Adjust flag

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

cmd/prometheus/main.go

@@ -239,8 +239,8 @@ func main() {
 	a.Flag("rules.alert.resend-delay", "Minimum amount of time to wait before resending an alert to Alertmanager.").
 		Default("1m").SetValue(&cfg.resendDelay)
 
-	a.Flag("scrape.timestamp-tolerance", "Adjust scrape timestamps by up to this amount to align them to the intended schedule. Experimental.").
-		Hidden().Default("2ms").DurationVar(&scrape.ScrapeTimestampTolerance)
+	a.Flag("scrape.adjust-timestamps", "Adjust scrape timestamps by up to 2ms to align them to the intended schedule. Experimental.").
+		Hidden().Default("true").BoolVar(&scrape.AlignScrapeTimestamps)
 
 	a.Flag("alertmanager.notification-queue-capacity", "The capacity of the queue for pending Alertmanager notifications.").
 		Default("10000").IntVar(&cfg.notifier.QueueCapacity)

scrape/scrape.go

@@ -50,7 +50,10 @@ import (
 // Temporary tolerance for scrape appends timestamps alignment, to enable better
 // compression at the TSDB level.
 // See https://github.com/prometheus/prometheus/issues/7846
-var ScrapeTimestampTolerance = 2 * time.Millisecond
+const scrapeTimestampTolerance = 2 * time.Millisecond
+
+// Enable or disable the tolerance for scrape described above.
+var AlignScrapeTimestamps = true
 
 var errNameLabelMandatory = fmt.Errorf("missing metric name (%s label)", labels.MetricName)
 
@@ -1009,14 +1012,14 @@ mainLoop:
 		// increase in TSDB.
 		// See https://github.com/prometheus/prometheus/issues/7846
 		scrapeTime := time.Now()
-		if interval > 100*ScrapeTimestampTolerance {
+		if AlignScrapeTimestamps && interval > 100*scrapeTimestampTolerance {
 			// For some reason, a tick might have been skipped, in which case we
 			// would call alignedScrapeTime.Add(interval) multiple times.
 			for scrapeTime.Sub(alignedScrapeTime) >= interval {
 				alignedScrapeTime = alignedScrapeTime.Add(interval)
 			}
 			// Align the scrape time if we are in the tolerance boundaries.
-			if scrapeTime.Sub(alignedScrapeTime) <= ScrapeTimestampTolerance {
+			if scrapeTime.Sub(alignedScrapeTime) <= scrapeTimestampTolerance {
 				scrapeTime = alignedScrapeTime
 			}
 		}