: vmagent: set missing `__meta_kubernetes_service_*` labels in `kubernetes_sd_config` for `endpoints` and `endpointslices` roles. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/982
* BUGFIX: do not adjust `offset` value provided in MetricsQL query. Previously it could be modified in order to improve response cache hit ratio. This is unneeded, since cache hit ratio should remain good because the query time range should be already aligned to multiple of `step` values. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/976
* FEATURE: do not publish duplicate Docker images with `-cluster` tag suffix for [vmagent](https://victoriametrics.github.io/vmagent.html), [vmalert](https://victoriametrics.github.io/vmalert.html), [vmauth](https://victoriametrics.github.io/vmauth.html), [vmbackup](https://victoriametrics.github.io/vmbackup.html) and [vmrestore](https://victoriametrics.github.io/vmrestore.html), since they are identical to images without `-cluster` tag suffix.
* BUGFIX: vmalert: properly populate template variables. This has been broken in v1.50.0. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/974
* BUGFIX: properly parse negative combined duration in MetricsQL such as `-1h3m4s`. It must be parsed as `-(1h + 3m + 4s)`. Prevsiously it was parsed as `-1h + 3m + 4s`.
* BUGFIX: properly parse lines in [Prometheus exposition format](https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md) and in [OpenMetrics format](https://github.com/OpenObservability/OpenMetrics/blob/master/specification/OpenMetrics.md) with whitespace after the timestamp. For example, `foo 123 456 # some comment here`. See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/970
* BUGFIX: vmagent: properly delete unregistered scrape targets from `/targets` and `/api/v1/targets` pages. They weren't deleted due to the bug in `v1.50.0`.
* FEATURE: automatically reset response cache when samples with timestamps older than `now - search.cacheTimestampOffset` are ingested to VictoriaMetrics. This makes unnecessary disabling response cache during data backfilling or resetting it after backfilling is complete as described [in these docs](https://victoriametrics.github.io/#backfilling). This feature applies only to single-node VictoriaMetrics. It doesn't apply to cluster version of VictoriaMetrics because `vminsert` nodes don't know about `vmselect` nodes where the response cache must be reset.
* FEATURE: vmagent: return user-friendly HTML page when requesting `/targets` page from web browser. The page is returned in the old plaintext format when requesting via curl or similar tool.
* FEATURE: allow multiple whitespace chars between measurements, fields and timestamp when parsing InfluxDB line protocol.
Though [InfluxDB line protocol](https://docs.influxdata.com/influxdb/v1.8/write_protocols/line_protocol_tutorial/) denies multiple whitespace chars between these entities,
some apps improperly put multiple whitespace chars. This workaround allows accepting data from such apps.
* FEATURE: export `vm_promscrape_scrapers_started_total{type="<sd_type>"}` and `vm_promscrape_scrapers_stopped_total{type="<sd_type>"}` metrics for tracking churn rate for scrapers
* BUGFIX: properly handle `*` and `[...]` inside curly braces in query passed to Graphite Metrics API. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/952
* BUGFIX: vmagent: fix memory leak when big number of targets is discovered via service discovery.
* BUGFIX: vmagent: properly pass `datacenter` filter to Consul API server. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/574#issuecomment-740454170
* BUGFIX: properly handle CPU limits set on the host system or host container. The bugfix may result in lower memory usage on systems with CPU limits. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/946
* BUGFIX: prevent from duplicate `name` tag returned from `/tags/autoComplete/tags` handler. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/942
* BUGFIX: do not enable strict parsing for `-promscrape.config` if `-promscrape.config.dryRun` comand-line flag is set. Strict parsing can be enabled with `-promscrape.config.strictParse` command-line flag. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/944
* BUGFIX: vmagent: properly handle scrape errors when stream parsing is enabled with `-promscrape.streamParse` command-line flag or with `stream_parse: true` per-target config option. Previously such errors weren't reported at `/targets` page. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/967
* BUGFIX: assume the previous value is 0 when calculating `increase()` for the first point on the graph if its value doesn't exceed 100 and the delta between two first points equals to 0. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/962
* FEATURE: optimize Consul service discovery speed when discovering big number of services. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/574
* FEATURE: add `label_uppercase(q, label1, ... labelN)` and `label_lowercase(q, label1, ... labelN)` function to [MetricsQL](https://victoriametrics.github.io/MetricsQL.html)
for uppercasing and lowercasing values for the given labels. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/936
* FEATURE: add `count_eq_over_time(m[d], N)` and `count_ne_over_time(m[d], N)` for counting the number of samples for `m` over `d` that (equal / not equal) to `N`.
* FEATURE: do not print usage info for all the command-line flags when incorrect command-line flag is passed. Previously it could be hard reading the error message
about incorrect command-line flag because of too big usage info for all the flags.
* FEATURE: upgrade Go builder from v1.15.5 to v1.15.6 . This fixes [issues found in Go since v1.15.5](https://github.com/golang/go/issues?q=milestone%3AGo1.15.6+label%3ACherryPickApproved).
* BUGFIX: properly parse timestamps in OpenMetrics format - they are exposed as floating-point number in seconds instead of integer milliseconds
unlike in Prometheus exposition format. See [the docs](https://github.com/OpenObservability/OpenMetrics/blob/master/specification/OpenMetrics.md#timestamps).
* BUGFIX: return `nan` for `a >bool b` query when `a` equals to `nan` like Prometheus does. Previously `0` was returned in this case. This applies to any comparison operation
with `bool` modifier. See [these docs](https://prometheus.io/docs/prometheus/latest/querying/operators/#comparison-binary-operators) for details.
* BUGFIX: handle `time() cmp_op metric` like Prometheus does - i.e. return `metric` value if `cmp_op` comparison is true. Previously `time()` value was returned.
* BUGFIX: return `nan` for `minute(m)` query when `m` equals to `nan` like Prometheus does. This applies to all the time-related functions such as `day_of_month`, `day_of_week`,
* FEATURE: added [Snap package for single-node VictoriaMetrics](https://snapcraft.io/victoriametrics). This simplifies installation under Ubuntu to a single command:
* FEATURE: vminsert: export `vm_rpc_vmstorage_is_reachable` metric, which can be used for monitoring reachability of vmstorage nodes from vminsert nodes.
* FEATURE: add `-loggerWarnsPerSecondLimit` command-line flag for rate limiting of WARN messages in logs. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/905
* FEATURE: apply `loggerErrorsPerSecondLimit` and `-loggerWarnsPerSecondLimit` rate limit per caller. I.e. log messages are suppressed if the same caller logs the same message
at the rate exceeding the given limit. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/905#issuecomment-729395855
* FEATURE: log metric name plus all its labels when the metric timestamp is out of the configured retention. This should simplify detecting the source of metrics with unexpected timestamps.
* BUGFIX: properly parse Prometheus metrics with [exemplars](https://github.com/OpenObservability/OpenMetrics/blob/master/OpenMetrics.md#exemplars-1) such as `foo 123 # {bar="baz"} 1`.
* FEATURE: vmselect: return the original error from `vmstorage` node in query response if `-search.denyPartialResponse` is set.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/891
* FEATURE: vmselect: add `"isPartial":{true|false}` field in JSON output for `/api/v1/*` functions
from [Prometheus querying API](https://prometheus.io/docs/prometheus/latest/querying/api/). `"isPartial":true` is set if the response contains partial data
because of a part of `vmstorage` nodes were unavailable during query processing.
* FEATURE: vmagent: reduce memory usage when service discovery detects big number of scrape targets and the set of discovered targets changes over time.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/825
* FEATURE: vmagent: add `-promscrape.dropOriginalLabels` command-line option, which can be used for reducing memory usage when scraping big number of targets.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/825#issuecomment-724308361 for details.
* FEATURE: add `-search.treatDotsAsIsInRegexps` command-line flag, which can be used for automatic escaping of dots in regexp label filters used in queries.
For example, if `-search.treatDotsAsIsInRegexps` is set, then the query `foo{bar=~"aaa.bb.cc|dd.eee"}` is automatically converted to `foo{bar=~"aaa\\.bb\\.cc|dd\\.eee"}`.
* FEATURE: update Go builder from v1.15.4 to v1.15.5. This should fix [these issues in Go](https://github.com/golang/go/issues?q=milestone%3AGo1.15.5+label%3ACherryPickApproved).
* BUGFIX: remove spikes at the end of time series gaps for `increase()` or `delta()` functions. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/894
* BUGFIX: vminsert: properly return HTTP 503 status code when all the vmstorage nodes are unavailable. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/896
* FEATURE: vmagent: reduce memory usage when `kubernetes_sd_config` discovers big number of scrape targets (e.g. hundreds of thousands) and the majority of these targets (99%)
are dropped during relabeling. Previously labels for all the dropped targets were displayed at `/api/v1/targets` page. Now only up to `-promscrape.maxDroppedTargets` such
targets are displayed. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/878 for details.
* BUGFIX: vmagent: eliminate data race when `-promscrape.streamParse` command-line is set. Previously this mode could result in scraped metrics with garbage labels.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/825#issuecomment-723198247 for details.
* BUGFIX: properly calculate `topk_*` and `bottomk_*` functions from [MetricsQL](https://victoriametrics.github.io/MetricsQL.html) for time series with gaps.
See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/883
* FEATURE: allow setting `-retentionPeriod` smaller than one month. I.e. `-retentionPeriod=3d`, `-retentionPeriod=2w`, etc. is supported now.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/173
* FEATURE: optimize more cases according to https://utcc.utoronto.ca/~cks/space/blog/sysadmin/PrometheusLabelNonOptimization . Now the following cases are optimized too:
*`rollup_func(foo{filters}[d]) op bar` -> `rollup_func(foo{filters}[d]) op bar{filters}`
*`transform_func(foo{filters}) op bar` -> `transform_func(foo{filters}) op bar{filters}`
*`num_or_scalar op foo{filters} op bar` -> `num_or_scalar op foo{filters} op bar{filters}`
* FEATURE: improve time series search for queries with multiple label filters. I.e. `foo{label1="value", label2=~"regexp"}`.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/781
* FEATURE: vmagent: add `stream parse` mode. This mode allows reducing memory usage when individual scrape targets expose tens of millions of metrics.
For example, during scraping Prometheus in [federation](https://prometheus.io/docs/prometheus/latest/federation/) mode.
See `-promscrape.streamParse` command-line option and `stream_parse: true` config option for `scrape_config` section in `-promscrape.config`.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/825 and [troubleshooting docs for vmagent](https://victoriametrics.github.io/vmagent.html#troubleshooting).
* FEATURE: vmalert: add `-dryRun` command-line option for validating the provided config files without the need to start `vmalert` service.
* FEATURE: accept optional third argument of string type at `topk_*` and `bottomk_*` functions. This is label name for additional time series to return with the sum of time series outside top/bottom K. See [MetricsQL docs](https://victoriametrics.github.io/MetricsQL.html) for more details.
* FEATURE: vmagent: expose `/api/v1/targets` page according to [the corresponding Prometheus API](https://prometheus.io/docs/prometheus/latest/querying/api/#targets).
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/643
* BUGFIX: vmagent: properly handle OpenStack endpoint ending with `v3.0` such as `https://ostack.example.com:5000/v3.0`
in the same way as Prometheus does. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/728#issuecomment-709914803
* BUGFIX: drop trailing data points for time series with a single raw sample. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/748
* BUGFIX: do not drop trailing data points for instant queries to `/api/v1/query`. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/845
* BUGFIX: vmbackup: fix panic when `-origin` isn't specified. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/856
* BUGFIX: vmalert: skip automatically added labels on alerts restore. Label `alertgroup` was introduced in [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/611)
and automatically added to generated time series. By mistake, this new label wasn't correctly purged on restore event and affected alert's ID uniqueness.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/870
* BUGFIX: vmagent: fix panic at scrape error body formating. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/864
* BUGFIX: vmagent: add leading missing slash to metrics path like Prometheus does. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/835
* BUGFIX: vmagent: drop packet if remote storage returns 4xx status code. This make the behaviour consistent with Prometheus.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/873
* BUGFIX: vmagent: properly handle 301 redirects. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/869
* FEATURE: automatically add missing label filters to binary operands as described at https://utcc.utoronto.ca/~cks/space/blog/sysadmin/PrometheusLabelNonOptimization .
This should improve performance for queries with missing label filters in binary operands. For example, the following query should work faster now, because it shouldn't
fetch and discard time series for `node_filesystem_files_free` metric without matching labels for the left side of the expression:
* FEATURE: vmagent: add Docker Swarm service discovery (aka [dockerswarm_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#dockerswarm_sd_config)).
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/656
* FEATURE: add ability to export data in CSV format. See [these docs](https://victoriametrics.github.io/#how-to-export-csv-data) for details.
* FEATURE: vmagent: add `-promscrape.suppressDuplicateScrapeTargetErrors` command-line flag for suppressing `duplicate scrape target` errors.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/651 and https://victoriametrics.github.io/vmagent.html#troubleshooting .
* FEATURE: vmagent: show original labels before relabeling is applied on `duplicate scrape target` errors. This should simplify debugging for incorrect relabeling.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/651
* FEATURE: vmagent: `/targets` page now accepts optional `show_original_labels=1` query arg for displaying original labels for each target before relabeling is applied.
This should simplify debugging for target relabeling configs. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/651
* FEATURE: add `-finalMergeDelay` command-line flag for configuring the delay before final merge for per-month partitions.
The final merge is started after no new data is ingested into per-month partition during `-finalMergeDelay`.
* FEATURE: add `vm_rows_added_to_storage_total` metric, which shows the total number of rows added to storage since app start.
The `sum(rate(vm_rows_added_to_storage_total))` can be smaller than `sum(rate(vm_rows_inserted_total))` if certain metrics are dropped
due to [relabeling](https://victoriametrics.github.io/#relabeling). The `sum(rate(vm_rows_added_to_storage_total))` can be bigger
than `sum(rate(vm_rows_inserted_total))` if [replication](https://victoriametrics.github.io/Cluster-VictoriaMetrics.html#replication-and-data-safety) is enabled.
* FEATURE: keep metric name after applying [MetricsQL](https://victoriametrics.github.io/MetricsQL.html) functions, which don't change time series meaning.
The list of such functions:
*`keep_last_value`
*`keep_next_value`
*`interpolate`
*`running_min`
*`running_max`
*`running_avg`
*`range_min`
*`range_max`
*`range_avg`
*`range_first`
*`range_last`
*`range_quantile`
*`smooth_exponential`
*`ceil`
*`floor`
*`round`
*`clamp_min`
*`clamp_max`
*`max_over_time`
*`min_over_time`
*`avg_over_time`
*`quantile_over_time`
*`mode_over_time`
*`geomean_over_time`
*`holt_winters`
*`predict_linear`
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/674
* BUGFIX: properly handle stale time series after K8S deployment. Previously such time series could be double-counted.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/748
* BUGFIX: return a single time series at max from `absent()` function like Prometheus does.
* BUGFIX: vmalert: accept days, weeks and years in `for: ` part of config like Prometheus does. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/817
* BUGFIX: fix `mode_over_time(m[d])` calculations. Previously the function could return incorrect results.
* FEATURE: reduce CPU usage for repeated queries over sliding time window when no new time series are added to the database.
Typical use cases: repeated evaluation of alerting rules in [vmalert](https://victoriametrics.github.io/vmalert.html) or dashboard auto-refresh in Grafana.
* FEATURE: vmagent: add OpenStack service discovery aka [openstack_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#openstack_sd_config).
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/728 .
* FEATURE: vmalert: make `-maxIdleConnections` configurable for datasource HTTP client. This option can be used for minimizing connection churn.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/795 .
* FEATURE: add `-influx.maxLineSize` command-line flag for configuring the maximum size for a single Influx line during parsing.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/807
* BUGFIX: properly handle `inf` values during [background merge of LSM parts](https://medium.com/@valyala/how-victoriametrics-makes-instant-snapshots-for-multi-terabyte-time-series-data-e1f3fb0e0282).
Previously `Inf` values could result in `NaN` values for adjancent samples in time series. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/805 .
* BUGFIX: fill gaps on graphs for `range_*` and `running_*` functions. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/806 .
* BUGFIX: make a copy of label with new name during relabeling with `action: labelmap` in the same way as Prometheus does.
Previously the original label name has been replaced. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/812 .
* BUGFIX: support parsing floating-point timestamp like Graphite Carbon does. Such timestmaps are truncated to seconds.
* FEATURE: use all the available CPU cores when accepting data via a single TCP connection
for [all the supported protocols](https://victoriametrics.github.io/#how-to-import-time-series-data).
Previously data ingested via a single TCP connection could use only a single CPU core. This could limit data ingestion performance.
The main benefit of this feature is that data can be imported at max speed via a single connection - there is no need to open multiple concurrent
connections to VictoriaMetrics or [vmagent](https://victoriametrics.github.io/vmagent.html) in order to achieve the maximum data ingestion speed.
* FEATURE: cluster: improve performance for data ingestion path from `vminsert` to `vmstorage` nodes. The maximum data ingestion performance
for a single connection between `vminsert` and `vmstorage` node scales with the number of available CPU cores on `vmstorage` side.
This should help with https://github.com/VictoriaMetrics/VictoriaMetrics/issues/791 .
* FEATURE: add ability to export / import data in native format via `/api/v1/export/native` and `/api/v1/import/native`.
This is the most optimized approach for data migration between VictoriaMetrics instances. Both single-node and cluster instances are supported.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/787#issuecomment-700632551 .
* FEATURE: add `reduce_mem_usage` query option to `/api/v1/export` in order to reduce memory usage during data export / import.
See [these docs](https://victoriametrics.github.io/#how-to-export-data-in-json-line-format) for details.
* FEATURE: improve performance for `/api/v1/series` handler when it returns big number of time series.
* FEATURE: add `vm_merge_need_free_disk_space` metric, which can be used for estimating the number of deferred background data merges due to the lack of free disk space.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/686 .
* FEATURE: add OpenBSD support. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/785 .
* BUGFIX: properly apply `-search.maxStalenessInterval` command-line flag value. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/784 .
* BUGFIX: fix displaying data in Grafana tables. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/720 .
* BUGFIX: do not adjust the number of detected CPU cores found at `/sys/devices/system/cpu/online`.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/685#issuecomment-698595309 .
* BUGFIX: vmagent: do not show `-remoteWrite.url` in initial logs if `-remoteWrite.showURL` isn't set. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/773 .
* BUGFIX: properly handle case when [/metrics/find](https://victoriametrics.github.io/#graphite-metrics-api-usage) finds both a leaf and a node for the given `query=prefix.*`.
In this case only the node must be returned with stripped dot in the end of id as carbonapi does.
# Previous releases
See [releases page](https://github.com/VictoriaMetrics/VictoriaMetrics/releases).
