diff --git a/index/scorch/merge.go b/index/scorch/merge.go
index 005d4f41..ee3ec46c 100644
--- a/index/scorch/merge.go
+++ b/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
diff --git a/index/scorch/scorch.go b/index/scorch/scorch.go
index 87372a32..a40f374a 100644
--- a/index/scorch/scorch.go
+++ b/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
diff --git a/index/scorch/segment/mem/build.go b/index/scorch/segment/mem/build.go
index 643ae36e..57971aae 100644
--- a/index/scorch/segment/mem/build.go
+++ b/index/scorch/segment/mem/build.go
@@ -253,7 +253,7 @@ func (s *Segment) processDocument(result *index.AnalysisResult) {
 	// now that its been rolled up into docMap, walk that
 	for fieldID, tokenFrequencies := range docMap {
 		dict := s.Dicts[fieldID]
-		norm := float32(1.0/math.Sqrt(float64(fieldLens[fieldID])))
+		norm := float32(1.0 / math.Sqrt(float64(fieldLens[fieldID])))
 		for term, tokenFreq := range tokenFrequencies {
 			pid := dict[term] - 1
 			bs := s.Postings[pid]
diff --git a/index/scorch/segment/mem/dict.go b/index/scorch/segment/mem/dict.go
index cf92ef71..b564ed1f 100644
--- a/index/scorch/segment/mem/dict.go
+++ b/index/scorch/segment/mem/dict.go
@@ -33,12 +33,20 @@ type Dictionary struct {
 // PostingsList returns the postings list for the specified term
 func (d *Dictionary) PostingsList(term string,
 	except *roaring.Bitmap) (segment.PostingsList, error) {
-	return &PostingsList{
-		dictionary: d,
-		term:       term,
-		postingsID: d.segment.Dicts[d.fieldID][term],
-		except:     except,
-	}, nil
+	return d.InitPostingsList(term, except, nil)
+}
+
+func (d *Dictionary) InitPostingsList(term string, except *roaring.Bitmap,
+	prealloc *PostingsList) (*PostingsList, error) {
+	rv := prealloc
+	if rv == nil {
+		rv = &PostingsList{}
+	}
+	rv.dictionary = d
+	rv.term = term
+	rv.postingsID = d.segment.Dicts[d.fieldID][term]
+	rv.except = except
+	return rv, nil
 }
 
 // Iterator returns an iterator for this dictionary
diff --git a/index/scorch/segment/mem/posting.go b/index/scorch/segment/mem/posting.go
index 25cbeb45..2554333a 100644
--- a/index/scorch/segment/mem/posting.go
+++ b/index/scorch/segment/mem/posting.go
@@ -46,9 +46,16 @@ func (p *PostingsList) Count() uint64 {
 
 // Iterator returns an iterator for this postings list
 func (p *PostingsList) Iterator() segment.PostingsIterator {
-	rv := &PostingsIterator{
-		postings: p,
+	return p.InitIterator(nil)
+}
+func (p *PostingsList) InitIterator(prealloc *PostingsIterator) *PostingsIterator {
+	rv := prealloc
+	if rv == nil {
+		rv = &PostingsIterator{postings: p}
+	} else {
+		*rv = PostingsIterator{postings: p}
 	}
+
 	if p.postingsID > 0 {
 		allbits := p.dictionary.segment.Postings[p.postingsID-1]
 		rv.locations = p.dictionary.segment.PostingsLocs[p.postingsID-1]
diff --git a/index/scorch/segment/zap/build.go b/index/scorch/segment/zap/build.go
index b075496c..237cc5f3 100644
--- a/index/scorch/segment/zap/build.go
+++ b/index/scorch/segment/zap/build.go
@@ -308,7 +308,7 @@ func persistStoredFieldValues(fieldID int,
 }
 
 func persistPostingDetails(memSegment *mem.Segment, w *CountHashWriter, chunkFactor uint32) ([]uint64, []uint64, error) {
-	var freqOffsets, locOfffsets []uint64
+	freqOffsets := make([]uint64, 0, len(memSegment.Postings))
 	tfEncoder := newChunkedIntCoder(uint64(chunkFactor), uint64(len(memSegment.Stored)-1))
 	for postingID := range memSegment.Postings {
 		if postingID != 0 {
@@ -351,6 +351,7 @@ func persistPostingDetails(memSegment *mem.Segment, w *CountHashWriter, chunkFac
 	}
 
 	// now do it again for the locations
+	locOffsets := make([]uint64, 0, len(memSegment.Postings))
 	locEncoder := newChunkedIntCoder(uint64(chunkFactor), uint64(len(memSegment.Stored)-1))
 	for postingID := range memSegment.Postings {
 		if postingID != 0 {
@@ -367,7 +368,8 @@ func persistPostingDetails(memSegment *mem.Segment, w *CountHashWriter, chunkFac
 		var locOffset int
 		for postingsListItr.HasNext() {
 			docNum := uint64(postingsListItr.Next())
-			for i := 0; i < int(freqs[offset]); i++ {
+			n := int(freqs[offset])
+			for i := 0; i < n; i++ {
 				if len(locfields) > 0 {
 					// put field
 					err := locEncoder.Add(docNum, uint64(locfields[locOffset]))
@@ -414,14 +416,15 @@ func persistPostingDetails(memSegment *mem.Segment, w *CountHashWriter, chunkFac
 		}
 
 		// record where this postings loc info starts
-		locOfffsets = append(locOfffsets, uint64(w.Count()))
+		locOffsets = append(locOffsets, uint64(w.Count()))
 		locEncoder.Close()
 		_, err := locEncoder.Write(w)
 		if err != nil {
 			return nil, nil, err
 		}
 	}
-	return freqOffsets, locOfffsets, nil
+
+	return freqOffsets, locOffsets, nil
 }
 
 func persistPostingsLocs(memSegment *mem.Segment, w *CountHashWriter) (rv []uint64, err error) {
@@ -532,6 +535,9 @@ func persistDocValues(memSegment *mem.Segment, w *CountHashWriter,
 	fieldChunkOffsets := make(map[uint16]uint64, len(memSegment.FieldsInv))
 	fdvEncoder := newChunkedContentCoder(uint64(chunkFactor), uint64(len(memSegment.Stored)-1))
 
+	var postings *mem.PostingsList
+	var postingsItr *mem.PostingsIterator
+
 	for fieldID := range memSegment.DocValueFields {
 		field := memSegment.FieldsInv[fieldID]
 		docTermMap := make(map[uint64][]byte, 0)
@@ -543,12 +549,13 @@ func persistDocValues(memSegment *mem.Segment, w *CountHashWriter,
 		dictItr := dict.Iterator()
 		next, err := dictItr.Next()
 		for err == nil && next != nil {
-			postings, err1 := dict.PostingsList(next.Term, nil)
+			var err1 error
+			postings, err1 = dict.(*mem.Dictionary).InitPostingsList(next.Term, nil, postings)
 			if err1 != nil {
 				return nil, err
 			}
 
-			postingsItr := postings.Iterator()
+			postingsItr = postings.InitIterator(postingsItr)
 			nextPosting, err2 := postingsItr.Next()
 			for err2 == nil && nextPosting != nil {
 				docNum := nextPosting.Number()
@@ -566,7 +573,7 @@ func persistDocValues(memSegment *mem.Segment, w *CountHashWriter,
 		}
 
 		// sort wrt to docIDs
-		var docNumbers docIDRange
+		docNumbers := make(docIDRange, 0, len(docTermMap))
 		for k := range docTermMap {
 			docNumbers = append(docNumbers, k)
 		}
diff --git a/index/scorch/stats.go b/index/scorch/stats.go
index cd416a7c..3c978af7 100644
--- a/index/scorch/stats.go
+++ b/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
 }