Add flag for enabling and disabling OOO native histogram ingestion

Signed-off-by: Carrie Edwards <edwrdscarrie@gmail.com>

cmd/prometheus/main.go

@@ -228,6 +228,9 @@ func (c *flagConfig) setFeatureListOptions(logger log.Logger) error {
 				config.DefaultConfig.GlobalConfig.ScrapeProtocols = config.DefaultProtoFirstScrapeProtocols
 				config.DefaultGlobalConfig.ScrapeProtocols = config.DefaultProtoFirstScrapeProtocols
 				level.Info(logger).Log("msg", "Experimental native histogram support enabled. Changed default scrape_protocols to prefer PrometheusProto format.", "global.scrape_protocols", fmt.Sprintf("%v", config.DefaultGlobalConfig.ScrapeProtocols))
+			case "ooo-native-histograms":
+				c.tsdb.EnableOOONativeHistograms = true
+				level.Info(logger).Log("msg", "Experimental out-of-order native histogram ingestion enabled. This will only take effect if OutOfOrderTimeWindow is > 0 and if EnableNativeHistograms = true")
 			case "created-timestamp-zero-ingestion":
 				c.scrape.EnableCreatedTimestampZeroIngestion = true
 				// Change relevant global variables. Hacky, but it's hard to pass a new option or default to unmarshallers.
@@ -1715,6 +1718,7 @@ type tsdbOptions struct {
 	MaxExemplars                   int64
 	EnableMemorySnapshotOnShutdown bool
 	EnableNativeHistograms         bool
+	EnableOOONativeHistograms      bool
 }
 
 func (opts tsdbOptions) ToTSDBOptions() tsdb.Options {
@@ -1734,6 +1738,7 @@ func (opts tsdbOptions) ToTSDBOptions() tsdb.Options {
 		MaxExemplars:                   opts.MaxExemplars,
 		EnableMemorySnapshotOnShutdown: opts.EnableMemorySnapshotOnShutdown,
 		EnableNativeHistograms:         opts.EnableNativeHistograms,
+		EnableOOONativeHistograms:      opts.EnableOOONativeHistograms,
 		OutOfOrderTimeWindow:           opts.OutOfOrderTimeWindow,
 		EnableOverlappingCompaction:    true,
 	}

storage/interface.go

@@ -43,6 +43,7 @@ var (
 	ErrExemplarLabelLength         = fmt.Errorf("label length for exemplar exceeds maximum of %d UTF-8 characters", exemplar.ExemplarMaxLabelSetLength)
 	ErrExemplarsDisabled           = fmt.Errorf("exemplar storage is disabled or max exemplars is less than or equal to 0")
 	ErrNativeHistogramsDisabled    = fmt.Errorf("native histograms are disabled")
+	ErrOOONativeHistogramsDisabled = fmt.Errorf("out-of-order native histogram ingestion is disabled")
 
 	// ErrOutOfOrderCT indicates failed append of CT to the storage
 	// due to CT being older the then newer sample.

tsdb/db.go

@@ -170,6 +170,12 @@ type Options struct {
 	// EnableNativeHistograms enables the ingestion of native histograms.
 	EnableNativeHistograms bool
 
+	// EnableOOONativeHistograms enables the ingestion of OOO native histograms.
+	// It will only take effect if EnableNativeHistograms is set to true and the
+	// OutOfOrderTimeWindow is > 0. This flag will be removed after testing of
+	// OOO Native Histogram ingestion is complete.
+	EnableOOONativeHistograms bool
+
 	// OutOfOrderTimeWindow specifies how much out of order is allowed, if any.
 	// This can change during run-time, so this value from here should only be used
 	// while initialising.
@@ -936,6 +942,7 @@ func open(dir string, l log.Logger, r prometheus.Registerer, opts *Options, rngs
 	headOpts.MaxExemplars.Store(opts.MaxExemplars)
 	headOpts.EnableMemorySnapshotOnShutdown = opts.EnableMemorySnapshotOnShutdown
 	headOpts.EnableNativeHistograms.Store(opts.EnableNativeHistograms)
+	headOpts.EnableOOONativeHistograms.Store(opts.EnableOOONativeHistograms)
 	headOpts.OutOfOrderTimeWindow.Store(opts.OutOfOrderTimeWindow)
 	headOpts.OutOfOrderCapMax.Store(opts.OutOfOrderCapMax)
 	headOpts.EnableSharding = opts.EnableSharding
@@ -1156,6 +1163,16 @@ func (db *DB) DisableNativeHistograms() {
 	db.head.DisableNativeHistograms()
 }
 
+// EnableOOONativeHistograms enables the ingestion of out-of-order native histograms.
+func (db *DB) EnableOOONativeHistograms() {
+	db.head.EnableOOONativeHistograms()
+}
+
+// DisableOOONativeHistograms disables the ingestion of out-of-order native histograms.
+func (db *DB) DisableOOONativeHistograms() {
+	db.head.DisableOOONativeHistograms()
+}
+
 // dbAppender wraps the DB's head appender and triggers compactions on commit
 // if necessary.
 type dbAppender struct {

tsdb/head.go

@@ -149,6 +149,11 @@ type HeadOptions struct {
 	// EnableNativeHistograms enables the ingestion of native histograms.
 	EnableNativeHistograms atomic.Bool
 
+	// EnableOOONativeHistograms enables the ingestion of OOO native histograms.
+	// It will only take effect if EnableNativeHistograms is set to true and the
+	// OutOfOrderTimeWindow is > 0
+	EnableOOONativeHistograms atomic.Bool
+
 	// EnableCreatedTimestampZeroIngestion enables the ingestion of the created timestamp as a synthetic zero sample.
 	// See: https://github.com/prometheus/proposals/blob/main/proposals/2023-06-13_created-timestamp.md
 	EnableCreatedTimestampZeroIngestion bool
@@ -1035,6 +1040,16 @@ func (h *Head) DisableNativeHistograms() {
 	h.opts.EnableNativeHistograms.Store(false)
 }
 
+// EnableOOONativeHistograms enables the ingestion of out-of-order native histograms.
+func (h *Head) EnableOOONativeHistograms() {
+	h.opts.EnableOOONativeHistograms.Store(true)
+}
+
+// DisableOOONativeHistograms disables the ingestion of out-of-order native histograms.
+func (h *Head) DisableOOONativeHistograms() {
+	h.opts.EnableOOONativeHistograms.Store(false)
+}
+
 // PostingsCardinalityStats returns highest cardinality stats by label and value names.
 func (h *Head) PostingsCardinalityStats(statsByLabelName string, limit int) *index.PostingsStats {
 	cacheKey := statsByLabelName + ";" + strconv.Itoa(limit)