addressing review comments

build.go

@@ -175,7 +175,7 @@ func InitSegmentBase(mem []byte, memCRC uint32, chunkMode uint32,
 		docValueOffset:      0, // docValueOffsets identified automatically by the section
 		dictLocs:            dictLocs,
 		fieldFSTs:           make(map[uint16]*vellum.FST),
-		vectorCache:         newVectorCache(),
+		vectorCache:         newVectorIndexCache(),
 	}
 	sb.updateSize()
 

faiss_vector_cache.go

@@ -25,7 +25,7 @@ import (
 	faiss "github.com/blevesearch/go-faiss"
 )
 
-type vecCache struct {
+type vecIndexCache struct {
 	closeCh chan struct{}
 	m       sync.RWMutex
 	cache   map[uint16]*cacheEntry
@@ -44,24 +44,23 @@ type cacheEntry struct {
 	index *faiss.IndexImpl
 }
 
-func newVectorCache() *vecCache {
-	return &vecCache{
+func newVectorIndexCache() *vecIndexCache {
+	return &vecIndexCache{
 		cache:   make(map[uint16]*cacheEntry),
 		closeCh: make(chan struct{}),
 	}
 }
 
-func (vc *vecCache) Clear() {
+func (vc *vecIndexCache) Clear() {
 	vc.m.Lock()
 	close(vc.closeCh)
 	vc.cache = nil
 	vc.m.Unlock()
-
 }
 
-func (vc *vecCache) checkCacheForVecIndex(fieldID uint16,
+func (vc *vecIndexCache) loadVectorIndex(fieldID uint16,
 	indexBytes []byte) (vecIndex *faiss.IndexImpl, err error) {
-	cachedIndex, present := vc.isVecIndexCached(fieldID)
+	cachedIndex, present := vc.isIndexCached(fieldID)
 	if present {
 		vecIndex = cachedIndex
 		vc.addRef(fieldID)
@@ -74,7 +73,7 @@ func (vc *vecCache) checkCacheForVecIndex(fieldID uint16,
 	return vecIndex, err
 }
 
-func (vc *vecCache) isVecIndexCached(fieldID uint16) (*faiss.IndexImpl, bool) {
+func (vc *vecIndexCache) isIndexCached(fieldID uint16) (*faiss.IndexImpl, bool) {
 	vc.m.RLock()
 	entry, present := vc.cache[fieldID]
 	vc.m.RUnlock()
@@ -89,30 +88,17 @@ func (vc *vecCache) isVecIndexCached(fieldID uint16) (*faiss.IndexImpl, bool) {
 	return rv, present && (rv != nil)
 }
 
-func (vc *vecCache) addRef(fieldIDPlus1 uint16) {
+func (vc *vecIndexCache) addRef(fieldIDPlus1 uint16) {
 	vc.m.RLock()
 	entry := vc.cache[fieldIDPlus1]
 	vc.m.RUnlock()
 
 	entry.addRef()
 }
 
-func (vc *vecCache) clearField(fieldIDPlus1 uint16) {
+func (vc *vecIndexCache) refresh() (rv int) {
 	vc.m.Lock()
-	delete(vc.cache, fieldIDPlus1)
-	vc.m.Unlock()
-}
-
-func (vc *vecCache) refreshEntries() (rv int) {
-	vc.m.RLock()
 	cache := vc.cache
-	vc.m.RUnlock()
-
-	defer func() {
-		vc.m.RLock()
-		rv = len(vc.cache)
-		vc.m.RUnlock()
-	}()
 
 	// for every field reconcile the average with the current sample values
 	for fieldIDPlus1, entry := range cache {
@@ -125,22 +111,25 @@ func (vc *vecCache) refreshEntries() (rv int) {
 		if entry.tracker.avg <= (1 - entry.tracker.alpha) {
 			atomic.StoreUint64(&entry.tracker.sample, 0)
 			entry.closeIndex()
-			vc.clearField(fieldIDPlus1)
+			delete(vc.cache, fieldIDPlus1)
 			continue
 		}
 		atomic.StoreUint64(&entry.tracker.sample, 0)
 	}
-	return
+
+	rv = len(vc.cache)
+	vc.m.Unlock()
+	return rv
 }
 
-func (vc *vecCache) monitor() {
+func (vc *vecIndexCache) monitor() {
 	ticker := time.NewTicker(1 * time.Second)
 	for {
 		select {
 		case <-vc.closeCh:
 			return
 		case <-ticker.C:
-			numEntries := vc.refreshEntries()
+			numEntries := vc.refresh()
 			if numEntries == 0 {
 				// no entries to be monitored, exit
 				return
@@ -149,7 +138,7 @@ func (vc *vecCache) monitor() {
 	}
 }
 
-func (vc *vecCache) update(fieldIDPlus1 uint16, index *faiss.IndexImpl) {
+func (vc *vecIndexCache) update(fieldIDPlus1 uint16, index *faiss.IndexImpl) {
 	vc.m.Lock()
 
 	// the first time we've hit the cache, try to spawn a monitoring routine

faiss_vector_cache_noop.go → faiss_vector_cache_nosup.go

@@ -17,11 +17,11 @@
 
 package zap
 
-type vecCache struct {
+type vecIndexCache struct {
 }
 
-func newVectorCache() *vecCache {
+func newVectorIndexCache() *vecIndexCache {
 	return nil
 }
 
-func (v *vecCache) Clear() {}
+func (v *vecIndexCache) Clear() {}

faiss_vector_posting.go

@@ -335,8 +335,8 @@ func (sb *SegmentBase) InterpretVectorIndex(field string, except *roaring.Bitmap
 				return rv, nil
 			},
 			close: func() {
-				// skipping the closing for now because the index is cached
-				// todo: subjected to change based on a optimization type flag
+				// skipping the closing because the index is cached and it's being
+				// deferred to a later point of time.
 			},
 			size: func() uint64 {
 				if vecIndex != nil {
@@ -394,9 +394,7 @@ func (sb *SegmentBase) InterpretVectorIndex(field string, except *roaring.Bitmap
 	indexSize, n := binary.Uvarint(sb.mem[pos : pos+binary.MaxVarintLen64])
 	pos += n
 
-	// todo: whether to cache the index or not can be determined by using the
-	// index optimization type flag.
-	vecIndex, err = sb.vectorCache.checkCacheForVecIndex(fieldIDPlus1, sb.mem[pos:pos+int(indexSize)])
+	vecIndex, err = sb.vectorCache.loadVectorIndex(fieldIDPlus1, sb.mem[pos:pos+int(indexSize)])
 	pos += int(indexSize)
 
 	return wrapVecIndex, err

segment.go

@@ -55,7 +55,7 @@ func (*ZapPlugin) Open(path string) (segment.Segment, error) {
 		SegmentBase: SegmentBase{
 			fieldsMap:      make(map[string]uint16),
 			fieldFSTs:      make(map[uint16]*vellum.FST),
-			vectorCache:    newVectorCache(),
+			vectorCache:    newVectorIndexCache(),
 			fieldDvReaders: make([]map[uint16]*docValueReader, len(segmentSections)),
 		},
 		f:    f,
@@ -113,7 +113,7 @@ type SegmentBase struct {
 
 	// fixme: although the operations and APIs of the vecCache is hidden under
 	// the vectors tag, the type should also perhaps be under the vectors tag.
-	vectorCache *vecCache
+	vectorCache *vecIndexCache
 }
 
 func (sb *SegmentBase) Size() int {