Instead, log a sample of these long items once per 5 seconds into error log,
so users could notice and fix the issue with too long labels or too many labels.
Previously this panic could occur in production when ingesting samples with too long labels.
The 3c246cdf00 added an optimization where the previous metaindexRow
could be saved to disk when the current block header couldn't be added indexBlock because the resulting
indexBlock size became too big. This could result in an empty metaindexRow.firstItem for the next metaindexRow.
This allows removing importing unneeded command-line flags into binaries, which import lib/storage,
which, in turn, was importing lib/snapshot in order to use Time, Validate and NewName functions.
This is a follow-up for 83e55456e2
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5738
Closing client connections every 2 minutes doesn't help load balancing -
this just leads to "jumpy" connections between multiple backend servers,
e.g. the load isn't spread evenly among backend servers, and instead jumps
between the servers every 2 minutes.
It is still possible periodically closing client connections by specifying non-zero -http.connTimeout command-line flag.
This should help with https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1304#issuecomment-1636997037
This is a follow-up for d387da142e
There is no sense in storing commonPrefix for blockHeader containing only a single item,
since this only increases blockHeader size without any benefits.
This panic could occur when samples with too long label values are ingested into VictoriaMetrics.
This could result in too long fistItem and commonPrefix values at blockHeader (up to 64kb each).
This may inflate the maximum index block size by 4 * maxIndexBlockSize.
For example, -fooDuration=',10s,' is now supported - it sets three command-line flag values:
- the first and the last one are set to the default value for `-fooDuration`
- the second one is set to 10s
This should significantly reduce the number of open ReaderAt files
on VictoriaMetrics and VictoriaLogs startup.
The open files can be tracked via vm_fs_readers metric
GOGC can be already set via environment variable. There is no need in adding
new approaches for setting the GOGC (such as command-line flag), since they complicate operations.
Remove temporary file before closing it in order to signal the OS that it shouldn't
store the file contents from page cache to disk when the file is closed.
Gracefully handle the case when the file cannot be removed before being closed -
in this case remove the file after closing it. This allows working on Windows.
Also remove superflouos opening of temporary file for reading - re-use already opened file handle for writing.
This is a follow-up for 9b1e002287
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4020
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/70
The easyproto-based marshaler is 2x slower than the previous custom marshaler,
so let's stick with it. This improves the performance for sending data to remote storage at vmagent
and reduces CPU usage to pre-v1.97.0 levels.
* adding support for username_file in basic_auth of scrape config
Signed-off-by: Syed Nihal <syed.nihal@nokia.com>
* adding support for username_file in basic_auth of scrape config. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5511
Signed-off-by: Syed Nihal <syed.nihal@nokia.com>
* adding support for username_file in basic_auth of scrape config
Signed-off-by: Syed Nihal <syed.nihal@nokia.com>
* adding support for username_file in basic_auth of scrape config
Signed-off-by: Syed Nihal <syed.nihal@nokia.com>
* adding support for username_file in basic_auth of scrape config
Signed-off-by: Syed Nihal <syed.nihal@nokia.com>
---------
Signed-off-by: Syed Nihal <syed.nihal@nokia.com>
Entries for the previous dates is usually not used, so there is little sense in keeping them in memory.
This should reduce the size of storage/date_metricID cache, which can be monitored
via vm_cache_entries{type="storage/date_metricID"} metric.
This limit has little sense for these APIs, since:
- Thses APIs frequently result in scanning of all the time series on the given time range.
For example, if extra_filters={datacenter="some_dc"} .
- Users expect these APIs shouldn't hit the -search.maxUniqueTimeseries limit,
which is intended for limiting resource usage at /api/v1/query and /api/v1/query_range requests.
Also limit the concurrency for /api/v1/labels, /api/v1/label/.../values
and /api/v1/series requests in order to limit the maximum memory usage and CPU usage for these API.
This limit shouldn't affect typical use cases for these APIs:
- Grafana dashboard load when dashboard labels should be loaded
- Auto-suggestion list load when editing the query in Grafana or vmui
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5055
* Optimize the performance of data merge: decimal.CalibrateScale() from 49633 ns/op to 9146 ns/op
* Optimize the performance of data merge: decimal.CalibrateScale()
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>
- Maintain a separate worker pool per each part type (in-memory, file, big and small).
Previously a shared pool was used for merging all the part types.
A single merge worker could merge parts with mixed types at once. For example,
it could merge simultaneously an in-memory part plus a big file part.
Such a merge could take hours for big file part. During the duration of this merge
the in-memory part was pinned in memory and couldn't be persisted to disk
under the configured -inmemoryDataFlushInterval .
Another common issue, which could happen when parts with mixed types are merged,
is uncontrolled growth of in-memory parts or small parts when all the merge workers
were busy with merging big files. Such growth could lead to significant performance
degradataion for queries, since every query needs to check ever growing list of parts.
This could also slow down the registration of new time series, since VictoriaMetrics
searches for the internal series_id in the indexdb for every new time series.
The third issue is graceful shutdown duration, which could be very long when a background
merge is running on in-memory parts plus big file parts. This merge couldn't be interrupted,
since it merges in-memory parts.
A separate pool of merge workers per every part type elegantly resolves both issues:
- In-memory parts are merged to file-based parts in a timely manner, since the maximum
size of in-memory parts is limited.
- Long-running merges for big parts do not block merges for in-memory parts and small parts.
- Graceful shutdown duration is now limited by the time needed for flushing in-memory parts to files.
Merging for file parts is instantly canceled on graceful shutdown now.
- Deprecate -smallMergeConcurrency command-line flag, since the new background merge algorithm
should automatically self-tune according to the number of available CPU cores.
- Deprecate -finalMergeDelay command-line flag, since it wasn't working correctly.
It is better to run forced merge when needed - https://docs.victoriametrics.com/#forced-merge
- Tune the number of shards for pending rows and items before the data goes to in-memory parts
and becomes visible for search. This improves the maximum data ingestion rate and the maximum rate
for registration of new time series. This should reduce the duration of data ingestion slowdown
in VictoriaMetrics cluster on e.g. re-routing events, when some of vmstorage nodes become temporarily
unavailable.
- Prevent from possible "sync: WaitGroup misuse" panic on graceful shutdown.
This is a follow-up for fa566c68a6 .
Thanks @misutoth to for the inspiration at https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5212
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5190
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3790
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3551
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3337
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3425
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3647
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3641
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/648
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/291
The maxFileParts usage has been accidentally removed in fa566c68a6
While at it, add Count suffix to *AssistedMerges counter names in order to make them less misleading.
Previously their names were falsely suggesting that these are gauges, which show the number of concurrently
executed assisted merges.
It has been appeared that the registration of new time series slows down linearly
with the number of indexdb parts, since VictoriaMetrics needs to check every indexdb part
when it searches for TSID by newly ingested metric name.
The number of in-memory parts grows when new time series are registered
at high rate. The number of in-memory parts grows faster on systems with big number
of CPU cores, because the mergeset maintains per-CPU buffers with newly added entries
for the indexdb, and every such entry is transformed eventually into a separate in-memory part.
The solution has been suggested in https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5212
by @misutoth - to limit the number of in-memory parts with buffered channel.
This solution is implemented in this commit. Additionally, this commit merges per-CPU parts
into a single part before adding it to the list of in-memory parts. This reduces CPU load
when searching for TSID by newly ingested metric name.
The https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5212 recommends setting the limit on the number
of in-memory parts to 100, but my internal testing shows that much lower limit 15 works with the same efficiency
on a system with 16 CPU cores while reducing memory usage for `indexdb/dataBlocks` cache by up to 50%.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5190
This allows reducing the indexdb/tagFiltersToMetricIDs cache size by 8 on average.
The cache size can be checked via vm_cache_size_bytes{type="indexdb/tagFiltersToMetricIDs"} metric exposed at /metrics page.
Measuring read / write duration from / to in-memory buffers has little sense,
since it will be always fast. It is better to measure read / write duration from / to
real files at vm_filestream_write_duration_seconds_total and vm_filestream_read_duration_seconds_total metrics.
This also reduces overhead on time.Now() and Histogram.UpdateDuration() calls
per each filestream.Reader.Read() and filestream.Writer.Write() call when the data is read / written from / to in-memory buffers.
This is a follow-up for 2f63dec2e3
* lib/promscrape: respect `0` value for `series_limit` param
Respect `0` value for `series_limit` param in `scrape_config`
even if global limit was set via `-promscrape.seriesLimitPerTarget`.
Previously, `0` value will be ignored in favor of `-promscrape.seriesLimitPerTarget`.
This behavior aligns with possibility to override `series_limit` value via
relabeling with `__series_limit__` label.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* Update docs/CHANGELOG.md
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
This should smooth CPU and RAM usage spikes related to these periodic tasks,
by reducing the probability that multiple concurrent periodic tasks are performed at the same time.
The dateMetricIDCache puts recently registered (date, metricID) entries into mutable cache protected by the mutex.
The dateMetricIDCache.Has() checks for the entry in the mutable cache when it isn't found in the immutable cache.
Access to the mutable cache is protected by the mutex. This means this access is slow on systems with many CPU cores.
The mutabe cache was merged into immutable cache every 10 seconds in order to avoid slow access to mutable cache.
This means that ingestion of new time series to VictoriaMetrics could result in significant slowdown for up to 10 seconds
because of bottleneck at the mutex.
Fix this by merging the mutable cache into immutable cache after len(cacheItems) / 2
cache hits under the mutex, e.g. when the entry is found in the mutable cache.
This should automatically adjust intervals between merges depending on the addition rate
for new time series (aka churn rate):
- The interval will be much smaller than 10 seconds under high churn rate.
This should reduce the mutex contention for mutable cache.
- The interval will be bigger than 10 seconds under low churn rate.
This should reduce the uneeded work on merging of mutable cache into immutable cache.
* lib/promscrape/discovery/kubernetes: fix watcher start order for roles endpoints and endpointslice
Previously the groupWatcher could be mistakenly stopped when requests for pod or services resources take too long.
* remove mislead comment
* docs/sd_configs.md: mention -promscrape.kubernetes.attachNodeMetadataAll flag in the description for attach_metadata section
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4640
* wip
* lib/promscrape/kubernetes: prevent from stopping groupWatcher when there are in-flight apiWatcher.mustStart() calls
groupWatcher is stopped if it has zero registered apiWatchers during 14 seconds.
But such a groupWatcher can be still in use if apiWatcher for `role: endpoints` or `role: endpointslice`
is being registered and the discovery of the associated `pod` and/or `service` objects takes longer
than 14 seconds - see the beginning of groupWatcher.startWatchersForRole() function for details.
Track the number of in-flight calls to apiWatcher.mustStart() and prevent from stopping the associated groupWatcher
if the number of in-flight calls is non-zero.
P.S. postponing the discovery of `pod` and/or `service` objects associated with `endpoints` or `endpointslice` roles
isn't the best solution, since it slows down initial discovery of `endpoints` and `endpointslice` targets.
* typo fix
---------
Co-authored-by: Aliaksandr Valialkin <valyala@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.
- docs/sd_configs.md: moved hetzner_sd_configs docs to the correct place according to alphabetical order of SD names,
document missing __meta_hetzner_role label.
- lib/promscrape/config.go: added missing MustStop() call for Hetzner SD,
and moved the code to the correct place according to alphabetical order of SD names.
- lib/promscrape/discovery/hetzner: properly handle pagination for hloud API responses,
populate missing __meta_hetzner_role label like Prometheus does.
- Properly populate __meta_hetzner_public_ipv6_network label like Prometheus does.
- Remove unused SDConfig.Token.
- Remove "omitempty" annotation from SDConfig.Role field, since this field is mandatory.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5550
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3154
- Clarify the bugfix description at docs/CHANGELOG.md
- Simplify the code by accessing prefetchedMetricIDs struct under the lock
instead of using lockless access to immutable struct.
This shouldn't worsen code scalability too much on busy systems with many CPU cores,
since the code executed under the lock is quite small and fast.
This allows removing cloning of prefetchedMetricIDs struct every time
new metric names are pre-fetched. This should reduce load on Go GC,
since the cloning of uin64set.Set struct allocates many new objects.
Before, this cache was limited only by size.
Cache invalidation by time happens with jitter to prevent thundering herd problem.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
The user may which to control the endpoint parameters for instance to
set the audience when requesting an access token. Exposing the
parameters as a map allows for additional use cases without requiring
modification.
* lib/awsapi: properly assume role with webIdentity token
introduce new irsaRoleArn param for config. It's only needed for authorization with webIdentity token.
First credentials obtained with irsa role and the next sts assume call for an actual roleArn made with those credentials.
Common use case for it - cross AWS accounts authorization
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3822
* wip
---------
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
Some clients may ingest samples via OpenTelemetry protocol without Resource labels.
Previously VictoriaMetrics was silently dropping such samples.
The commit 317834f876 added vm_protoparser_rows_dropped_total{type="opentelemetry",reason="resource_not_set"}
counter for tracking of such dropped samples. See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5459
It is better from usability PoV to accept such samples instead of dropping them and incrementing the corresponding counter.
Currently, it is impossible to understand why metrics are not ingested when resource is not set by OTEL exporter. Adding metric should simplify debugging and make it improve debuggability.
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
* fix typos in docs
* add `shard-` prefix to generated links when `-promscrape.cluster.memberURLTemplate` is enabled
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmagent: export `vm_promscrape_scrape_pool_targets` metric to track the number of targets that each scrape_job discovers
* add extra panel for new metric
- Add links to relevant docs into descriptions for every -kafka.* and -gcp.pubsub.* command-line flags.
- Wait until message processing goroutines are stopped before returning from gcppubsub.Stop().
- Prevent from multiple calls to Init() without Stop().
- Drop message if tenantID cannot be parsed properly.
- Take into account tenantID for all the supported message formats.
- Support gzip-compressed messages for graphite format.
- Use exponential backoff sleep when the message cannot be pushed to remote storage systems
because of disabled on-disk persistence - https://docs.victoriametrics.com/vmagent.html#disabling-on-disk-persistence
- Unblock from sleep as soon as Stop() is called. Previously the sleep could take up to 2 seconds after Stop() is called.
- Remove unused globalCtx and initContext from app/vmagent/remotewrite/gcppubsub
- Mention Google PubSub support at docs/enterprise.md
- Make Google PubSub docs more clear at docs/vmagent.md
This is a follow-up for commits 115245924a5f096c5a3383d6cc8e8b6fbd421984
and e6eab781ce42285a6a1750dc01eba6801dd35516 .
Updates https://github.com/VictoriaMetrics/VictoriaMetrics-enterprise/pull/717
Updates https://github.com/VictoriaMetrics/VictoriaMetrics-enterprise/pull/713
E.g. replace `fs.Dir + filePath` with `path.Join(fs.Dir, filePath)`
The fs.Dir is guaranteed to end with slash - see Init() functions.
The filePath may start with slash. If it starts with slash, then `fs.Dir + filePath` constructs
an incorrect path with double slashes.
path.Join() properly substitutes duplicate slashes with a single slash in this case.
While at it, also substitute incorrect usage of filepath.Join() with path.Join()
for constructing paths to object storage systems, which expect forward slashes in paths.
filepath.Join() substittues forward slashes with backslashes on Windows, so this may break
creating or managing backups from Windows.
This is a follow-up for 0399367be602b577baf6a872ca81bf0f99ba401b
Updates https://github.com/VictoriaMetrics/VictoriaMetrics-enterprise/pull/719
Previously the /service-discovery page didn't show targets dropped because of sharding
( https://docs.victoriametrics.com/vmagent.html#scraping-big-number-of-targets ).
Show also the reason why every target is dropped at /service-discovery page.
This should improve debuging why particular targets are dropped.
While at it, do not remove dropped targets from the list at /service-discovery page
until the total number of targets exceeds the limit passed to -promscrape.maxDroppedTargets .
Previously the list was cleaned up every 10 minutes from the entries, which weren't updated
for the last minute. This could complicate debugging of dropped targets.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5389
* 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
---------
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* prevent /api/v1 from panic on parsing rows
* add tests for Extract function for v1 and v2 api's
* separate request types in different pools to prevent different objects mixing
* add changelog line
543f218fe9
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Andrew Chubatiuk <andrew.chubatiuk@motional.com>
Co-authored-by: Nikolay <https://github.com/f41gh7>
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
- Add Try* prefix to functions, which return bool result in order to improve readability and reduce the probability of missing check
for the result returned from these functions.
- Call the adjustSampleValues() only once on input samples. Previously it was called on every attempt to flush data to peristent queue.
- Properly restore the initial state of WriteRequest passed to tryPushWriteRequest() before returning from this function
after unsuccessful push to persistent queue. Previously a part of WriteRequest samples may be lost in such case.
- Add -remoteWrite.dropSamplesOnOverload command-line flag, which can be used for dropping incoming samples instead
of returning 429 Too Many Requests error to the client when -remoteWrite.disableOnDiskQueue is set and the remote storage
cannot keep up with the data ingestion rate.
- Add vmagent_remotewrite_samples_dropped_total metric, which counts the number of dropped samples.
- Add vmagent_remotewrite_push_failures_total metric, which counts the number of unsuccessful attempts to push
data to persistent queue when -remoteWrite.disableOnDiskQueue is set.
- Remove vmagent_remotewrite_aggregation_metrics_dropped_total and vm_promscrape_push_samples_dropped_total metrics,
because they are replaced with vmagent_remotewrite_samples_dropped_total metric.
- Update 'Disabling on-disk persistence' docs at docs/vmagent.md
- Update stale comments in the code
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5088
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2110
* app/vmagent: allow to disabled on-disk queue
Previously, it wasn't possible to build data processing pipeline with a
chain of vmagents. In case when remoteWrite for the last vmagent in the
chain wasn't accessible, it persisted data only when it has enough disk
capacity. If disk queue is full, it started to silently drop ingested
metrics.
New flags allows to disable on-disk persistent and immediatly return an
error if remoteWrite is not accessible anymore. It blocks any writes and
notify client, that data ingestion isn't possible.
Main use case for this feature - use external queue such as kafka for
data persistence.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2110
* adds test, updates readme
* apply review suggestions
* update docs for vmagent
* makes linter happy
---------
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
Tests showed that importing a single line with 70MB size takes 5.3GiB
RSS memory for VictoriaMetrics single-node.
In the scenario when user exports and imports data from one VM to another,
it could possibly lead to OOM exception for destination VM.
Importing a single line with 16MB size taks 1.3GiB RSS memory.
Hence, the limit for `import.maxLineLen` was decreased from 100MB to 10MB
to improve reliability of VictoriaMetrics during imports.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
This case is possible after the following steps:
1. vmagent successfully performed handshake with the -remoteWrite.url and the remote storage supports zstd-compressed data.
2. remote storage became unavailable or slow to ingest data, vmagent compressed the collected data into blocks with zstd and puts these blocks to persistent queue on disk.
3. vmagent restarts and the remote storage is unavailable during the handshake, then vmagent falls back to Snappy compression.
4. vmagent starts sending zstd-compressed data from persistent queue to the remote storage, while falsely advertizing it sends Snappy-compressed data.
5. The remote storage receives zstd-compressed data and fails unpacking it with Snappy.
The solution is the same as 12cd32fd75, just fall back to zstd decompression if Snappy decompression fails.
* lib/querytracer: makes package concurrent safe to use
it must fix various issues with concurrent code usage.
Especially, when it's not reasonable to wait for all goroutines to be finished
* wip
---------
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* app/vmstorage: close vminsert connections gradually before stopping storage
Implements graceful shutdown approach suggested here - https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4922#issuecomment-1768146878
Test results for this can be found here - https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4922#issuecomment-1790640274
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* app/vmstorage: update graceful shutdown logic
- close connections from vminsert in determenistic order
- update flag description
- lower default timeout to 25 seconds. 25 seconds value was chosen because the lowest default value used in default configuration deployments is 30s(default value in Kubernetes and ansible-playbooks).
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* docs/cluster: add information about re-routing enhancement during restart
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* docs/changelog: add entry for new command-line flag
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* {app/vmstorage,lib/ingestserver}: address review feedback
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* docs/cluster: add note to update workload scheduler timeout
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* wip
---------
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
This case is possible after the following steps:
1. vmagent tries to perform handshake with the -remoteWrite.url in order to determine whether
the remote storage supports zstd-compressed data.
2. The remote storage is unavailable during the handshake. In this case vmagent falls back to Snappy compression
for the data sent to the remote storage.
3. vmagent compresses the collected data into blocks with Snappy and puts these blocks to persistent queue on disk.
4. The remote storage becomes available.
5. vmagent restarts, performs the handshake with the remote storage and detects that it supports zstd-compressed data.
6. vmagent starts sending Snappy-compressed data from persistent queue to the remote storage,
while falsely advertizing it sends zstd-compressed data.
7. The remote storage receives Snappy-compressed data and fails unpacking it with zstd.
The solution is to just fall back to Snappy decompression if zstd decompression fails.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5301
