app/{graphite,netstorage,prometheus}: fix graphite search tags api limits, remove redudant limit from SeriesHandler handler (#4352)

* app/{graphite,netstorage,prometheus}: fix graphite search tags api limits, remove unused limit from SeriesHandler handler,

* app/{graphite,netstorage,prometheus}: use search.maxTagValues for Graphite

* app/{graphite,netstorage,prometheus}: update CHANGELOG.md

* app/{graphite,netstorage,prometheus}: use own flags for Graphite API

* app/{graphite,netstorage,prometheus}: cleanup

* app/{graphite,netstorage,prometheus}: cleanup

* app/{graphite,netstorage,prometheus}: update docs

---------

Co-authored-by: Nikolay <nik@victoriametrics.com>

README.md

@@ -2498,6 +2498,10 @@ Pass `-help` to VictoriaMetrics in order to see the list of supported command-li
      The maximum number of time series, which can be returned from /federate. This option allows limiting memory usage (default 1000000)
   -search.maxGraphiteSeries int
      The maximum number of time series, which can be scanned during queries to Graphite Render API. See https://docs.victoriametrics.com/#graphite-render-api-usage (default 300000)
+  -search.maxGraphiteTagKeys int
+     The maximum number of tag keys returned from Graphite /tags, /tags/autoComplete/*, /tags/findSeries API (default 100000)
+  -search.maxGraphiteTagValues int
+     The maximum number of tag values returned Graphite /tags/<tag_name> API (default 100000) 
   -search.maxLookback duration
      Synonym to -search.lookback-delta from Prometheus. The value is dynamically detected from interval between time series datapoints if not set. It can be overridden on per-query basis via max_lookback arg. See also '-search.maxStalenessInterval' flag, which has the same meaning due to historical reasons
   -search.maxMemoryPerQuery size

app/vmselect/graphite/tags_api.go

@@ -1,6 +1,7 @@
 package graphite
 
 import (
+	"flag"
 	"fmt"
 	"net/http"
 	"regexp"
@@ -18,6 +19,11 @@ import (
 	"github.com/VictoriaMetrics/metrics"
 )
 
+var (
+	maxGraphiteTagKeysPerSearch   = flag.Int("search.maxGraphiteTagKeys", 100e3, "The maximum number of tag keys returned from Graphite /tags, /tags/autoComplete/*, /tags/findSeries API")
+	maxGraphiteTagValuesPerSearch = flag.Int("search.maxGraphiteTagValues", 100e3, "The maximum number of tag values returned Graphite /tags/<tag_name> API")
+)
+
 // TagsDelSeriesHandler implements /tags/delSeries handler.
 //
 // See https://graphite.readthedocs.io/en/stable/tags.html#removing-series-from-the-tagdb
@@ -182,13 +188,13 @@ func TagsAutoCompleteValuesHandler(startTime time.Time, w http.ResponseWriter, r
 		// Escape special chars in tagPrefix as Graphite does.
 		// See https://github.com/graphite-project/graphite-web/blob/3ad279df5cb90b211953e39161df416e54a84948/webapp/graphite/tags/base.py#L228
 		filter := regexp.QuoteMeta(valuePrefix)
-		tagValues, err = netstorage.GraphiteTagValues(nil, tag, filter, limit, deadline)
+		tagValues, err = netstorage.GraphiteTagValues(nil, tag, filter, *maxGraphiteTagKeysPerSearch, deadline)
 		if err != nil {
 			return err
 		}
 	} else {
 		// Slow path: use netstorage.SearchMetricNames for applying `expr` filters.
-		sq, err := getSearchQueryForExprs(startTime, etfs, exprs, limit*10)
+		sq, err := getSearchQueryForExprs(startTime, etfs, exprs, *maxGraphiteTagKeysPerSearch)
 		if err != nil {
 			return err
 		}
@@ -269,13 +275,13 @@ func TagsAutoCompleteTagsHandler(startTime time.Time, w http.ResponseWriter, r *
 		// Escape special chars in tagPrefix as Graphite does.
 		// See https://github.com/graphite-project/graphite-web/blob/3ad279df5cb90b211953e39161df416e54a84948/webapp/graphite/tags/base.py#L181
 		filter := regexp.QuoteMeta(tagPrefix)
-		labels, err = netstorage.GraphiteTags(nil, filter, limit, deadline)
+		labels, err = netstorage.GraphiteTags(nil, filter, *maxGraphiteTagKeysPerSearch, deadline)
 		if err != nil {
 			return err
 		}
 	} else {
 		// Slow path: use netstorage.SearchMetricNames for applying `expr` filters.
-		sq, err := getSearchQueryForExprs(startTime, etfs, exprs, limit*10)
+		sq, err := getSearchQueryForExprs(startTime, etfs, exprs, *maxGraphiteTagKeysPerSearch)
 		if err != nil {
 			return err
 		}
@@ -343,7 +349,7 @@ func TagsFindSeriesHandler(startTime time.Time, w http.ResponseWriter, r *http.R
 	if err != nil {
 		return fmt.Errorf("cannot setup tag filters: %w", err)
 	}
-	sq, err := getSearchQueryForExprs(startTime, etfs, exprs, limit*10)
+	sq, err := getSearchQueryForExprs(startTime, etfs, exprs, *maxGraphiteTagKeysPerSearch)
 	if err != nil {
 		return err
 	}
@@ -411,11 +417,14 @@ func TagValuesHandler(startTime time.Time, tagName string, w http.ResponseWriter
 		return err
 	}
 	filter := r.FormValue("filter")
-	tagValues, err := netstorage.GraphiteTagValues(nil, tagName, filter, limit, deadline)
+	tagValues, err := netstorage.GraphiteTagValues(nil, tagName, filter, *maxGraphiteTagValuesPerSearch, deadline)
 	if err != nil {
 		return err
 	}
 
+	if limit > 0 && limit < len(tagValues) {
+		tagValues = tagValues[:limit]
+	}
 	w.Header().Set("Content-Type", "application/json")
 	bw := bufferedwriter.Get(w)
 	defer bufferedwriter.Put(bw)
@@ -439,11 +448,14 @@ func TagsHandler(startTime time.Time, w http.ResponseWriter, r *http.Request) er
 		return err
 	}
 	filter := r.FormValue("filter")
-	labels, err := netstorage.GraphiteTags(nil, filter, limit, deadline)
+	labels, err := netstorage.GraphiteTags(nil, filter, *maxGraphiteTagKeysPerSearch, deadline)
 	if err != nil {
 		return err
 	}
 
+	if limit > 0 && limit < len(labels) {
+		labels = labels[:limit]
+	}
 	w.Header().Set("Content-Type", "application/json")
 	bw := bufferedwriter.Get(w)
 	defer bufferedwriter.Put(bw)

app/vmselect/prometheus/prometheus.go

@@ -633,11 +633,7 @@ func SeriesHandler(qt *querytracer.Tracer, startTime time.Time, w http.ResponseW
 		return err
 	}
 
-	minLimit := *maxSeriesLimit
-	if limit > 0 && limit < *maxSeriesLimit {
-		minLimit = limit
-	}
-	sq := storage.NewSearchQuery(cp.start, cp.end, cp.filterss, minLimit)
+	sq := storage.NewSearchQuery(cp.start, cp.end, cp.filterss, *maxSeriesLimit)
 	metricNames, err := netstorage.SearchMetricNames(qt, sq, cp.deadline)
 	if err != nil {
 		return fmt.Errorf("cannot fetch time series for %q: %w", sq, err)

docs/CHANGELOG.md

@@ -25,6 +25,10 @@ The following tip changes can be tested by building VictoriaMetrics components f
 ## tip
 
 * BUGFIX: [vmalert](https://docs.victoriametrics.com/vmalert.html): fix nil map assignment panic in runtime introduced in this [change](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4341).
+* BUGFIX: add the following command-line flags, which can be used for limiting Graphite API calls: 
+  `--search.maxGraphiteTagKeys` for limiting the number of tag keys returned from Graphite `/tags`, `/tags/autoComplete/*`, `/tags/findSeries` API. 
+  `--search.maxGraphiteTagValues` for limiting the number of tag values returned Graphite `/tags/<tag_name>` API. 
+  Remove redundant limit from [Prometheus api/v1/series](https://docs.victoriametrics.com/Single-server-VictoriaMetrics.html#prometheus-querying-api-usage). See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4339).
 
 
 ## [v1.91.1](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.91.1)

docs/Cluster-VictoriaMetrics.md

@@ -1156,6 +1156,10 @@ Below is the output for `/path/to/vmselect -help`:
      The maximum number of time series, which can be returned from /federate. This option allows limiting memory usage (default 1000000)
   -search.maxGraphiteSeries int
      The maximum number of time series, which can be scanned during queries to Graphite Render API. See https://docs.victoriametrics.com/#graphite-render-api-usage (default 300000)
+  -search.maxGraphiteTagKeys int
+     The maximum number of tag keys returned from Graphite /tags, /tags/autoComplete/*, /tags/findSeries API (default 100000)
+  -search.maxGraphiteTagValues int
+     The maximum number of tag values returned Graphite /tags/<tag_name> API (default 100000)   
   -search.maxLookback duration
      Synonym to -search.lookback-delta from Prometheus. The value is dynamically detected from interval between time series datapoints if not set. It can be overridden on per-query basis via max_lookback arg. See also '-search.maxStalenessInterval' flag, which has the same meaining due to historical reasons
   -search.maxMemoryPerQuery size

docs/README.md

@@ -2501,6 +2501,10 @@ Pass `-help` to VictoriaMetrics in order to see the list of supported command-li
      The maximum number of time series, which can be returned from /federate. This option allows limiting memory usage (default 1000000)
   -search.maxGraphiteSeries int
      The maximum number of time series, which can be scanned during queries to Graphite Render API. See https://docs.victoriametrics.com/#graphite-render-api-usage (default 300000)
+  -search.maxGraphiteTagKeys int
+     The maximum number of tag keys returned from Graphite /tags, /tags/autoComplete/*, /tags/findSeries API (default 100000)
+  -search.maxGraphiteTagValues int
+     The maximum number of tag values returned Graphite /tags/<tag_name> API (default 100000)
   -search.maxLookback duration
      Synonym to -search.lookback-delta from Prometheus. The value is dynamically detected from interval between time series datapoints if not set. It can be overridden on per-query basis via max_lookback arg. See also '-search.maxStalenessInterval' flag, which has the same meaning due to historical reasons
   -search.maxMemoryPerQuery size

docs/Single-server-VictoriaMetrics.md

@@ -2509,6 +2509,10 @@ Pass `-help` to VictoriaMetrics in order to see the list of supported command-li
      The maximum number of time series, which can be returned from /federate. This option allows limiting memory usage (default 1000000)
   -search.maxGraphiteSeries int
      The maximum number of time series, which can be scanned during queries to Graphite Render API. See https://docs.victoriametrics.com/#graphite-render-api-usage (default 300000)
+  -search.maxGraphiteTagKeys int
+     The maximum number of tag keys returned from Graphite /tags, /tags/autoComplete/*, /tags/findSeries API (default 100000)
+  -search.maxGraphiteTagValues int
+     The maximum number of tag values returned Graphite /tags/<tag_name> API (default 100000)
   -search.maxLookback duration
      Synonym to -search.lookback-delta from Prometheus. The value is dynamically detected from interval between time series datapoints if not set. It can be overridden on per-query basis via max_lookback arg. See also '-search.maxStalenessInterval' flag, which has the same meaning due to historical reasons
   -search.maxMemoryPerQuery size