Loki: Run queries in parallel behind lokiRunQueriesInParallel feature toggle (#74064)

* issue loki queries in parallel so total query time is only the slowest query rather than the sum of all query times.

* Fix lint

* Add running of queries in parallel behind feature toggle to test the functonality before release

* Add span end

* Move shared logic to separate function

* Add logging and tracing around running of all queries

---------

Co-authored-by: Ivana Huckova <ivana.huckova@gmail.com>

pkg/services/featuremgmt/registry.go

@@ -737,6 +737,13 @@ var (
 			FrontendOnly: false,
 			Owner:        grafanaPluginsPlatformSquad,
 		},
+		{
+			Name:         "lokiRunQueriesInParallel",
+			Description:  "Enables running Loki queries in parallel",
+			Stage:        FeatureStagePrivatePreview,
+			FrontendOnly: false,
+			Owner:        grafanaObservabilityLogsSquad,
+		},
 		{
 			Name:         "wargamesTesting",
 			Description:  "Placeholder feature flag for internal testing",

pkg/services/featuremgmt/toggles_gen.csv

@@ -105,5 +105,6 @@ reportingRetries,preview,@grafana/sharing-squad,false,false,true,false
 newBrowseDashboards,preview,@grafana/grafana-frontend-platform,false,false,false,true
 sseGroupByDatasource,experimental,@grafana/observability-metrics,false,false,false,false
 requestInstrumentationStatusSource,experimental,@grafana/plugins-platform-backend,false,false,false,false
+lokiRunQueriesInParallel,privatePreview,@grafana/observability-logs,false,false,false,false
 wargamesTesting,experimental,@grafana/hosted-grafana-team,false,false,false,false
 alertingInsights,experimental,@grafana/alerting-squad,false,false,false,true

pkg/services/featuremgmt/toggles_gen.go

@@ -431,6 +431,10 @@ const (
 	// Include a status source label for request metrics and logs
 	FlagRequestInstrumentationStatusSource = "requestInstrumentationStatusSource"
 
+	// FlagLokiRunQueriesInParallel
+	// Enables running Loki queries in parallel
+	FlagLokiRunQueriesInParallel = "lokiRunQueriesInParallel"
+
 	// FlagWargamesTesting
 	// Placeholder feature flag for internal testing
 	FlagWargamesTesting = "wargamesTesting"