This is a follow-up for 43b24164ef
* lib/fs: adds memory map for windows
it should improve performance for file reading
* lib/storage: replace '/' with os specific separator
it must fix an errors for windows
* lib/fs: mention windows fsync support
* lib/filestream: adds fdatasync for windows writes
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/70
* allowed using dashes and dots in environment variables names for templating config files with envtemplate (#3999)
Signed-off-by: Alexander Marshalov <_@marshalov.org>
* Apply suggestions from code review
---------
Signed-off-by: Alexander Marshalov <_@marshalov.org>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* lib/netutil: log only parsing errors for proxy-protocol
Previosly every error was logged. With configured TCP health checks at load-balancer or kubernetes, vmauth spams a lot of false positive error message into logs
* Update docs/CHANGELOG.md
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
* Update lib/netutil/tcplistener.go
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
---------
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
This commit changes background merge algorithm, so it becomes compatible with Windows file semantics.
The previous algorithm for background merge:
1. Merge source parts into a destination part inside tmp directory.
2. Create a file in txn directory with instructions on how to atomically
swap source parts with the destination part.
3. Perform instructions from the file.
4. Delete the file with instructions.
This algorithm guarantees that either source parts or destination part
is visible in the partition after unclean shutdown at any step above,
since the remaining files with instructions is replayed on the next restart,
after that the remaining contents of the tmp directory is deleted.
Unfortunately this algorithm doesn't work under Windows because
it disallows removing and moving files, which are in use.
So the new algorithm for background merge has been implemented:
1. Merge source parts into a destination part inside the partition directory itself.
E.g. now the partition directory may contain both complete and incomplete parts.
2. Atomically update the parts.json file with the new list of parts after the merge,
e.g. remove the source parts from the list and add the destination part to the list
before storing it to parts.json file.
3. Remove the source parts from disk when they are no longer used.
This algorithm guarantees that either source parts or destination part
is visible in the partition after unclean shutdown at any step above,
since incomplete partitions from step 1 or old source parts from step 3 are removed
on the next startup by inspecting parts.json file.
This algorithm should work under Windows, since it doesn't remove or move files in use.
This algorithm has also the following benefits:
- It should work better for NFS.
- It fits object storage semantics.
The new algorithm changes data storage format, so it is impossible to downgrade
to the previous versions of VictoriaMetrics after upgrading to this algorithm.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3236
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3821
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/70
lib{mergset,storage}: prevent possible race condition with logging stats for merges
Previously partwrapper could be release by background process and reference for part may be invalid
during logging stats. It will lead to panic at vmstorage
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3897
- Use flag.Duration instead of flagutil.Duration for -snapshotCreateTimeout,
since the flagutil.Duration is intended mostly for big durations, e.g. days, months and years,
while the -snapshotCreateTimeout is usually smaller than one hour.
- Add links to https://docs.victoriametrics.com/#how-to-work-with-snapshots in docs/CHANGELOG.md,
so readers could easily find the corresponding docs when reading the changelog.
- Properly remove all the created directories on unsuccessful attempt to create
snapshot in Storage.CreateSnapshot().
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3551
* lib/{fs,mergeset,storage}: skip `.must-remove.` dirs when creating snapshot (#3858)
* lib/{mergeset,storage}: add timeout configuration for snapshots creation, remove incomplete snapshots from storage
* docs: fix formatting
* app/vmstorage: add metrics to track status of snapshots
* app/vmstorage: use `vm_http_requests_total` metric for snapshot endpoints metrics, rename new flag to make name more clear
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* app/vmstorage: update flag name in docs
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* app/vmstorage: reflect new metrics names change in docs
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
---------
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* lib/promscrape: set `vm_promscrape_config_last_reload_successful` to 1 if there was no promscrape config provided
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* lib/promscrape: register `vm_promscrape_config_*` metrics only in case promscrape config is used
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
---------
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
- Return immediately on context cancel during the backoff sleep.
This should help with https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3747
- Add a comment describing why the second attempt to obtain the response from remote side
is perfromed immediately after the first attempt.
- Remove fasthttp dependency from lib/promscrape/discoveryutils
- Set context deadline before calling doRequestWithPossibleRetry().
This simplifies the doRequestWithPossibleRetry() a bit.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3293
* fix: do not use exponential backoff for first retry of scrape request (#3293)
* lib/promscrape: refactor `doRequestWithPossibleRetry` backoff to simplify logic
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* Update lib/promscrape/client.go
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
* lib/promscrape: refactor `doRequestWithPossibleRetry` to make it more straightforward
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
---------
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
* Modify API version when running in Container App
* Handle expires on from token response
Response from IMDS does not always contain expires in value which is
currently used to get the token expiry time. An example resources that
doesn't provide it are Container Apps and App Service.
Signed-off-by: Mattias Ängehov <mattias.angehov@castoredc.com>
* Fix client id parameter for user assigned identity
* Apply suggestions from code review
---------
Signed-off-by: Mattias Ängehov <mattias.angehov@castoredc.com>
Co-authored-by: Aliaksandr Valialkin <valyala@gmail.com>
- Do not generate __meta_server label, since it is unavailable in Prometheus.
- Add a link to https://docs.victoriametrics.com/sd_configs.html#kuma_sd_configs to docs/CHANGELOG.md,
so users could click it and read the docs without the need to search the corresponding docs.
- Remove kumaTarget struct, since it is easier generating labels for discovered targets
directly from the response returned by Kuma. This simplifies the code.
- Store the generated labels for discovered targets inside atomic.Value. This allows reading them
from concurrent goroutines without the need to use mutex.
- Use synchronouse requests to Kuma instead of long polling, since there is a little sense
in the long polling when the Kuma server may return 304 Not Modified response every -promscrape.kumaSDCheckInterval.
- Remove -promscrape.kuma.waitTime command-line flag, since it is no longer needed when long polling isn't used.
- Set default value for -promscrape.kumaSDCheckInterval to 30s in order to be consistent with Prometheus.
- Remove unnecessary indirections for string literals, which are used only once, in order to improve code readability.
- Remove unused fields from discoveryRequest and discoveryResponse.
- Update tests.
- Document why fetch_timeout and refresh_interval options are missing in kuma_sd_config.
- Add docs to discoveryutils.RequestCallback and discoveryutils.ResponseCallback,
since these are public types.
Side notes: it is weird that Prometheus implementation for kuma_sd_configs sets `instance` label,
since usually this label is set by the Prometheus itself to __address__ after the relabeling phase.
See https://www.robustperception.io/life-of-a-label/
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3389
See https://github.com/prometheus/prometheus/issues/7919
and https://github.com/prometheus/prometheus/pull/8844
as a reference implementation in Prometheus
`lib/protoparser/prometheus` is used by various applications,
such as `app/vmalert`. The recent change to the
`lib/protoparser/prometheus` package introduced a new dependency
of `lib/writeconcurrencylimiter` which exposes some metrics.
Because of the dependency, now all applications which have this
dependency also expose these metrics.
Creating a new `lib/protoparser/prometheus/stream` package helps
to remove these metrics from apps which use `lib/protoparser/prometheus`
as dependency.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3761
Signed-off-by: hagen1778 <roman@victoriametrics.com>
previously historical data backfilling may trigger force merge for previous month every hour
it consumes cpu, disk io and decrease cluster performance.
Following commit fixes it by applying deduplication for InMemoryParts
The limit has been increased from 300 bytes to 500 bytes according to the collected production stats.
This allows reducing CPU usage without significant increase of RAM usage in most practical cases.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3692
Switch to the actual API version `2016-11-15`,
since the old version doesn't provide access to all
the fields which implementation expects.
For example, old API missing `zone_id` field
in `DescribeAvailabilityZonesResponse` response.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3700
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Allow users fine-tuning the maximum string length for interning via -internStringMaxLen command-line flag.
This may be used for fine-tuning RAM vs CPU usage for certain workloads.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3692
- Call httpserver.GetQuotedRemoteAddr() and httpserver.GetRequestURI() only when the error occurs.
This saves CPU time on fast path when there are no parsing errors.
- Create a helper function - httpserver.LogError() - for logging the error with the request uri and remote addr context.
Stale series are sent when there is a difference between current
and previous scrapes. Those series which disappeared in the current scrape
are marked as stale and sent to the remote storage.
Sending stale series requires memory allocation and in case when too many
series disappear in the same it could result in noticeable memory spike.
For example, re-deploy of a big fleet of service can result into
excessive memory usage for vmagent, because all the series with old
pod name will be marked as stale and sent to the remote write storage.
This change limits the number of stale series which can be sent at once,
so memory usage remains steady.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3668https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3675
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
This prevents vmbackup from leaking passwords into logs like shown below.
2023-01-11T15:00:01.050Z info VictoriaMetrics/lib/logger/flag.go:12 build version: vmbackup-20221214-211706-tags-v1.85.1-0-g09a70d3e9
2023-01-11T15:00:01.050Z info VictoriaMetrics/lib/logger/flag.go:13 command-line flags
2023-01-11T15:00:01.050Z info VictoriaMetrics/lib/logger/flag.go:20 -dst="fs:///vm-backups/latest"
2023-01-11T15:00:01.050Z info VictoriaMetrics/lib/logger/flag.go:20 -snapshot.createURL="http://user:super_sercret123@victoriametricspshot/create"
2023-01-11T15:00:01.050Z info VictoriaMetrics/lib/logger/flag.go:20 -storageDataPath="/storage"
2023-01-11T15:00:01.050Z info VictoriaMetrics/app/vmbackup/main.go:53 Snapshot create url http://user:super_sercret123@victoriametrics:8428/snapshot/create
2023-01-11T15:00:01.050Z info VictoriaMetrics/app/vmbackup/main.go:60 Snapshot delete url http://user:super_sercret123@victoriametrics:8428/snapshot/delete
Assisted merges are intended to be performed by goroutines, which accept the incoming samples,
in order to limit the data ingestion rate.
The worker, which converts pending samples to parts, shouldn't be penalized by assisted merges,
since this may result in increased number of pending rows as seen at https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3647#issuecomment-1385039142
when the assisted merge takes too much time.
- Document the fix at docs/CHANGELOG.md
- Limit the concurrency for sendStaleMarkers() function in order to limit its memory usage
when big number of targets disappear and staleness markers are sent
for all the metrics exposed by these targets.
- Make sure that the writeRequestCtx is returned to the pool
when there is no need to send staleness markers.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3668
- Add a comment describing the purpose of the `role` field inside `apiConfig` struct
- Revert changes at lib/promscrape/discovery/dockerswarm/dockerswarm.go ,
since they reduce code readability. E.g. the reader needs to look up the named string constants
in order to get their values.
* {lib/server, app/}: use `httpAuth.*` flag as fallback for `*AuthKey` if it is not set
* lib/ingestserver/opentsdbhttp: fix opentdb HTTP handler not respecting `httpAuth.*` flags
* Apply suggestions from code review
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
- Use promutils.Labels.GetLabels() instead of comparing promutils.Labels.Labels to nil.
This make the code more consistent with other places.
- Mention the release where the issue has been introduced at docs/CHANGELOG.md.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3624
See the list of configs supported by Prometheus at f88a0a7d83/discovery/nomad/nomad.go (L76-L84)
- Removed "token" option. In can be set either via NOMAD_TOKEN env var or via `bearer_token` config option.
- Removed "scheme" option. It is automatically detected depending on whether the `tls_config` is set.
- Removed "services" and "tags" options, since they aren't supported by Prometheus.
- Added "region" option. If it is missing, then the region is read from NOMAD_REGION env var.
If this var is empty, then it is set to "global" in the same way as Nomad client does.
See 865ee8d37c/api/api.go (L297)
and 865ee8d37c/api/api.go (L555-L556)
- If the "server" option is missing, then it is read from NOMAD_ADDR in the same way
as Nomad client does - see 865ee8d37c/api/api.go (L294-L296)
This is a follow-up for 8aee209c53
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3367
This should reduce the maximum memory usage for processScrapedData() function by 2x.
The only part, which can be IO-bound in the processScrapedData() is pushData() call,
when it buffers data to persistent queue if the remote storage cannot keep up
with the data ingestion speed. In this case it is OK if the scrape pace will be limited.
This should reduce memory usage when scraping big number of targets,
since this limits the summary memory usage during concurrent parsing and relabeling
by the number of available CPU cores.
Previously the -maxConcurrentInserts was limiting the number of established client connections,
which write data to VictoriaMetrics. Some of these connections could be idle.
Such connections do not consume big amounts of CPU and RAM, so there is a little sense in limiting
the number of such connections. So now the -maxConcurrentInserts command-line option
limits the number of concurrently executed insert requests, not including idle connections.
It is recommended removing -maxConcurrentInserts command-line option, since the default value
for this option should work good for most cases.
- Document the bugfix at docs/CHANGELOG.md
- Wait until all the worker goroutines are done in consulWatcher.mustStop()
- Do not log `context canceled` errors when discovering consul serviceNames
- Removed explicit handling of gzipped responses at lib/promscrape/discoveryutils.Client,
since this handling is automatically performed by net/http.Transport.
See DisableCompression option at https://pkg.go.dev/net/http#Transport .
- Remove explicit handling of the proxyURL, since it is automatically handled
by net/http.Transport. See Proxy option at https://pkg.go.dev/net/http#Transport .
- Expliticly set MaxIdleConnsPerHost, since its default value equals to 2.
Such a small value may result in excess tcp connection churn
when more than 2 concurrent requests are processed by lib/promscrape/discoveryutils.Client.
- Do not set explicitly the `Host` request header, since it is automatically set by net/http.Client.
- Backport the bugfix to the recently added nomad_sd_configs - see https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3367
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3468
- Remove undocumented `username` and `password` config options from `nomad_sd_config`.
TODO: probably, remove these options from `consul_sd_config` too?
These options exist there for backwards compatibility purposes.
- Add __meta_nomad_service_alloc_id and __meta_nomad_service_job_id meta-labels
These labels contain AllocID and JobID fields for the discovered Nomad services.
- Various typo fixes.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3367
Before, if the imported line contained multiple metrics and one
or more of them had an empty values - the whole line was ignored.
Now, only metrics with empty values are ignored, and the rest
of the metrics are accepted successfully.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3540
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
Use "unexpected status code returned from %q: %d; expecting %d" log message format
instead of less clear format "unexpected status code returned from %q; expecting %d; got %d"
This is a follow-up for c612bb165e
* app/vmbackupmanager: add metrics for better observability, include more information to `/api/v1/backups` API call response
* app/vmbackupmanager: drop old metrics before creating new ones
* app/vmbackupmanager: use `_total` postfix for counter metrics
* app/vmbackupmanager: remove `_total` postfix for gauge-like metrics
* app/vmbackupmanager: add `_last_run_failed` metrics for backups and retention
* app/vmbackupmanager: address review feedback
* app/vmbackupmanager: fix metric name
* app/vmbackupmanager: address review feedback, remove background updates of metrics, add restoring state of `_last_run_failed` metric from remote storage
* app/vmbackupmanager: improve performance for backup size calculation
* app/vmbackupmanager: refactor backup and retention runs to deduplicate each run logic
* {app/vmbackupmanager,lib/formatutil}: move HumanizeBytes into lib package
* app/vmbackupmanager: fix creating new metrics instead of reusing existing ones
* lit/formatutil: add comment to make linter happy
* app/vmbackupmanager: address review feedback
The issue triggers after the indexdb rotation for time series, which stop receiving new samples.
This results in missing data for such time series in query responses.
This commit should address the https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3502
The issue has been introduced in 2dd93449d8
- Document the change at docs/CHANELOG.md
- Log fatal errors if the -loggerJSONFields contains unexpected values
- Rename -loggerJsonFields to -loggerJSONFields for the sake of consistency naming commonly used in Go
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2348
This fixes handling of values bigger than 2GiB for the following command-line flags:
- -storage.minFreeDiskSpaceBytes
- -remoteWrite.maxDiskUsagePerURL
Blocked small merges may result into big number of small parts, which, in turn,
may result in increased CPU and memory usage during queries, since queries need to inspect
all the existing small parts.
The issue has been introduced in 8189770c50
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3337
Previously only up to 100K results were cached.
This could result in sub-optimal performance when more than 100K unique strings were actually used.
For example, when the relabeling rule was applied to a million of unique Graphite metric names
like in the https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3466
This commit should reduce the long-term CPU usage for https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3466
after all the unique Graphite metrics are registered in the FastStringMatcher.Transform() cache.
It is expected that the number of unique strings, which are passed to FastStringMatcher.Match(),
FastStringTransformer.Transform() and to InternString() during the last 5 minutes,
is limited, so the function results fit memory. Otherwise OOM crash can occur.
This should be the case for typical production workloads.
* lib/promscrape/discovery/azure: remove API server from URL returned by azure
* lib/promscrape/discovery/azure: validate nextLink contains same URL as apiServer
This should simplify further debugging, since the first thing to start the debugging by query trace
is to know the version of VictoriaMetrics, which produced this trace.
The main purpose of this command-line flag is to increase the lifetime of low-end flash storage
with the limited number of write operations it can perform. Such flash storage is usually
installed on Raspberry PI or similar appliances.
For example, `-inmemoryDataFlushInterval=1h` reduces the frequency of disk write operations
to up to once per hour if the ingested one-hour worth of data fits the limit for in-memory data.
The in-memory data is searchable in the same way as the data stored on disk.
VictoriaMetrics automatically flushes the in-memory data to disk on graceful shutdown via SIGINT signal.
The in-memory data is lost on unclean shutdown (hardware power loss, OOM crash, SIGKILL).
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3337
- Return meta-labels for the discovered targets via promutils.Labels
instead of map[string]string. This improves the speed of generating
meta-labels for discovered targets by up to 5x.
- Remove memory allocations in hot paths during ScrapeWork generation.
The ScrapeWork contains scrape settings for a single discovered target.
This improves the service discovery speed by up to 2x.
It has been appeared that some production workloads could suffer for some time
after every reset of the previous cache when it gets less than 5% of requests
after the needed item isn't found in the current cache. This could result
in reduced cache hit rates, which, in turn, could increase CPU, disk IO and RAM
usage needed for reading, unpacking and caching the missed data from disk.
This commit reduces the cache miss threshold for resetting the previous cache from 5% to 1%.
This should reduce the possible negative impact after each cache reset by at least 5x,
while reducing the total memory used by caches.
This is a follow-up for d906d8573e
The issue was in the `labels := dst[offset:]` line in the beginning of appendExtraLabels() function.
The `dst` may be re-allocated when adding extra labels to it. In this case the addition of `exported_`
prefix to labels inside `labels` slice become invisible in the returned `dst` labels.
While at it, properly handle some corner cases:
- Add additional `exported_` prefix to clashing metric labels with already existing `exported_` prefix.
- Store scraped metric names in `exported___name__` label if scrape target contains `__name__` label.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3278
Thanks to @jplanckeel for the initial attempt to fix this issue
at https://github.com/VictoriaMetrics/VictoriaMetrics/pull/3281
Previously netstorage.MustStop() call didn't free up all the resources,
so the subsequent call to nestorage.Init() would panic.
This allows writing tests, which call nestorage.Init() + nestorage.MustStop() in a loop.
Blocks outside the configured retention are eventually deleted during background merge.
But such blocks may reside in the storage for long time until background merge.
Previously VictoriaMetrics could spend additional CPU time on processing such blocks
during search queries. Now these blocks are skipped.
The searchTSIDs function was searching for metricIDs matching the the given tag filters
and then was locating the corresponding TSID entries for the found metricIDs.
The TSID entries aren't needed when searching for time series names (aka MetricName),
so this commit removes the uneeded TSID search from the implementation of /api/v1/series API.
This improves perfromance of /api/v1/series calls.
This commit also improves performance a bit for /api/v1/query and /api/v1/query_range calls,
since now these calls cache small metricIDs instead of big TSID entries
in the indexdb/tagFilters cache (now this cache is named indexdb/tagFiltersToMetricIDs)
without the need to compress the saved entries in order to save cache space.
This commit also removes concurrency limiter during searching for matching time series,
which was introduced in 8f16388428, since the concurrency
for all the read queries is already limited with -search.maxConcurrentRequests command-line flag.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/648
This increases the maximum time for cache population with new entries from 20 minutes to 40 minutes.
This
This change shouldn't increase memory usage for caches, since the prev cache cleaner
should free up memory by deleting unused prev cache as soon as possible.
See 08ca45d238 for details on prev cache cleaner.
The panic has been introduced in 68f3a02589
While at it, add padding to shard structs in order to avoid false sharing on mordern CPUs
This should improve scalability on systems with many CPU cores
This means that the majority of requests are successfully served from the current cache,
so the previous cache can be reset in order to free up memory.
