querier: Remove max concurrency reference to query-frontend (grafana#…

…3678)

* querier: Remove max concurrency reference to query-frontend

Remove reference to query-frontend for flag -querier.max-concurrent,
since it's not used by the query-frontend any longer.

Also improve the -querier.max-concurrent help text a bit.

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>
Co-authored-by: Marco Pracucci <marco@pracucci.com>

cmd/mimir/config-descriptor.json

@@ -1863,7 +1863,7 @@
           "kind": "field",
           "name": "max_concurrent",
           "required": false,
-          "desc": "The maximum number of concurrent queries. This config option should be set on query-frontend too when query sharding is enabled.",
+          "desc": "The number of workers running in each querier process. This setting limits the maximum number of concurrent queries in each querier.",
           "fieldValue": null,
           "fieldDefaultValue": 20,
           "fieldFlag": "querier.max-concurrent",

cmd/mimir/help-all.txt.tmpl

@@ -1250,7 +1250,7 @@ Usage of ./cmd/mimir/mimir:
   -querier.lookback-delta duration
     	Time since the last sample after which a time series is considered stale and ignored by expression evaluations. This config option should be set on query-frontend too when query sharding is enabled. (default 5m0s)
   -querier.max-concurrent int
-    	The maximum number of concurrent queries. This config option should be set on query-frontend too when query sharding is enabled. (default 20)
+    	The number of workers running in each querier process. This setting limits the maximum number of concurrent queries in each querier. (default 20)
   -querier.max-fetched-chunk-bytes-per-query int
     	The maximum size of all chunks in bytes that a query can fetch from each ingester and storage. This limit is enforced in the querier and ruler. 0 to disable.
   -querier.max-fetched-chunks-per-query int

cmd/mimir/help.txt.tmpl

@@ -382,7 +382,7 @@ Usage of ./cmd/mimir/mimir:
   -querier.label-values-max-cardinality-label-names-per-request int
     	Maximum number of label names allowed to be queried in a single /api/v1/cardinality/label_values API call. (default 100)
   -querier.max-concurrent int
-    	The maximum number of concurrent queries. This config option should be set on query-frontend too when query sharding is enabled. (default 20)
+    	The number of workers running in each querier process. This setting limits the maximum number of concurrent queries in each querier. (default 20)
   -querier.max-fetched-chunk-bytes-per-query int
     	The maximum size of all chunks in bytes that a query can fetch from each ingester and storage. This limit is enforced in the querier and ruler. 0 to disable.
   -querier.max-fetched-chunks-per-query int

docs/sources/mimir/operators-guide/configure/reference-configuration-parameters/index.md

@@ -960,8 +960,8 @@ store_gateway_client:
 # CLI flag: -querier.shuffle-sharding-ingesters-enabled
 [shuffle_sharding_ingesters_enabled: <boolean> | default = true]
 
-# The maximum number of concurrent queries. This config option should be set on
-# query-frontend too when query sharding is enabled.
+# The number of workers running in each querier process. This setting limits the
+# maximum number of concurrent queries in each querier.
 # CLI flag: -querier.max-concurrent
 [max_concurrent: <int> | default = 20]
 

pkg/querier/engine/config.go

@@ -39,7 +39,7 @@ func (cfg *Config) RegisterFlags(f *flag.FlagSet) {
 		return help + "This config option should be set on query-frontend too when query sharding is enabled."
 	}
 
-	f.IntVar(&cfg.MaxConcurrent, "querier.max-concurrent", 20, sharedWithQueryFrontend("The maximum number of concurrent queries."))
+	f.IntVar(&cfg.MaxConcurrent, "querier.max-concurrent", 20, "The number of workers running in each querier process. This setting limits the maximum number of concurrent queries in each querier.")
 	f.DurationVar(&cfg.Timeout, "querier.timeout", 2*time.Minute, sharedWithQueryFrontend("The timeout for a query.")+" This also applies to queries evaluated by the ruler (internally or remotely).")
 	f.IntVar(&cfg.MaxSamples, "querier.max-samples", 50e6, sharedWithQueryFrontend("Maximum number of samples a single query can load into memory."))
 	f.DurationVar(&cfg.DefaultEvaluationInterval, "querier.default-evaluation-interval", time.Minute, sharedWithQueryFrontend("The default evaluation interval or step size for subqueries."))