Merge pull request #5 from codesome/num-series-read-only

NumSeries in Meta() of Head

head.go

@@ -65,6 +65,7 @@ type Head struct {
  logger log.Logger
  appendPool sync.Pool
  bytesPool sync.Pool
+ numSeries uint64
 
  minTime, maxTime int64 // Current min and max of the samples included in the head.
  minValidTime int64 // Mint allowed to be added to the head. It shouldn't be lower than the maxt of the last persisted block.
@@ -85,7 +86,7 @@ type Head struct {
 
 type headMetrics struct {
  activeAppenders prometheus.Gauge
- series prometheus.Gauge
+ series prometheus.GaugeFunc
  seriesCreated prometheus.Counter
  seriesRemoved prometheus.Counter
  seriesNotFound prometheus.Counter
@@ -113,9 +114,11 @@ func newHeadMetrics(h *Head, r prometheus.Registerer) *headMetrics {
  Name: "prometheus_tsdb_head_active_appenders",
  Help: "Number of currently active appender transactions",
  })
- m.series = prometheus.NewGauge(prometheus.GaugeOpts{
+ m.series = prometheus.NewGaugeFunc(prometheus.GaugeOpts{
  Name: "prometheus_tsdb_head_series",
  Help: "Total number of series in the head block.",
+ }, func() float64 {
+ return float64(h.NumSeries())
  })
  m.seriesCreated = prometheus.NewCounter(prometheus.CounterOpts{
  Name: "prometheus_tsdb_head_series_created_total",
@@ -699,11 +702,18 @@ func (h *rangeHead) MaxTime() int64 {
  return h.maxt
 }
 
+func (h *rangeHead) NumSeries() uint64 {
+ return h.head.NumSeries()
+}
+
 func (h *rangeHead) Meta() BlockMeta {
  return BlockMeta{
  MinTime: h.MinTime(),
  MaxTime: h.MaxTime(),
  ULID: h.head.Meta().ULID,
+ Stats: BlockStats{
+ NumSeries: h.NumSeries(),
+ },
  }
 }
 
@@ -1031,9 +1041,10 @@ func (h *Head) gc() {
  seriesRemoved := len(deleted)
 
  h.metrics.seriesRemoved.Add(float64(seriesRemoved))
- h.metrics.series.Sub(float64(seriesRemoved))
  h.metrics.chunksRemoved.Add(float64(chunksRemoved))
  h.metrics.chunks.Sub(float64(chunksRemoved))
+ // Ref: https://golang.org/pkg/sync/atomic/#AddUint64
+ atomic.AddUint64(&h.numSeries, ^uint64(seriesRemoved-1))
 
  // Remove deleted series IDs from the postings lists.
  h.postings.Delete(deleted)
@@ -1110,6 +1121,11 @@ func (h *Head) chunksRange(mint, maxt int64) *headChunkReader {
  return &headChunkReader{head: h, mint: mint, maxt: maxt}
 }
 
+// NumSeries returns the number of active series in the head.
+func (h *Head) NumSeries() uint64 {
+ return atomic.LoadUint64(&h.numSeries)
+}
+
 // Meta returns meta information about the head.
 func (h *Head) Meta() BlockMeta {
  var id [16]byte
@@ -1118,6 +1134,9 @@ func (h *Head) Meta() BlockMeta {
  MinTime: h.MinTime(),
  MaxTime: h.MaxTime(),
  ULID: ulid.ULID(id),
+ Stats: BlockStats{
+ NumSeries: h.NumSeries(),
+ },
  }
 }
 
@@ -1367,8 +1386,8 @@ func (h *Head) getOrCreateWithID(id, hash uint64, lset labels.Labels) (*memSerie
  return s, false
  }
 
- h.metrics.series.Inc()
  h.metrics.seriesCreated.Inc()
+ atomic.AddUint64(&h.numSeries, 1)
 
  h.postings.Add(id, lset)