Expose prometheus_tsdb_lowest_timestamp metric (#363)

* Expose prometheus_tsdb_start_time_seconds metric Signed-off-by: Bob Shannon <[email protected]> * Search for block with smallest minTime Signed-off-by: Bob Shannon <[email protected]> * PR comments Signed-off-by: Bob Shannon <[email protected]> * PR comment: Make metric name more accurate Signed-off-by: Bob Shannon <[email protected]>
prometheus-junkyard · Sep 14, 2018 · cb7f320 · cb7f320
1 parent 9be8836
commit cb7f320
Showing 1 changed file with 13 additions and 0 deletions.
diff --git a/db.go b/db.go
@@ -125,6 +125,7 @@ type dbMetrics struct {
 	compactionsTriggered prometheus.Counter
 	cutoffs              prometheus.Counter
 	cutoffsFailed        prometheus.Counter
+	startTime            prometheus.GaugeFunc
 	tombCleanTimer       prometheus.Histogram
 }
 
@@ -172,6 +173,17 @@ func newDBMetrics(db *DB, r prometheus.Registerer) *dbMetrics {
 		Name: "prometheus_tsdb_retention_cutoffs_failures_total",
 		Help: "Number of times the database failed to cut off block data from disk.",
 	})
+	m.startTime = prometheus.NewGaugeFunc(prometheus.GaugeOpts{
+		Name: "prometheus_tsdb_lowest_timestamp",
+		Help: "Lowest timestamp value stored in the database.",
+	}, func() float64 {
+		db.mtx.RLock()
+		defer db.mtx.RUnlock()
+		if len(db.blocks) == 0 {
+			return float64(db.head.minTime)
+		}
+		return float64(db.blocks[0].meta.MinTime)
+	})
 	m.tombCleanTimer = prometheus.NewHistogram(prometheus.HistogramOpts{
 		Name: "prometheus_tsdb_tombstone_cleanup_seconds",
 		Help: "The time taken to recompact blocks to remove tombstones.",
@@ -186,6 +198,7 @@ func newDBMetrics(db *DB, r prometheus.Registerer) *dbMetrics {
 			m.cutoffs,
 			m.cutoffsFailed,
 			m.compactionsTriggered,
+			m.startTime,
 			m.tombCleanTimer,
 		)
 	}