Merge branch 'master' into issue-11324-2

Signed-off-by: JAYICE <1185430411@qq.com>

README.md

@@ -1,6 +1,6 @@
 # VictoriaMetrics
 
-[![Latest Release](https://img.shields.io/github/v/release/VictoriaMetrics/VictoriaMetrics?sort=semver&label=&filter=!*-victorialogs&logo=github&labelColor=gray&color=gray&link=https%3A%2F%2Fgithub.com%2FVictoriaMetrics%2FVictoriaMetrics%2Freleases%2Flatest)](https://github.com/VictoriaMetrics/VictoriaMetrics/releases)
+[![Latest Release](https://img.shields.io/github/v/release/VictoriaMetrics/VictoriaMetrics?logo=github&labelColor=gray&color=gray&label=Release)](https://github.com/VictoriaMetrics/VictoriaMetrics/releases)
 [![Docker Pulls](https://img.shields.io/docker/pulls/victoriametrics/victoria-metrics?label=&logo=docker&logoColor=white&labelColor=2496ED&color=2496ED&link=https%3A%2F%2Fhub.docker.com%2Fr%2Fvictoriametrics%2Fvictoria-metrics)](https://hub.docker.com/u/victoriametrics)
 [![Build Status](https://github.com/VictoriaMetrics/VictoriaMetrics/actions/workflows/build.yml/badge.svg?branch=master&link=https%3A%2F%2Fgithub.com%2FVictoriaMetrics%2FVictoriaMetrics%2Factions)](https://github.com/VictoriaMetrics/VictoriaMetrics/actions/workflows/build.yml)
 [![License](https://img.shields.io/github/license/VictoriaMetrics/VictoriaMetrics?labelColor=green&label=&link=https%3A%2F%2Fgithub.com%2FVictoriaMetrics%2FVictoriaMetrics%2Fblob%2Fmaster%2FLICENSE)](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/LICENSE)

app/victoria-metrics/main.go

@@ -13,6 +13,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect"
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/promql"
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmstorage"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/appmetrics"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/buildinfo"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/envflag"
@@ -34,9 +35,10 @@ var (
 		"This can be changed with -promscrape.config.strictParse=false command-line flag")
 	maxIngestionRate = flag.Int("maxIngestionRate", 0, "The maximum number of samples vmsingle can receive per second. Data ingestion is paused when the limit is exceeded. "+
 		"By default there are no limits on samples ingestion rate.")
-	vmselectMaxConcurrentRequests = flag.Int("search.maxConcurrentRequests", getDefaultMaxConcurrentRequests(), "The maximum number of concurrent search requests. "+
-		"It shouldn't be high, since a single request can saturate all the CPU cores, while many concurrently executed requests may require high amounts of memory. "+
-		"See also -search.maxQueueDuration and -search.maxMemoryPerQuery")
+	vmselectMaxConcurrentRequests = flagutil.NewIntWithDynamicDefault("search.maxConcurrentRequests", getDefaultMaxConcurrentRequests(), "vmselect.getDefaultMaxConcurrentRequests()",
+		"The maximum number of concurrent search requests. "+
+			"It shouldn't be high, since a single request can saturate all the CPU cores, while many concurrently executed requests may require high amounts of memory. "+
+			"See also -search.maxQueueDuration and -search.maxMemoryPerQuery")
 	vmselectMaxQueueDuration = flag.Duration("search.maxQueueDuration", 10*time.Second, "The maximum time the request waits for execution when -search.maxConcurrentRequests "+
 		"limit is reached; see also -search.maxQueryDuration")
 )
@@ -90,7 +92,9 @@ func main() {
 	}
 	logger.Infof("starting VictoriaMetrics at %q...", listenAddrs)
 	startTime := time.Now()
+
 	vmstorage.Init(*vmselectMaxConcurrentRequests, *vmselectMaxQueueDuration, promql.ResetRollupResultCacheIfNeeded)
+	appmetrics.MustCreateUncleanShutdownMarker(vmstorage.DataPath())
 	vmselect.Init(*vmselectMaxConcurrentRequests, *vmselectMaxQueueDuration)
 	vminsertcommon.StartIngestionRateLimiter(*maxIngestionRate)
 	vminsert.Init()
@@ -120,6 +124,7 @@ func main() {
 
 	vmstorage.Stop()
 	vmselect.Stop()
+	appmetrics.MustRemoveUncleanShutdownMarker(vmstorage.DataPath())
 
 	logger.Infof("the VictoriaMetrics has been stopped in %.3f seconds", time.Since(startTime).Seconds())
 }

app/vmagent/remotewrite/remotewrite.go

@@ -15,6 +15,7 @@ import (
 	"github.com/VictoriaMetrics/metrics"
 	"github.com/cespare/xxhash/v2"
 
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/appmetrics"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/auth"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/bloomfilter"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
@@ -62,9 +63,10 @@ var (
 		"See also -remoteWrite.maxDiskUsagePerURL and -remoteWrite.disableOnDiskQueue")
 	keepDanglingQueues = flag.Bool("remoteWrite.keepDanglingQueues", false, "Keep persistent queues contents at -remoteWrite.tmpDataPath in case there are no matching -remoteWrite.url. "+
 		"Useful when -remoteWrite.url is changed temporarily and persistent queue files will be needed later on.")
-	queues = flagutil.NewArrayInt("remoteWrite.queues", cgroup.AvailableCPUs()*2, "The number of concurrent queues to each -remoteWrite.url. Set more queues if default number of queues "+
-		"isn't enough for sending high volume of collected data to remote storage. "+
-		"Default value depends on the number of available CPU cores. It should work fine in most cases since it minimizes resource usage")
+	queues = flagutil.NewArrayIntWithDynamicDefault("remoteWrite.queues", cgroup.AvailableCPUs()*2, "2*cgroup.AvailableCPUs()",
+		"The number of concurrent queues to each -remoteWrite.url. Set more queues if default number of queues "+
+			"isn't enough for sending high volume of collected data to remote storage. "+
+			"Default value depends on the number of available CPU cores. It should work fine in most cases since it minimizes resource usage")
 	inmemoryQueues = flagutil.NewArrayInt("remoteWrite.inmemoryQueues", 0, "The number of additional workers per each -remoteWrite.url, which send only recently ingested data from the in-memory queue, "+
 		"while the file-based queue at -remoteWrite.tmpDataPath is drained by workers configured via -remoteWrite.queues. "+
 		"This reduces delivery lag for fresh samples when the file-based queue contains a backlog accumulated during remote storage outages.")
@@ -233,6 +235,7 @@ func Init() {
 	initStreamAggrConfigGlobal()
 
 	initRemoteWriteCtxs(*remoteWriteURLs)
+	appmetrics.MustCreateUncleanShutdownMarker(*tmpDataPath)
 
 	disableOnDiskQueues := []bool(*disableOnDiskQueue)
 	disableOnDiskQueueAny = slices.Contains(disableOnDiskQueues, true)
@@ -391,6 +394,8 @@ func Stop() {
 	if sl := dailySeriesLimiter; sl != nil {
 		sl.MustStop()
 	}
+
+	appmetrics.MustRemoveUncleanShutdownMarker(*tmpDataPath)
 }
 
 // PushDropSamplesOnFailure pushes wr to the configured remote storage systems set via -remoteWrite.url

app/vmalert/remotewrite/init.go

@@ -36,9 +36,10 @@ var (
 	idleConnectionTimeout = flag.Duration("remoteWrite.idleConnTimeout", 50*time.Second, `Defines a duration for idle (keep-alive connections) to exist. Consider settings this value less to the value of "-http.idleConnTimeout". It must prevent possible "write: broken pipe" and "read: connection reset by peer" errors.`)
 	maxIdleConnections    = flag.Int("remoteWrite.maxIdleConnections", 100, `Defines the number of idle (keep-alive connections) to -remoteWrite.url for the vmalert-tool debug writer, which sends every series in a separate request. Too low a value may result in a high number of sockets in TIME_WAIT state.`)
 
-	maxQueueSize  = flag.Int("remoteWrite.maxQueueSize", defaultMaxQueueSize, "Defines the max number of pending datapoints to remote write endpoint")
-	maxBatchSize  = flag.Int("remoteWrite.maxBatchSize", defaultMaxBatchSize, "Defines max number of timeseries to be flushed at once")
-	concurrency   = flag.Int("remoteWrite.concurrency", defaultConcurrency, "Defines number of writers for concurrent writing into remote write endpoint. Default value depends on the number of available CPU cores.")
+	maxQueueSize = flag.Int("remoteWrite.maxQueueSize", defaultMaxQueueSize, "Defines the max number of pending datapoints to remote write endpoint")
+	maxBatchSize = flag.Int("remoteWrite.maxBatchSize", defaultMaxBatchSize, "Defines max number of timeseries to be flushed at once")
+	concurrency  = flagutil.NewIntWithDynamicDefault("remoteWrite.concurrency", defaultConcurrency, "2*cgroup.AvailableCPUs()",
+		"Defines number of writers for concurrent writing into remote write endpoint. Default value depends on the number of available CPU cores.")
 	flushInterval = flag.Duration("remoteWrite.flushInterval", defaultFlushInterval, "Defines interval of flushes to remote write endpoint")
 
 	tlsInsecureSkipVerify = flag.Bool("remoteWrite.tlsInsecureSkipVerify", false, "Whether to skip tls verification when connecting to -remoteWrite.url")

app/vmselect/netstorage/netstorage.go

@@ -20,6 +20,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/fasttime"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/flagutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/querytracer"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage/metricnamestats"
@@ -30,11 +31,12 @@ var (
 	maxSamplesPerSeries = flag.Int("search.maxSamplesPerSeries", 30e6, "The maximum number of raw samples a single query can scan per each time series. This option allows limiting memory usage")
 	maxSamplesPerQuery  = flag.Int("search.maxSamplesPerQuery", 1e9, "The maximum number of raw samples a single query can process across all time series. "+
 		"This protects from heavy queries, which select unexpectedly high number of raw samples. See also -search.maxSamplesPerSeries")
-	maxWorkersPerQuery = flag.Int("search.maxWorkersPerQuery", defaultMaxWorkersPerQuery, "The maximum number of CPU cores a single query can use. "+
-		"The default value should work good for most cases. "+
-		"The flag can be set to lower values for improving performance of big number of concurrently executed queries. "+
-		"The flag can be set to bigger values for improving performance of heavy queries, which scan big number of time series (>10K) and/or big number of samples (>100M). "+
-		"There is no sense in setting this flag to values bigger than the number of CPU cores available on the system")
+	maxWorkersPerQuery = flagutil.NewIntWithDynamicDefault("search.maxWorkersPerQuery", defaultMaxWorkersPerQuery, "netstorage.defaultMaxWorkersPerQuery()",
+		"The maximum number of CPU cores a single query can use. "+
+			"The default value should work good for most cases. "+
+			"The flag can be set to lower values for improving performance of big number of concurrently executed queries. "+
+			"The flag can be set to bigger values for improving performance of heavy queries, which scan big number of time series (>10K) and/or big number of samples (>100M). "+
+			"There is no sense in setting this flag to values bigger than the number of CPU cores available on the system")
 )
 
 // Result is a single timeseries result.

deployment/docker/rules/alerts-health.yml

@@ -16,6 +16,19 @@ groups:
             Job {{ $labels.job }} (instance {{ $labels.instance }}) has restarted more than twice in the last 15 minutes.
             It might be crashlooping.
 
+      - alert: UncleanShutdown
+        expr: vm_app_prev_shutdown_unclean == 1 and time() - vm_app_start_timestamp < 600
+        labels:
+          severity: warning
+        annotations:
+          summary: "{{ $labels.job }} on instance {{ $labels.instance }} started after an unclean shutdown"
+          description: |
+            The previous process run didn't shut down cleanly. Check the logs for OOM, SIGKILL,
+            a host failure, or another unexpected termination. In Kubernetes, a pod may be forcefully
+            killed with SIGKILL if the shutdown takes longer than terminationGracePeriodSeconds.
+            This alert stops firing 10 minutes after startup.
+            See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/8443 for more details.
+
       - alert: ServiceDown
         expr: up{job=~".*(victoriametrics|vmselect|vminsert|vmstorage|vmagent|vmalert|vmsingle|vmalertmanager|vmauth).*"} == 0
         for: 2m

docs/Makefile

@@ -90,12 +90,9 @@ endif
 	sed -i 's/\t/ /g' docs/victoriametrics/victoria_metrics_common_flags.md
 	sed -i 's/\t/ /g' docs/victoriametrics/victoria_metrics_enterprise_flags.md
 
-	# adjust flags with dynamic default values
-	# remove after https://github.com/VictoriaMetrics/VictoriaMetrics/issues/9680 implemented
-	sed -i '/The maximum number of concurrent insert requests/ s/(default [0-9]\+)/(default 2*cgroup.AvailableCPUs())/' docs/victoriametrics/victoria_metrics_common_flags.md
-	sed -i '/The maximum number of concurrent search requests\./ s/(default [0-9]\+)/(default vmselect.getDefaultMaxConcurrentRequests())/' docs/victoriametrics/victoria_metrics_common_flags.md
-	sed -i '/The maximum number of CPU cores a single query can use\./ s/(default [0-9]\+)/(default netstorage.defaultMaxWorkersPerQuery())/' docs/victoriametrics/victoria_metrics_common_flags.md
-	sed -i '/The maximum number of concurrent goroutines to work with files;/ s/(default [0-9]\+)/(default fsutil.getDefaultConcurrency())/' docs/victoriametrics/victoria_metrics_common_flags.md
+	# hide the machine-specific value of dynamic defaults, keeping the formula.
+	# the flagutil.New*WithDynamicDefault constructors print them as "(default <value> = <formula>)".
+	sed -i 's/(default [0-9]\+ = \(.*\))$$/(default \1)/' docs/victoriametrics/victoria_metrics_common_flags.md
 
 docs-update-vmauth-flags:
 ifndef TAG
@@ -119,9 +116,9 @@ endif
 	sed -i 's/\t/ /g' docs/victoriametrics/vmauth_common_flags.md
 	sed -i 's/\t/ /g' docs/victoriametrics/vmauth_enterprise_flags.md
 
-	# adjust flags with dynamic default values
-	# remove after https://github.com/VictoriaMetrics/VictoriaMetrics/issues/9680 implemented
-	sed -i '/The maximum number of concurrent goroutines to work with files;/ s/(default [0-9]\+)/(default fsutil.getDefaultConcurrency())/' docs/victoriametrics/vmauth_common_flags.md
+	# hide the machine-specific value of dynamic defaults, keeping the formula.
+	# the flagutil.New*WithDynamicDefault constructors print them as "(default <value> = <formula>)".
+	sed -i 's/(default [0-9]\+ = \(.*\))$$/(default \1)/' docs/victoriametrics/vmauth_common_flags.md
 
 docs-update-vmagent-flags:
 ifndef TAG
@@ -145,11 +142,9 @@ endif
 	sed -i 's/\t/ /g' docs/victoriametrics/vmagent_common_flags.md
 	sed -i 's/\t/ /g' docs/victoriametrics/vmagent_enterprise_flags.md
 
-	# adjust flags with dynamic default values
-	# remove after https://github.com/VictoriaMetrics/VictoriaMetrics/issues/9680 implemented
-	sed -i '/The maximum number of concurrent insert requests/ s/(default [0-9]\+)/(default 2*cgroup.AvailableCPUs())/' docs/victoriametrics/vmagent_common_flags.md
-	sed -i '/The number of concurrent queues to each -remoteWrite.url./ s/(default [0-9]\+)/(default 2*cgroup.AvailableCPUs())/' docs/victoriametrics/vmagent_common_flags.md
-	sed -i '/The maximum number of concurrent goroutines to work with files;/ s/(default [0-9]\+)/(default fsutil.getDefaultConcurrency())/' docs/victoriametrics/vmagent_common_flags.md
+	# hide the machine-specific value of dynamic defaults, keeping the formula.
+	# the flagutil.New*WithDynamicDefault constructors print them as "(default <value> = <formula>)".
+	sed -i 's/(default [0-9]\+ = \(.*\))$$/(default \1)/' docs/victoriametrics/vmagent_common_flags.md
 
 docs-update-vmalert-flags:
 ifndef TAG
@@ -173,10 +168,9 @@ endif
 	sed -i 's/\t/ /g' docs/victoriametrics/vmalert_common_flags.md
 	sed -i 's/\t/ /g' docs/victoriametrics/vmalert_enterprise_flags.md
 
-	# adjust flags with dynamic default values
-	# remove after https://github.com/VictoriaMetrics/VictoriaMetrics/issues/9680 implemented
-	sed -i '/Defines number of writers for concurrent writing into remote write endpoint./ s/(default [0-9]\+)/(default 2*cgroup.AvailableCPUs())/' docs/victoriametrics/vmalert_common_flags.md
-	sed -i '/The maximum number of concurrent goroutines to work with files;/ s/(default [0-9]\+)/(default fsutil.getDefaultConcurrency())/' docs/victoriametrics/vmalert_common_flags.md
+	# hide the machine-specific value of dynamic defaults, keeping the formula.
+	# the flagutil.New*WithDynamicDefault constructors print them as "(default <value> = <formula>)".
+	sed -i 's/(default [0-9]\+ = \(.*\))$$/(default \1)/' docs/victoriametrics/vmalert_common_flags.md
 
 docs-update-vmselect-flags:
 ifndef TAG

docs/victoriametrics/changelog/CHANGELOG.md

@@ -26,7 +26,10 @@ See also [LTS releases](https://docs.victoriametrics.com/victoriametrics/lts-rel
 
 ## tip
 
+* FEATURE: [vmagent](https://docs.victoriametrics.com/victoriametrics/vmagent/), [vmsingle](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/), `vmstorage` and `vmselect` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/): expose the `vm_app_prev_shutdown_unclean` gauge. It is set to `1` when the previous process run didn't shut down cleanly. Added the `UncleanShutdown` [alerting rule](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/deployment/docker/rules/alerts-health.yml), which fires for 10 minutes after an unclean shutdown is detected. See [#8443](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/8443).
 * FEATURE: [vmui](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#vmui): show the selected time zone UTC offset next to the date/time controls and allow opening time zone settings from it. See [#11332](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/11332).
+* FEATURE: [vmsingle](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/), [vmagent](https://docs.victoriametrics.com/victoriametrics/vmagent/), [vmalert](https://docs.victoriametrics.com/victoriametrics/vmalert/), and `vmselect` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/): show how the default value is calculated for command-line flags which derive it from the number of available CPU cores. For example, `-maxConcurrentInserts` now prints `(default 16 = 2*cgroup.AvailableCPUs())` in `-help` output instead of `(default 16)`. Updated flags: `-search.maxConcurrentRequests`, `-search.maxWorkersPerQuery`, `-fs.maxConcurrency`, `-remoteWrite.concurrency`, `-remoteWrite.queues`. See [#9680](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/9680). Thanks to @Vandit1604 for contribution.
+* FEATURE: [vmsingle](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/) and `vmselect` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/): accept Unix timestamp values with negative scientific notation exponents in [Prometheus querying API](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#prometheus-querying-api-usage) time parameters such as `start` and `end` in `/api/v1/query_range`. Previously, values such as `1000e-1` were rejected. See [#11427](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/11427).
 
 * BUGFIX: [vmagent](https://docs.victoriametrics.com/victoriametrics/vmagent/) and `vminsert` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/): fix infinite loop in the OpenTelemetry Firehose ingestion endpoint (`/opentelemetry/api/v1/push`) when receiving a malformed record with an incomplete varint in the `data` field. Previously this caused the goroutine to spin forever, permanently consuming CPU until the process was restarted.
 * BUGFIX: [vmalert-tool](https://docs.victoriametrics.com/victoriametrics/vmalert-tool/): reuse connections to `-remoteWrite.url` when writing the results of recording rules and alerts. Previously every series was sent over a new connection, which left a lot of sockets in `TIME_WAIT` state and could exhaust the ephemeral port range. The number of idle connections can be tuned via the new `-remoteWrite.maxIdleConnections` command-line flag. Thanks @evkuzin for contribution.

docs/victoriametrics/integrations/grafana/_index.md

@@ -50,7 +50,7 @@ If you don't see an option to create a data source - try contacting system admin
 Create [Prometheus datasource](https://grafana.com/docs/grafana/latest/datasources/prometheus/configure/)
 in Grafana. Follow the same connection instructions as for [VictoriaMetrics datasource](#VictoriaMetrics-datasource).
 
-In the "Type and version" section set the type to "Prometheus" and the version to at least "2.24.x".
+In the "Performance" section set the Prometheus type to "Prometheus" and the Prometheus version to at least "2.24.x".
 This allows Grafana to use a more efficient API to get label values:
 
 ![Datasource](datasource-prometheus.webp)

docs/victoriametrics/vmalert.md

@@ -1127,13 +1127,18 @@ Or for all rules within the [group](#groups) {{% available_from "v1.117.0" %}}.
 Just set `debug: true` in configuration and vmalert will start printing additional log messages:
 
 ```sh
-2022-09-15T13:35:41.155Z  DEBUG alerting rule "TestGroup":"Conns" (2601299393013563564) at 2022-09-15T15:35:41+02:00: query returned 0 series (elapsed: 5.896041ms, isPartial: false)
-2022-09-15T13:35:56.149Z  DEBUG datasource request: executing POST request with params "denyPartialResponse=true&query=sum%28vm_tcplistener_conns%7Binstance%3D%22localhost%3A8429%22%7D%29+by%28instance%29+%3E+0&step=15s&time=1663248945"
-2022-09-15T13:35:56.178Z  DEBUG alerting rule "TestGroup":"Conns" (2601299393013563564) at 2022-09-15T15:35:56+02:00: query returned 1 series (elapsed: 28.368208ms, isPartial: false)
-2022-09-15T13:35:56.178Z  DEBUG datasource request: executing POST request with params "denyPartialResponse=true&query=sum%28vm_tcplistener_conns%7Binstance%3D%22localhost%3A8429%22%7D%29&step=15s&time=1663248945"
-2022-09-15T13:35:56.179Z  DEBUG alerting rule "TestGroup":"Conns" (2601299393013563564) at 2022-09-15T15:35:56+02:00: alert 10705778000901301787 {alertgroup="TestGroup",alertname="Conns",cluster="east-1",instance="localhost:8429",replica="a"} created in state PENDING
+2026-08-20T08:21:29.464Z        info    VictoriaMetrics/app/vmalert/datasource/client.go:262    DEBUG datasource request: executing POST request with params "http://victoriametrics:8428/api/v1/query?query=up%7Bjob%3D~%22.%2A%28victoriametrics%7Cvmselect%7Cvminsert%7Cvmstorage%7Cvmagent%7Cvmalert%7Cvmsingle%7Cvmalertmanager%7Cvmauth%29.%2A%22%7D&step=300s&time=2026-08-20T08%3A20%3A00Z"
+2026-08-20T08:21:29.465Z        info    VictoriaMetrics/app/vmalert/rule/alerting.go:273        DEBUG alerting rule "/etc/alerts/alerts-health.yml", "vm-health":"ServiceDown" (1340947595484135783) at 2026-08-20T08:20:00Z: query returned 0 series (series_fetched: 0, elapsed: 1.075166ms, isPartial: false)
 ...
-2022-09-15T13:36:56.153Z  DEBUG alerting rule "TestGroup":"Conns" (2601299393013563564) at 2022-09-15T15:36:56+02:00: alert 10705778000901301787 {alertgroup="TestGroup",alertname="Conns",cluster="east-1",instance="localhost:8429",replica="a"} PENDING => FIRING: 1m0s since becoming active at 2022-09-15 15:35:56.126006 +0200 CEST m=+39.384575417
+2026-08-20T08:22:29.466Z        info    VictoriaMetrics/app/vmalert/datasource/client.go:262    DEBUG datasource request: executing POST request with params "http://victoriametrics:8428/api/v1/query?query=up%7Bjob%3D~%22.%2A%28victoriametrics%7Cvmselect%7Cvminsert%7Cvmstorage%7Cvmagent%7Cvmalert%7Cvmsingle%7Cvmalertmanager%7Cvmauth%29.%2A%22%7D&step=300s&time=2026-08-20T08%3A21%3A00Z"
+2026-08-20T08:22:29.468Z        info    VictoriaMetrics/app/vmalert/rule/alerting.go:273        DEBUG alerting rule "/etc/alerts/alerts-health.yml", "vm-health":"ServiceDown" (1340947595484135783) at 2026-08-20T08:21:00Z: query returned 2 series (series_fetched: 2, elapsed: 2.055916ms, isPartial: false)
+2026-08-20T08:22:29.469Z        info    VictoriaMetrics/app/vmalert/rule/alerting.go:273        DEBUG alerting rule "/etc/alerts/alerts-health.yml", "vm-health":"ServiceDown" (1340947595484135783) at 2026-08-20T08:21:00Z: alert 4671711516378822929 {alertgroup="vm-health",alertname="ServiceDown",instance="victoriametrics:8428",job="victoriametrics",severity="critical"} created in state PENDING
+2026-08-20T08:22:29.469Z        info    VictoriaMetrics/app/vmalert/rule/alerting.go:273        DEBUG alerting rule "/etc/alerts/alerts-health.yml", "vm-health":"ServiceDown" (1340947595484135783) at 2026-08-20T08:21:00Z: alert 6230585559362831632 {alertgroup="vm-health",alertname="ServiceDown",instance="vmagent:8429",job="vmagent",severity="critical"} created in state PENDING
+...
+2026-08-20T08:23:29.463Z        info    VictoriaMetrics/app/vmalert/datasource/client.go:262    DEBUG datasource request: executing POST request with params "http://victoriametrics:8428/api/v1/query?query=up%7Bjob%3D~%22.%2A%28victoriametrics%7Cvmselect%7Cvminsert%7Cvmstorage%7Cvmagent%7Cvmalert%7Cvmsingle%7Cvmalertmanager%7Cvmauth%29.%2A%22%7D&step=300s&time=2026-08-20T08%3A22%3A00Z"
+2026-08-20T08:23:29.465Z        info    VictoriaMetrics/app/vmalert/rule/alerting.go:273        DEBUG alerting rule "/etc/alerts/alerts-health.yml", "vm-health":"ServiceDown" (1340947595484135783) at 2026-08-20T08:22:00Z: query returned 2 series (series_fetched: 2, elapsed: 1.391416ms, isPartial: false)
+2026-08-20T08:23:29.466Z        info    VictoriaMetrics/app/vmalert/rule/alerting.go:273        DEBUG alerting rule "/etc/alerts/alerts-health.yml", "vm-health":"ServiceDown" (1340947595484135783) at 2026-08-20T08:22:00Z: alert 4671711516378822929 {alertgroup="vm-health",alertname="ServiceDown",instance="victoriametrics:8428",job="victoriametrics",severity="critical"} PENDING => FIRING: 1m0s since becoming active at 2026-08-20 08:21:00 +0000 UTC
+2026-08-20T08:23:29.466Z        info    VictoriaMetrics/app/vmalert/rule/alerting.go:273        DEBUG alerting rule "/etc/alerts/alerts-health.yml", "vm-health":"ServiceDown" (1340947595484135783) at 2026-08-20T08:22:00Z: alert 6230585559362831632 {alertgroup="vm-health",alertname="ServiceDown",instance="vmagent:8429",job="vmagent",severity="critical"} PENDING => FIRING: 1m0s since becoming active at 2026-08-20 08:21:00 +0000 UTC
 ```
 
 Sensitive info is stripped from the `curl` examples - see [security](#security) section for more details.

lib/appmetrics/appmetrics.go

@@ -65,6 +65,9 @@ func writePrometheusMetrics(w io.Writer) {
 	// Export start time and uptime in seconds
 	metrics.WriteGaugeUint64(w, "vm_app_start_timestamp", uint64(startTime.Unix()))
 	metrics.WriteGaugeUint64(w, "vm_app_uptime_seconds", uint64(time.Since(startTime).Seconds()))
+	if uncleanShutdownEnabled.Load() {
+		metrics.WriteGaugeUint64(w, "vm_app_prev_shutdown_unclean", uncleanShutdown)
+	}
 
 	// Export flags as metrics.
 	isSetMap := make(map[string]bool)

lib/appmetrics/osmetrics.go

@@ -13,13 +13,13 @@ type osInfo struct {
 	release string
 }
 
-var os osInfo
+var hostOS osInfo
 var initOSOnce sync.Once
 
 func writeOSMetrics(w io.Writer) {
 	initOSOnce.Do(initOS)
 
-	if os.name != "" {
-		metrics.WriteGaugeUint64(w, fmt.Sprintf(`vm_os_info{os=%q, release=%q}`, os.name, os.release), 1)
+	if hostOS.name != "" {
+		metrics.WriteGaugeUint64(w, fmt.Sprintf(`vm_os_info{os=%q, release=%q}`, hostOS.name, hostOS.release), 1)
 	}
 }

lib/appmetrics/osmetrics_darwin.go

@@ -8,7 +8,7 @@ import (
 )
 
 func initOS() {
-	os = osInfo{name: "darwin"}
+	hostOS = osInfo{name: "darwin"}
 
 	out, err := exec.Command("sysctl", "-n", "kern.osrelease").Output()
 	if err != nil {
@@ -16,5 +16,5 @@ func initOS() {
 		return
 	}
 
-	os.release = strings.TrimSpace(string(out))
+	hostOS.release = strings.TrimSpace(string(out))
 }

lib/appmetrics/osmetrics_linux.go

@@ -7,7 +7,7 @@ import (
 )
 
 func initOS() {
-	os = osInfo{name: "linux"}
+	hostOS = osInfo{name: "linux"}
 
 	var uname syscall.Utsname
 	if err := syscall.Uname(&uname); err != nil {
@@ -22,5 +22,5 @@ func initOS() {
 		}
 		ur = append(ur, byte(v))
 	}
-	os.release = string(ur)
+	hostOS.release = string(ur)
 }

lib/appmetrics/osmetrics_windows.go

@@ -8,12 +8,12 @@ import (
 )
 
 func initOS() {
-	os = osInfo{name: "windows"}
+	hostOS = osInfo{name: "windows"}
 
 	ver := windows.RtlGetVersion()
 	if ver == nil {
 		logger.Warnf("vm_os_info metric will miss release info since windows.RtlGetVersion returned nil version")
 		return
 	}
-	os.release = fmt.Sprintf("%d.%d.%d", ver.MajorVersion, ver.MinorVersion, ver.BuildNumber)
+	hostOS.release = fmt.Sprintf("%d.%d.%d", ver.MajorVersion, ver.MinorVersion, ver.BuildNumber)
 }

lib/appmetrics/unclean_shutdown.go

@@ -0,0 +1,53 @@
+package appmetrics
+
+import (
+	"os"
+	"path/filepath"
+	"sync/atomic"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/fs"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
+)
+
+// UncleanShutdownMarkerFilename is the marker file used to detect a previous unclean shutdown.
+const UncleanShutdownMarkerFilename = ".vm_app_running"
+
+var (
+	uncleanShutdownEnabled atomic.Bool
+	uncleanShutdown        uint64
+)
+
+// MustCreateUncleanShutdownMarker creates an UncleanShutdownMarkerFilename marker file in the given dirPath.
+// Must be called once on program startup and paired with a single MustRemoveUncleanShutdownMarker call on exit.
+//
+// If the marker file already exists on startup, it indicates a previous unclean shutdown and uncleanShutdown is set to 1.
+func MustCreateUncleanShutdownMarker(dirPath string) {
+	if !uncleanShutdownEnabled.CompareAndSwap(false, true) {
+		logger.Fatalf("BUG: unclean shutdown marker was already initialized. It could only be called once")
+	}
+	marker := filepath.Join(dirPath, UncleanShutdownMarkerFilename)
+	f, err := os.OpenFile(marker, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0600)
+	if err == nil {
+		fs.MustClose(f)
+		return
+	}
+	if os.IsExist(err) {
+		uncleanShutdown = 1
+		logger.Warnf("Previous shutdown was unclean since file %q exists. Please check logs and investigate the reason of unclean shutdown", marker)
+		return
+	}
+	logger.Panicf("FATAL: cannot create unclean shutdown marker %q: %s", marker, err)
+}
+
+// MustRemoveUncleanShutdownMarker removes the UncleanShutdownMarkerFilename marker file created by MustCreateUncleanShutdownMarker.
+// Must be called once, as late as possible before program exit.
+func MustRemoveUncleanShutdownMarker(dirPath string) {
+	if !uncleanShutdownEnabled.Load() {
+		logger.Fatalf("BUG: unclean shutdown marker was not initialized with MustCreateUncleanShutdownMarker call")
+	}
+	marker := filepath.Join(dirPath, UncleanShutdownMarkerFilename)
+	if err := os.Remove(marker); err != nil {
+		logger.Fatalf("FATAL: cannot remove unclean shutdown marker %q: %s", marker, err)
+	}
+	fs.MustSyncPath(dirPath)
+}

lib/appmetrics/unclean_shutdown_test.go

@@ -0,0 +1,60 @@
+package appmetrics
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+func TestUncleanShutdownLifecycle(t *testing.T) {
+
+	t.Cleanup(func() {
+		uncleanShutdownEnabled.Store(false)
+	})
+	dirPath := t.TempDir()
+	markerPath := filepath.Join(dirPath, UncleanShutdownMarkerFilename)
+
+	// unclean logic is disabled. the unclean shutdown metric should not be exposed
+	var bb bytes.Buffer
+	writePrometheusMetrics(&bb)
+	if strings.Contains(bb.String(), "vm_app_prev_shutdown_unclean") {
+		t.Fatalf("unexpected unclean shutdown metric before starting the marker")
+	}
+
+	// clean start, the metric must report 0
+	MustCreateUncleanShutdownMarker(dirPath)
+	mustContainUncleanShutdownMetric(t, 0)
+	if _, err := os.Stat(markerPath); err != nil {
+		t.Fatalf("cannot stat the running marker after the first start: %s", err)
+	}
+	MustRemoveUncleanShutdownMarker(dirPath)
+	if _, err := os.Stat(markerPath); !os.IsNotExist(err) {
+		t.Fatalf("unexpected running marker after a clean shutdown; got error %v; want os.ErrNotExist", err)
+	}
+	uncleanShutdownEnabled.Store(false)
+
+	// simulate prev unclean shutdown, the metric must report 1
+	if err := os.WriteFile(markerPath, nil, 0600); err != nil {
+		t.Fatalf("cannot create test marker: %s", err)
+	}
+	MustCreateUncleanShutdownMarker(dirPath)
+	mustContainUncleanShutdownMetric(t, 1)
+	MustRemoveUncleanShutdownMarker(dirPath)
+	if _, err := os.Stat(markerPath); !os.IsNotExist(err) {
+		t.Fatalf("unexpected running marker after a clean shutdown; got error %v; want os.ErrNotExist", err)
+	}
+}
+
+func mustContainUncleanShutdownMetric(t *testing.T, value uint64) {
+	t.Helper()
+
+	var bb bytes.Buffer
+	writePrometheusMetrics(&bb)
+	want := "vm_app_prev_shutdown_unclean " + strconv.FormatUint(value, 10) + "\n"
+	if !strings.Contains(bb.String(), want) {
+		t.Fatalf("missing %q in the exported app metrics", want)
+	}
+}

lib/backup/fscommon/fscommon.go

@@ -6,6 +6,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/appmetrics"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/backup/backupnames"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
 )
@@ -107,7 +108,7 @@ func appendFilesInternal(dst []string, d *os.File) ([]string, error) {
 }
 
 func isSpecialFile(name string) bool {
-	return name == "flock.lock" || name == backupnames.RestoreInProgressFilename || name == backupnames.RestoreMarkFileName || strings.HasSuffix(name, ".tmp")
+	return name == "flock.lock" || name == appmetrics.UncleanShutdownMarkerFilename || name == backupnames.RestoreInProgressFilename || name == backupnames.RestoreMarkFileName || strings.HasSuffix(name, ".tmp")
 }
 
 // RemoveEmptyDirs recursively removes empty directories under the given dir.

lib/flagutil/array.go

@@ -39,8 +39,29 @@ func NewArrayBool(name, description string) *ArrayBool {
 }
 
 // NewArrayInt returns new ArrayInt with the given name, defaultValue and description.
+//
+// -help shows defaultValue as a plain number. Use NewArrayIntWithDynamicDefault when
+// defaultValue is calculated at runtime.
 func NewArrayInt(name string, defaultValue int, description string) *ArrayInt {
-	description += fmt.Sprintf(" (default %d)", defaultValue)
+	return newArrayInt(name, defaultValue, strconv.Itoa(defaultValue), description)
+}
+
+// NewArrayIntWithDynamicDefault returns new ArrayInt with the given name, defaultValue and description.
+//
+// Use it instead of NewArrayInt when defaultValue is calculated at runtime.
+// See NewIntWithDynamicDefault for why such a value needs a hint.
+func NewArrayIntWithDynamicDefault(name string, defaultValue int, defaultValueHint, description string) *ArrayInt {
+	if defaultValueHint == "" {
+		panic(fmt.Sprintf("BUG: missing defaultValueHint for -%s", name))
+	}
+	return newArrayInt(name, defaultValue, fmt.Sprintf("%d = %s", defaultValue, defaultValueHint), description)
+}
+
+// newArrayInt registers an int array flag, which shows defaultValueText as its default in -help.
+//
+// Array flags keep the default in the description, since flag.Var hides an empty DefValue.
+func newArrayInt(name string, defaultValue int, defaultValueText, description string) *ArrayInt {
+	description += fmt.Sprintf(" (default %s)", defaultValueText)
 	description += "\nSupports `array` of values separated by comma or specified via multiple flags."
 	description += "\nEmpty values are set to default value."
 	a := &ArrayInt{

lib/flagutil/flag.go

@@ -7,6 +7,25 @@ import (
 	"strings"
 )
 
+// NewIntWithDynamicDefault returns a new int flag with the given name, defaultValue and description.
+//
+// Use it instead of flag.Int when defaultValue is calculated at runtime, for example
+// from the number of CPU cores. Such a value differs per machine, so -help shows both
+// the value and defaultValueHint, for example "16 = 2 * availableCPUs".
+//
+// Only -help output changes. The flag value stays defaultValue.
+func NewIntWithDynamicDefault(name string, defaultValue int, defaultValueHint, description string) *int {
+	if defaultValueHint == "" {
+		panic(fmt.Sprintf("BUG: missing defaultValueHint for -%s", name))
+	}
+	p := flag.Int(name, defaultValue, description)
+
+	// DefValue is only the text shown by -help: "default value (as text); for usage message".
+	flag.Lookup(name).DefValue = fmt.Sprintf("%d = %s", defaultValue, defaultValueHint)
+
+	return p
+}
+
 // WriteFlags writes all the explicitly set flags to w.
 func WriteFlags(w io.Writer) {
 	flag.Visit(func(f *flag.Flag) {

lib/flagutil/flag_test.go

@@ -0,0 +1,51 @@
+package flagutil
+
+import (
+	"flag"
+	"strings"
+	"testing"
+)
+
+// The flags are registered at package level, since flag registration panics when it repeats.
+var (
+	fooFlagIntDynamicDefault      = NewIntWithDynamicDefault("fooFlagIntDynamicDefault", 42, "2 * availableCPUs", "test")
+	fooFlagArrayIntDynamicDefault = NewArrayIntWithDynamicDefault("fooFlagArrayIntDynamicDefault", 42, "2 * availableCPUs", "test")
+	fooFlagArrayIntPlainDefault   = NewArrayInt("fooFlagArrayIntPlainDefault", 42, "test")
+)
+
+func TestNewIntWithDynamicDefaultSuccess(t *testing.T) {
+	// -help must show the value together with the hint.
+	f := flag.Lookup("fooFlagIntDynamicDefault")
+	if f.DefValue != "42 = 2 * availableCPUs" {
+		t.Fatalf("unexpected DefValue; got %q; want %q", f.DefValue, "42 = 2 * availableCPUs")
+	}
+
+	// the flag value must stay the calculated one.
+	if *fooFlagIntDynamicDefault != 42 {
+		t.Fatalf("unexpected flag value; got %d; want %d", *fooFlagIntDynamicDefault, 42)
+	}
+}
+
+func TestNewArrayIntWithDynamicDefaultSuccess(t *testing.T) {
+	// array flags keep the default in the description, so the hint must go there.
+	f := flag.Lookup("fooFlagArrayIntDynamicDefault")
+	if !strings.Contains(f.Usage, "(default 42 = 2 * availableCPUs)") {
+		t.Fatalf("missing the hint in the flag description; got %q", f.Usage)
+	}
+
+	// the default value must stay the calculated one.
+	if n := fooFlagArrayIntDynamicDefault.GetOptionalArg(0); n != 42 {
+		t.Fatalf("unexpected default value; got %d; want %d", n, 42)
+	}
+}
+
+func TestNewArrayIntKeepsPlainDefault(t *testing.T) {
+	// NewArrayInt must keep showing a plain number, since it shares the body with the dynamic one.
+	f := flag.Lookup("fooFlagArrayIntPlainDefault")
+	if !strings.Contains(f.Usage, "(default 42)") {
+		t.Fatalf("unexpected flag description; got %q", f.Usage)
+	}
+	if n := fooFlagArrayIntPlainDefault.GetOptionalArg(0); n != 42 {
+		t.Fatalf("unexpected default value; got %d; want %d", n, 42)
+	}
+}

lib/fs/fsutil/concurrency.go

@@ -1,14 +1,15 @@
 package fsutil
 
 import (
-	"flag"
 	"sync"
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/flagutil"
 )
 
-var maxConcurrency = flag.Int("fs.maxConcurrency", getDefaultConcurrency(), "The maximum number of concurrent goroutines to work with files; smaller values may help reducing Go scheduling latency "+
-	"on systems with small number of CPU cores; higher values may help reducing data ingestion latency on systems with high-latency storage such as NFS or Ceph")
+var maxConcurrency = flagutil.NewIntWithDynamicDefault("fs.maxConcurrency", getDefaultConcurrency(), "fsutil.getDefaultConcurrency()",
+	"The maximum number of concurrent goroutines to work with files; smaller values may help reducing Go scheduling latency "+
+		"on systems with small number of CPU cores; higher values may help reducing data ingestion latency on systems with high-latency storage such as NFS or Ceph")
 
 func getDefaultConcurrency() int {
 	n := min(16*cgroup.AvailableCPUs(), 256)

lib/timeutil/time.go

@@ -79,7 +79,7 @@ func ParseTimeAt(s string, currentTimestamp int64) (int64, error) {
 		// Parse YYYY
 		return parseTimeAt("2006", s, tzOffset, sOrig)
 	}
-	if !strings.Contains(sOrig, "-") {
+	if !strings.Contains(sOrig, "-") || getExpIndex(sOrig) >= 0 {
 		nsec, ok := TryParseUnixTimestamp(sOrig)
 		if !ok {
 			return 0, fmt.Errorf("cannot parse numeric timestamp %q", sOrig)
@@ -186,80 +186,84 @@ func getExpIndex(s string) int {
 }
 
 func tryParseScientificUnixTimestamp(s string, decimalExp int64) (int64, bool) {
-	if decimalExp < 0 {
-		// Negative exponents on a fractional mantissa are intentionally not
-		// supported. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/11268
+	intStr, fracStr, ok := expandScientificUnixTimestamp(s, decimalExp)
+	if !ok {
 		return 0, false
 	}
-	dotIdx := strings.IndexByte(s, '.')
-	if dotIdx < 0 {
-		n, ok := tryParseInt64(s)
-		if !ok {
-			return 0, false
-		}
-		n, ok = multiplyByDecimalExp(n, decimalExp)
+	if fracStr == "" {
+		n, ok := tryParseInt64(intStr)
 		if !ok {
 			return 0, false
 		}
 		return getUnixTimestampNanoseconds(n), true
 	}
-
-	intStr := s[:dotIdx]
-	fracStr := s[dotIdx+1:]
-	if decimalExp >= int64(len(fracStr)) {
-		// The exponent shifts the decimal point past every fractional digit.
-		n, ok := tryParseDecimalMantissaAsInt(intStr, fracStr)
-		if !ok {
-			return 0, false
-		}
-		decimalExp -= int64(len(fracStr))
-		n, ok = multiplyByDecimalExp(n, decimalExp)
-		if !ok {
-			return 0, false
-		}
-		return getUnixTimestampNanoseconds(n), true
-	}
-
-	// The exponent leaves fractional digits, e.g. 1.784144612388E9 == 1784144612.388
-	if decimalExp >= int64(len(decimalMultipliers)) {
-		return 0, false
-	}
-	decimalExpInt := int(decimalExp)
-	intStr = s[:dotIdx] + fracStr[:decimalExpInt]
-	fracStr = fracStr[decimalExpInt:]
 	return tryParseFractionalUnixTimestamp(intStr, fracStr)
 }
 
-func tryParseDecimalMantissaAsInt(intStr, fracStr string) (int64, bool) {
-	n, ok := tryParseInt64(intStr)
-	if !ok {
-		return 0, false
+func expandScientificUnixTimestamp(s string, decimalExp int64) (string, string, bool) {
+	dotIdx := strings.IndexByte(s, '.')
+	intStr := s
+	fracStr := ""
+	if dotIdx >= 0 {
+		intStr = s[:dotIdx]
+		fracStr = s[dotIdx+1:]
+	}
+	if _, ok := tryParseInt64(intStr); !ok {
+		return "", "", false
+	}
+	if !isDecimalString(fracStr) {
+		return "", "", false
 	}
 
-	decimalExp := int64(len(fracStr))
-	num, ok := multiplyByDecimalExp(n, decimalExp)
-	if !ok {
-		return 0, false
-	}
-
-	frac, ok := tryParseInt64(fracStr)
-	if !ok {
-		return 0, false
-	}
-
-	if num >= 0 {
-		if num > math.MaxInt64-frac {
-			return 0, false
+	isNegativeExp := decimalExp < 0
+	if isNegativeExp {
+		if decimalExp <= -int64(len(decimalMultipliers)) {
+			return "", "", false
 		}
-		num += frac
+		decimalExp = -decimalExp
+	}
+	if decimalExp > int64(math.MaxInt) || decimalExp < int64(math.MinInt) {
+		return "", "", false
+	}
+
+	intStr = strings.TrimPrefix(intStr, "+")
+	isNegative := strings.HasPrefix(intStr, "-")
+	if isNegative {
+		intStr = intStr[1:]
+	}
+
+	var shiftedIntStr, shiftedFracStr string
+	if isNegativeExp {
+		// e.g.
+		// 1. the integer and fractional part of 1.23e-5 should be 0 and 0000123 respectively.
+		// 2. the integer and fractional part of 123.4e-1 should be 12 and 34 respectively.
+		if decimalExp >= int64(len(intStr)) {
+			zerosToAdd := decimalExp - int64(len(intStr))
+			shiftedIntStr = "0"
+			shiftedFracStr = strings.Repeat("0", int(zerosToAdd)) + intStr + fracStr
+		} else {
+			decimalExpInt := int(decimalExp)
+			shiftedIntStr = intStr[:len(intStr)-decimalExpInt]
+			shiftedFracStr = intStr[len(intStr)-decimalExpInt:] + fracStr
+		}
+	} else if decimalExp >= int64(len(fracStr)) {
+		zerosToAdd := decimalExp - int64(len(fracStr))
+		if zerosToAdd >= int64(len(decimalMultipliers)) {
+			return "", "", false
+		}
+		// e.g. the integer part and fractional part of 1.23e5 should be 123000 and 0 respectively.
+		shiftedIntStr = intStr + fracStr + strings.Repeat("0", int(zerosToAdd))
+		shiftedFracStr = ""
 	} else {
-		if num < math.MinInt64+frac {
-			return 0, false
-		}
-		num -= frac
+		decimalExpInt := int(decimalExp)
+		shiftedIntStr = intStr + fracStr[:decimalExpInt]
+		shiftedFracStr = fracStr[decimalExpInt:]
 	}
 
-	return num, true
+	if isNegative {
+		shiftedIntStr = "-" + shiftedIntStr
+	}
+	return shiftedIntStr, shiftedFracStr, true
 }
 
 func tryParseFractionalUnixTimestamp(intStr, fracStr string) (int64, bool) {
@@ -270,15 +274,11 @@ func tryParseFractionalUnixTimestamp(intStr, fracStr string) (int64, bool) {
 	isNegative := n < 0 || n == 0 && strings.HasPrefix(intStr, "-")
 
 	multiplier, maxFracDigits := getUnixTimestampMultiplier(n)
+	if !isDecimalString(fracStr) {
+		return 0, false
+	}
 	// Truncate the fractional digits to valid length according to the unit precision.
 	if len(fracStr) > maxFracDigits {
-		// 1.123456789XXX is invalid.
-		tail := fracStr[maxFracDigits:]
-		for i := 0; i < len(tail); i++ {
-			if tail[i] < '0' || tail[i] > '9' {
-				return 0, false
-			}
-		}
 		fracStr = fracStr[:maxFracDigits]
 	}
 	if len(fracStr) == 0 {
@@ -309,26 +309,6 @@ func tryParseFractionalUnixTimestamp(intStr, fracStr string) (int64, bool) {
 	return n + frac, true
 }
 
-func multiplyByDecimalExp(n int64, decimalExp int64) (int64, bool) {
-	if decimalExp < 0 {
-		return 0, false
-	}
-	if decimalExp >= int64(len(decimalMultipliers)) {
-		return 0, false
-	}
-	if decimalExp == 0 {
-		return n, true
-	}
-
-	m := decimalMultipliers[decimalExp]
-
-	if n >= 0 && n > math.MaxInt64/m || n < 0 && n < math.MinInt64/m {
-		return 0, false
-	}
-
-	return n * m, true
-}
-
 var decimalMultipliers = [...]int64{0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18}
 
 const (
@@ -369,3 +349,12 @@ func tryParseInt64(s string) (int64, bool) {
 	}
 	return n, true
 }
+
+func isDecimalString(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] < '0' || s[i] > '9' {
+			return false
+		}
+	}
+	return true
+}

lib/timeutil/time_test.go

@@ -76,6 +76,7 @@ func TestTryParseUnixTimestamp_Success(t *testing.T) {
 	f("-1.23456789e9", -1234567890_000_000_000)
 	f("1.234567890123456789e18", 1234567890_123_456_789)
 	f("-1.234567890123456789e18", -1234567890_123_456_789)
+	f("0.0000000001e19", 1000000000_000_000_000)
 	f("0.23456789e9", 234567890_000_000_000)
 	f("123.456789123e9", 123456789_123_000_000)
 	f("-1234.5678912e9", -1234567891_200_000_000)
@@ -99,7 +100,19 @@ func TestTryParseUnixTimestamp_Success(t *testing.T) {
 	f("1.23456789e9", 1234567890_000_000_000)   // exponent consumes all frac digits (integer result)
 	f("1.23e1", 12_300_000_000)                 // == 12.3
 	f("1.234e0", 1_234_000_000)                 // == 1.234
+	f("-0.1e1", -1_000_000_000)                 // == -1
 	f("1234567890123456789.0e0", 1234567890_123_456_789)
+	f("1000e-1", 100_000_000_000)
+	f("1000E-1", 100_000_000_000)
+	f("-1000e-1", -100_000_000_000)
+	f("1e-1", 100_000_000)
+	f("-1e-1", -100_000_000)
+	f("1000.01e-1", 100_001_000_000)
+	f("-1000.01e-1", -100_001_000_000)
+	f("1.2E-1", 120_000_000)
+	f("1.2345678901e-1", 123_456_789)
+	f("0.12345678901", 123_456_789)
+	f("1.2345678901234567890123e-1", 123_456_789)
 
 }
 
@@ -138,7 +151,8 @@ func TestTryParseUnixTimestamp_Failure(t *testing.T) {
 	f("1.3e123456789090123")
 
 	// negative decimal exponent
-	f("1E-1")
+	f("1e-9223372036854775808")
+	f("1e-123456789090123")
 	f("1.3e-123456789090123")
 
 }
@@ -164,6 +178,8 @@ func TestParseTimeAtSuccess(t *testing.T) {
 	f("1562529662.678", now, 1562529662_678_000_000)
 	f("1562529662.678123", now, 1562529662_678_123_000)
 	f("1562529662.678123456", now, 1562529662_678_123_456)
+	f("1000e-1", now, 100_000_000_000)
+	f("1000.01e-1", now, 100_001_000_000)
 
 	// unix timestamp in milliseconds
 	f("1562529662678", now, 1562529662_678_000_000)

lib/writeconcurrencylimiter/concurrencylimiter.go

@@ -10,16 +10,18 @@ import (
 	"time"
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/flagutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/httpserver"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/timerpool"
 	"github.com/VictoriaMetrics/metrics"
 )
 
 var (
-	maxConcurrentInserts = flag.Int("maxConcurrentInserts", 2*cgroup.AvailableCPUs(), "The maximum number of concurrent insert requests. "+
-		"Set higher value when clients send data over slow networks. "+
-		"Default value depends on the number of available CPU cores. It should work fine in most cases since it minimizes resource usage. "+
-		"See also -insert.maxQueueDuration")
+	maxConcurrentInserts = flagutil.NewIntWithDynamicDefault("maxConcurrentInserts", 2*cgroup.AvailableCPUs(), "2*cgroup.AvailableCPUs()",
+		"The maximum number of concurrent insert requests. "+
+			"Set higher value when clients send data over slow networks. "+
+			"Default value depends on the number of available CPU cores. It should work fine in most cases since it minimizes resource usage. "+
+			"See also -insert.maxQueueDuration")
 	maxQueueDuration = flag.Duration("insert.maxQueueDuration", time.Minute, "The maximum duration to wait in the queue when -maxConcurrentInserts "+
 		"concurrent insert requests are executed")
 )