scorch stats MaxBatchIntroTime bug fix and more timing stats

Added timing stats for in-mem zap merging and file-based zap merging.

index/scorch/merge.go

@@ -179,9 +179,19 @@ func (s *Scorch) planMergeAtSnapshot(ourSnapshot *IndexSnapshot,
 			filename := zapFileName(newSegmentID)
 			s.markIneligibleForRemoval(filename)
 			path := s.path + string(os.PathSeparator) + filename
+
+			fileMergeZapStartTime := time.Now()
+
 			atomic.AddUint64(&s.stats.TotFileMergeZapBeg, 1)
 			newDocNums, err := zap.Merge(segmentsToMerge, docsToDrop, path, 1024)
 			atomic.AddUint64(&s.stats.TotFileMergeZapEnd, 1)
+
+			fileMergeZapTime := uint64(time.Since(fileMergeZapStartTime))
+			atomic.AddUint64(&s.stats.TotFileMergeZapTime, fileMergeZapTime)
+			if atomic.LoadUint64(&s.stats.MaxFileMergeZapTime) < fileMergeZapTime {
+				atomic.StoreUint64(&s.stats.MaxFileMergeZapTime, fileMergeZapTime)
+			}
+
 			if err != nil {
 				s.unmarkIneligibleForRemoval(filename)
 				atomic.AddUint64(&s.stats.TotFileMergePlanTasksErr, 1)
@@ -258,11 +268,20 @@ func (s *Scorch) mergeSegmentBases(snapshot *IndexSnapshot,
 
 	cr := zap.NewCountHashWriter(&br)
 
+	memMergeZapStartTime := time.Now()
+
 	atomic.AddUint64(&s.stats.TotMemMergeZapBeg, 1)
 	newDocNums, numDocs, storedIndexOffset, fieldsIndexOffset,
 		docValueOffset, dictLocs, fieldsInv, fieldsMap, err :=
 		zap.MergeToWriter(sbs, sbsDrops, chunkFactor, cr)
 	atomic.AddUint64(&s.stats.TotMemMergeZapEnd, 1)
+
+	memMergeZapTime := uint64(time.Since(memMergeZapStartTime))
+	atomic.AddUint64(&s.stats.TotMemMergeZapTime, memMergeZapTime)
+	if atomic.LoadUint64(&s.stats.MaxMemMergeZapTime) < memMergeZapTime {
+		atomic.StoreUint64(&s.stats.MaxMemMergeZapTime, memMergeZapTime)
+	}
+
 	if err != nil {
 		atomic.AddUint64(&s.stats.TotMemMergeErr, 1)
 		return 0, nil, 0, err

index/scorch/scorch.go

@@ -365,7 +365,7 @@ func (s *Scorch) prepareSegment(newSegment segment.Segment, ids []string,
 	introTime := uint64(time.Since(introStartTime))
 	atomic.AddUint64(&s.stats.TotBatchIntroTime, introTime)
 	if atomic.LoadUint64(&s.stats.MaxBatchIntroTime) < introTime {
-		atomic.AddUint64(&s.stats.MaxBatchIntroTime, introTime)
+		atomic.StoreUint64(&s.stats.MaxBatchIntroTime, introTime)
 	}
 
 	return err

index/scorch/stats.go

@@ -88,8 +88,10 @@ type Stats struct {
 	TotFileMergeSegmentsEmpty uint64
 	TotFileMergeSegments      uint64
 
-	TotFileMergeZapBeg uint64
-	TotFileMergeZapEnd uint64
+	TotFileMergeZapBeg  uint64
+	TotFileMergeZapEnd  uint64
+	TotFileMergeZapTime uint64
+	MaxFileMergeZapTime uint64
 
 	TotFileMergeIntroductions     uint64
 	TotFileMergeIntroductionsDone uint64
@@ -99,6 +101,8 @@ type Stats struct {
 	TotMemMergeDone     uint64
 	TotMemMergeZapBeg   uint64
 	TotMemMergeZapEnd   uint64
+	TotMemMergeZapTime  uint64
+	MaxMemMergeZapTime  uint64
 	TotMemMergeSegments uint64
 }