improve default config values

CHANGELOG.md

@@ -30,6 +30,7 @@
 * [4942](https://github.com/grafana/loki/pull/4942) **cyriltovena**: Allow to disable HTTP/2 for GCS.
 * [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
 
 # 2.4.1 (2021/11/07)
 

docs/sources/configuration/_index.md

@@ -276,11 +276,11 @@ The `querier` block configures the Loki Querier.
 # Maximum lookback beyond which queries are not sent to ingester.
 # 0 means all queries are sent to ingester.
 # CLI flag: -querier.query-ingesters-within
-[query_ingesters_within: <duration> | default = 0s]
+[query_ingesters_within: <duration> | default = 3h]
 
 # The maximum number of concurrent queries allowed.
 # CLI flag: -querier.max-concurrent
-[max_concurrent: <int> | default = 20]
+[max_concurrent: <int> | default = 10]
 
 # Only query the store, do not attempt to query any ingesters,
 # useful for running a standalone querier pool opearting only against stored data.
@@ -396,7 +396,7 @@ results_cache:
 # Perform query parallelisations based on storage sharding configuration and
 # query ASTs. This feature is supported only by the chunks storage engine.
 # CLI flag: -querier.parallelise-shardable-queries
-[parallelise_shardable_queries: <boolean> | default = false]
+[parallelise_shardable_queries: <boolean> | default = true]
 ```
 
 ## ruler
@@ -1073,7 +1073,7 @@ lifecycler:
 # The maximum duration of a timeseries chunk in memory. If a timeseries runs for longer than this,
 # the current chunk will be flushed to the store and a new chunk created.
 # CLI flag: -ingester.max-chunk-age
-[max_chunk_age: <duration> | default = 1h]
+[max_chunk_age: <duration> | default = 2h]
 
 # How far in the past an ingester is allowed to query the store for data.
 # This is only useful for running multiple Loki binaries with a shared ring
@@ -2167,7 +2167,7 @@ The `limits_config` block configures global and per-tenant limits in Loki.
 # to avoid queriers downloading and processing the same chunks. This also
 # determines how cache keys are chosen when result caching is enabled
 # CLI flag: -querier.split-queries-by-interval
-[split_queries_by_interval: <duration> | default = 0s]
+[split_queries_by_interval: <duration> | default = 30m]
 ```
 
 ### grpc_client_config

docs/sources/upgrading/_index.md

@@ -49,6 +49,14 @@ The response body has the following schema:
 }
 ```
 
+#### Changes to default configuration values
+
+* `parallelise_shardable_queries` under the Query Range config now defaults to `true`, it was `false`.
+* `split_queries_by_interval` under the Query Range config now defaults to `30m`, it was `0s`.
+* `max_chunk_age` for the Ingester now defaults to `2h` instead of `1h`.
+* `query_ingesters_within` under the Queier config now defaults to `3h`, it was previously set to 0, meaning always query ingesters.
+* `max_concurrent` under the Querier config now defaults to `10` instead of `20`, since is should be the same as the Frontend Worker's `parallelism` setting (which is `10`).
+
 ### Promtail
 
 #### `gcplog` labels have changed

pkg/ingester/ingester.go

@@ -106,7 +106,7 @@ func (cfg *Config) RegisterFlags(f *flag.FlagSet) {
 	f.DurationVar(&cfg.SyncPeriod, "ingester.sync-period", 0, "How often to cut chunks to synchronize ingesters.")
 	f.Float64Var(&cfg.SyncMinUtilization, "ingester.sync-min-utilization", 0, "Minimum utilization of chunk when doing synchronization.")
 	f.IntVar(&cfg.MaxReturnedErrors, "ingester.max-ignored-stream-errors", 10, "Maximum number of ignored stream errors to return. 0 to return all errors.")
-	f.DurationVar(&cfg.MaxChunkAge, "ingester.max-chunk-age", time.Hour, "Maximum chunk age before flushing.")
+	f.DurationVar(&cfg.MaxChunkAge, "ingester.max-chunk-age", 2*time.Hour, "Maximum chunk age before flushing.")
 	f.DurationVar(&cfg.QueryStoreMaxLookBackPeriod, "ingester.query-store-max-look-back-period", 0, "How far back should an ingester be allowed to query the store for data, for use only with boltdb-shipper index and filesystem object store. -1 for infinite.")
 	f.BoolVar(&cfg.AutoForgetUnhealthy, "ingester.autoforget-unhealthy", false, "Enable to remove unhealthy ingesters from the ring after `ring.kvstore.heartbeat_timeout`")
 	f.IntVar(&cfg.IndexShards, "ingester.index-shards", index.DefaultIndexShards, "Shard factor used in the ingesters for the in process reverse index. This MUST be evenly divisible by ALL schema shard factors or Loki will not start.")

pkg/loki/loki.go

@@ -105,7 +105,7 @@ func (c *Config) RegisterFlags(f *flag.FlagSet) {
 	c.Frontend.RegisterFlags(f)
 	c.Ruler.RegisterFlags(f)
 	c.Worker.RegisterFlags(f)
-	c.QueryRange.RegisterFlags(f)
+	c.registerQueryRangeFlagsWithChangedDefaultValues(f)
 	c.RuntimeConfig.RegisterFlags(f)
 	c.MemberlistKV.RegisterFlags(f)
 	c.Tracing.RegisterFlags(f)
@@ -134,6 +134,28 @@ func (c *Config) registerServerFlagsWithChangedDefaultValues(fs *flag.FlagSet) {
 	})
 }
 
+func (c *Config) registerQueryRangeFlagsWithChangedDefaultValues(fs *flag.FlagSet) {
+	throwaway := flag.NewFlagSet("throwaway", flag.PanicOnError)
+	// NB: We can remove this after removing Loki's dependency on Cortex and bringing in the queryrange.Config.
+	// That will let us change the defaults there rather than include wrapper functions like this one.
+	// Register to throwaway flags first. Default values are remembered during registration and cannot be changed,
+	// but we can take values from throwaway flag set and reregister into supplied flags with new default values.
+	c.QueryRange.RegisterFlags(throwaway)
+
+	throwaway.VisitAll(func(f *flag.Flag) {
+		// Ignore errors when setting new values. We have a test to verify that it works.
+		switch f.Name {
+		case "querier.split-queries-by-interval":
+			_ = f.Value.Set("30m")
+
+		case "querier.parallelise-shardable-queries":
+			_ = f.Value.Set("true")
+		}
+
+		fs.Var(f.Value, f.Name, f.Usage)
+	})
+}
+
 // Clone takes advantage of pass-by-value semantics to return a distinct *Config.
 // This is primarily used to parse a different flag set without mutating the original *Config.
 func (c *Config) Clone() flagext.Registerer {

pkg/querier/querier.go

@@ -57,8 +57,8 @@ func (cfg *Config) RegisterFlags(f *flag.FlagSet) {
 	f.DurationVar(&cfg.TailMaxDuration, "querier.tail-max-duration", 1*time.Hour, "Limit the duration for which live tailing request would be served")
 	f.DurationVar(&cfg.QueryTimeout, "querier.query-timeout", 1*time.Minute, "Timeout when querying backends (ingesters or storage) during the execution of a query request")
 	f.DurationVar(&cfg.ExtraQueryDelay, "querier.extra-query-delay", 0, "Time to wait before sending more than the minimum successful query requests.")
-	f.DurationVar(&cfg.QueryIngestersWithin, "querier.query-ingesters-within", 0, "Maximum lookback beyond which queries are not sent to ingester. 0 means all queries are sent to ingester.")
-	f.IntVar(&cfg.MaxConcurrent, "querier.max-concurrent", 20, "The maximum number of concurrent queries.")
+	f.DurationVar(&cfg.QueryIngestersWithin, "querier.query-ingesters-within", 3*time.Hour, "Maximum lookback beyond which queries are not sent to ingester. 0 means all queries are sent to ingester.")
+	f.IntVar(&cfg.MaxConcurrent, "querier.max-concurrent", 10, "The maximum number of concurrent queries.")
 	f.BoolVar(&cfg.QueryStoreOnly, "querier.query-store-only", false, "Queriers should only query the store and not try to query any ingesters")
 }