receive: port expanded postings cache from Cortex (#7914)

Port expanded postings cache from Cortex. Huge kudos to @alanprot for
the implementation. I added a TODO item to convert our whole internal
caching infra to be promise based.

Signed-off-by: Giedrius Statkevičius <[email protected]>

Author: GiedriusS

cmd/thanos/receive.go

@@ -141,7 +141,10 @@ func runReceive(
 
 	level.Info(logger).Log("mode", receiveMode, "msg", "running receive")
 
-	multiTSDBOptions := []receive.MultiTSDBOption{}
+	multiTSDBOptions := []receive.MultiTSDBOption{
+		receive.WithHeadExpandedPostingsCacheSize(conf.headExpandedPostingsCacheSize),
+		receive.WithBlockExpandedPostingsCacheSize(conf.compactedBlocksExpandedPostingsCacheSize),
+	}
 	for _, feature := range *conf.featureList {
 		if feature == metricNamesFilter {
 			multiTSDBOptions = append(multiTSDBOptions, receive.WithMetricNameFilterEnabled())
@@ -886,6 +889,9 @@ type receiveConfig struct {
 	asyncForwardWorkerCount uint
 
 	featureList *[]string
+
+	headExpandedPostingsCacheSize            uint64
+	compactedBlocksExpandedPostingsCacheSize uint64
 }
 
 func (rc *receiveConfig) registerFlag(cmd extkingpin.FlagClause) {
@@ -996,6 +1002,9 @@ func (rc *receiveConfig) registerFlag(cmd extkingpin.FlagClause) {
 
 	cmd.Flag("tsdb.no-lockfile", "Do not create lockfile in TSDB data directory. In any case, the lockfiles will be deleted on next startup.").Default("false").BoolVar(&rc.noLockFile)
 
+	cmd.Flag("tsdb.head.expanded-postings-cache-size", "[EXPERIMENTAL] If non-zero, enables expanded postings cache for the head block.").Default("0").Uint64Var(&rc.headExpandedPostingsCacheSize)
+	cmd.Flag("tsdb.block.expanded-postings-cache-size", "[EXPERIMENTAL] If non-zero, enables expanded postings cache for compacted blocks.").Default("0").Uint64Var(&rc.compactedBlocksExpandedPostingsCacheSize)
+
 	cmd.Flag("tsdb.max-exemplars",
 		"Enables support for ingesting exemplars and sets the maximum number of exemplars that will be stored per tenant."+
 			" In case the exemplar storage becomes full (number of stored exemplars becomes equal to max-exemplars),"+

docs/components/receive.md

@@ -552,6 +552,12 @@ Flags:
                                  Allow overlapping blocks, which in turn enables
                                  vertical compaction and vertical query merge.
                                  Does not do anything, enabled all the time.
+      --tsdb.block.expanded-postings-cache-size=0
+                                 [EXPERIMENTAL] If non-zero, enables expanded
+                                 postings cache for compacted blocks.
+      --tsdb.head.expanded-postings-cache-size=0
+                                 [EXPERIMENTAL] If non-zero, enables expanded
+                                 postings cache for the head block.
       --tsdb.max-exemplars=0     Enables support for ingesting exemplars and
                                  sets the maximum number of exemplars that will
                                  be stored per tenant. In case the exemplar