Default max_outstanding_per_tenant to 2048 (#5204)

* Default max_outstanding_per_tenant to 2048

* Update changelog

CHANGELOG.md

@@ -40,6 +40,7 @@
 * [4876](https://github.com/grafana/loki/pull/4876) **trevorwhitney**: Docs: add simple, scalable example using docker-compose
 * [4857](https://github.com/grafana/loki/pull/4857) **jordanrushing**: New schema v12 changes chunk key structure
 * [5077](https://github.com/grafana/loki/pull/5077) **trevorwhitney**: Change some default values for better out-of-the-box performance
+* [5204](https://github.com/grafana/loki/pull/5204) **trevorwhitney**: Default `max_outstanding_per_tenant` to `2048`
 
 # 2.4.1 (2021/11/07)
 

docs/sources/configuration/_index.md

@@ -338,7 +338,7 @@ The `frontend` block configures the Loki query-frontend.
 # Maximum number of outstanding requests per tenant per frontend; requests
 # beyond this error with HTTP 429.
 # CLI flag: -querier.max-outstanding-requests-per-tenant
-[max_outstanding_per_tenant: <int> | default = 100]
+[max_outstanding_per_tenant: <int> | default = 2048]
 
 # In the event a tenant is repeatedly sending queries that lead the querier to crash
 # or be killed due to an out-of-memory error, the crashed querier will be disconnected

pkg/lokifrontend/frontend/v1/frontend.go

@@ -35,7 +35,7 @@ type Config struct {
 
 // RegisterFlags adds the flags required to config this to the given FlagSet.
 func (cfg *Config) RegisterFlags(f *flag.FlagSet) {
-	f.IntVar(&cfg.MaxOutstandingPerTenant, "querier.max-outstanding-requests-per-tenant", 100, "Maximum number of outstanding requests per tenant per frontend; requests beyond this error with HTTP 429.")
+	f.IntVar(&cfg.MaxOutstandingPerTenant, "querier.max-outstanding-requests-per-tenant", 2048, "Maximum number of outstanding requests per tenant per frontend; requests beyond this error with HTTP 429.")
 	f.DurationVar(&cfg.QuerierForgetDelay, "query-frontend.querier-forget-delay", 0, "If a querier disconnects without sending notification about graceful shutdown, the query-frontend will keep the querier in the tenant's shard until the forget delay has passed. This feature is useful to reduce the blast radius when shuffle-sharding is enabled.")
 }