cleanup docs for query_store_for_labels_enabled config (#6156)

* cleanup docs for query_store_for_labels_enabled config

Signed-off-by: Ben Ye <[email protected]>

* update doc and mention the release

Signed-off-by: Ben Ye <[email protected]>

---------

Signed-off-by: Ben Ye <[email protected]>

Author: yeya24

docs/api/_index.md

@@ -355,9 +355,7 @@ GET,POST <prometheus-http-prefix>/api/v1/series
 GET,POST <legacy-http-prefix>/api/v1/series
 ```
 
-Find series by label matchers. Differently than Prometheus and due to scalability and performances reasons, if `-querier.query-store-for-labels-enabled` is not set or if `start` param is not specified, Cortex currently always fetches series from data stored in the ingesters.
-
-If `-querier.query-store-for-labels-enabled` is configured, Cortex also queries the long-term store with the *blocks* storage engine.
+Find series by label matchers. Starting from release v1.18.0, Cortex by default honors the `start` and `end` request parameters and fetches series from either ingester, store gateway or both. The special case is that if `start` param is not specified, Cortex currently fetches series from data stored in the ingesters.
 
 _For more information, please check out the Prometheus [series endpoint](https://prometheus.io/docs/prometheus/latest/querying/api/#finding-series-by-label-matchers) documentation._
 
@@ -372,7 +370,7 @@ GET,POST <prometheus-http-prefix>/api/v1/labels
 GET,POST <legacy-http-prefix>/api/v1/labels
 ```
 
-Get label names of ingested series. Differently than Prometheus and due to scalability and performances reasons, Cortex currently ignores the `start` and `end` request parameters and always fetches the label names from in-memory data stored in the ingesters. There is experimental support to query the long-term store with the *blocks* storage engine when `-querier.query-store-for-labels-enabled` is set.
+Get label names of ingested series. Starting from release v1.18.0, Cortex by default honors the `start` and `end` request parameters and fetches label names from either ingester, store gateway or both.
 
 _For more information, please check out the Prometheus [get label names](https://prometheus.io/docs/prometheus/latest/querying/api/#getting-label-names) documentation._
 
@@ -387,7 +385,7 @@ GET <prometheus-http-prefix>/api/v1/label/{name}/values
 GET <legacy-http-prefix>/api/v1/label/{name}/values
 ```
 
-Get label values for a given label name. Differently than Prometheus and due to scalability and performances reasons, Cortex currently ignores the `start` and `end` request parameters and always fetches the label values from in-memory data stored in the ingesters. There is experimental support to query the long-term store with the *blocks* storage engine when `-querier.query-store-for-labels-enabled` is set.
+Get label values for a given label name. Starting from release v1.18.0, Cortex by default honors the `start` and `end` request parameters and fetches label values from either ingester, store gateway or both.
 
 _For more information, please check out the Prometheus [get label values](https://prometheus.io/docs/prometheus/latest/querying/api/#querying-label-values) documentation._
 

docs/configuration/v1-guarantees.md

@@ -23,7 +23,6 @@ The Cortex maintainers commit to ensuring future version of Cortex can read data
 
 Cortex strives to be 100% API compatible with Prometheus (under `/prometheus/*` and `/api/prom/*`); any deviation from this is considered a bug, except:
 
-- For queries to the `/api/v1/series`, `/api/v1/labels` and `/api/v1/label/{name}/values` endpoints, query's time range is ignored and the data is always fetched from ingesters. There is experimental support to query the long-term store with the *blocks* storage engine when `-querier.query-store-for-labels-enabled` is set.
 - Additional API endpoints for creating, removing and modifying alerts and recording rules.
 - Additional API around pushing metrics (under `/api/push`).
 - Additional API endpoints for management of Cortex itself, such as the ring.  These APIs are not part of the any compatibility guarantees.
@@ -53,7 +52,6 @@ Currently experimental features are:
 - OpenStack Swift storage support.
 - Metric relabeling in the distributor.
 - Scalable query-frontend (when using query-scheduler)
-- Querying store for series, labels APIs (`-querier.query-store-for-labels-enabled`)
 - Ingester: do not unregister from ring on shutdown (`-ingester.unregister-on-shutdown=false`)
 - Distributor: do not extend writes on unhealthy ingesters (`-distributor.extend-writes=false`)
 - Tenant Deletion in Purger, for blocks storage.

docs/guides/limitations.md

@@ -35,7 +35,3 @@ All other characters are not safe to use. In particular, slashes `/` and whitesp
 ### Length
 
 The tenant ID length should not exceed 150 bytes/characters.
-
-## Query series and labels
-
-When running queries to the `/api/v1/series`, `/api/v1/labels` and `/api/v1/label/{name}/values` endpoints, query's time range is ignored and the data is always fetched from ingesters. There is experimental support to query the long-term store with the *blocks* storage engine when `-querier.query-store-for-labels-enabled` is set.

pkg/ingester/ingester_test.go

@@ -2731,7 +2731,7 @@ func Test_Ingester_MetricsForLabelMatchers(t *testing.T) {
 				{Labels: cortexpb.FromLabelsToLabelAdapters(fixtures[1].lbls)},
 			},
 		},
-		"should filter metrics by time range if queryStoreForLabels and queryIngestersWithin is enabled": {
+		"should filter metrics by time range if queryIngestersWithin is enabled": {
 			from: 99999,
 			to:   100001,
 			matchers: []*client.LabelMatchers{{

pkg/querier/querier_test.go

@@ -1411,7 +1411,6 @@ type mockStoreQuerier struct {
 // Select implements storage.Querier interface.
 // The bool passed is ignored because the series is always sorted.
 func (q *mockStoreQuerier) Select(ctx context.Context, _ bool, sp *storage.SelectHints, matchers ...*labels.Matcher) storage.SeriesSet {
-	// We will hit this for /series lookup when -querier.query-store-for-labels-enabled is set.
 	// If we don't skip here, it'll make /series lookups extremely slow as all the chunks will be loaded.
 	// That flag is only to be set with blocks storage engine, and this is a protective measure.
 	if sp != nil && sp.Func == "series" {