fix posting align with series

Signed-off-by: Ben Ye <[email protected]>

pkg/store/bucket.go

@@ -2606,7 +2606,7 @@ func (r *bucketIndexReader) ExpandedPostings(
 		return nil, nil
 	}
 
-	hit, postings, err := r.fetchSingleExpandedPostingFromCacheAndExpand(ctx, ms, bytesLimiter, tenant)
+	hit, postings, err := r.fetchAlignedExpandedPostingFromCacheAndExpand(ctx, ms, bytesLimiter, tenant)
 	if err != nil {
 		return nil, err
 	}
@@ -2956,8 +2956,8 @@ type postingPtr struct {
 	ptr   index.Range
 }
 
-func (r *bucketIndexReader) fetchSingleExpandedPostingFromCacheAndExpand(ctx context.Context, ms []*labels.Matcher, bytesLimiter BytesLimiter, tenant string) (bool, []storage.SeriesRef, error) {
-	postings, closers, err := r.fetchExpandedPostingsFromCache(ctx, [][]*labels.Matcher{ms}, bytesLimiter, tenant)
+func (r *bucketIndexReader) fetchAlignedExpandedPostingFromCacheAndExpand(ctx context.Context, ms []*labels.Matcher, bytesLimiter BytesLimiter, tenant string) (bool, []storage.SeriesRef, error) {
+	postings, closers, err := r.fetchExpandedPostingsFromCache(ctx, [][]*labels.Matcher{ms}, bytesLimiter, tenant, true)
 	defer func() {
 		for _, closer := range closers {
 			closer()
@@ -2980,7 +2980,7 @@ func (r *bucketIndexReader) fetchSingleExpandedPostingFromCacheAndExpand(ctx con
 	return true, ps, nil
 }
 
-func (r *bucketIndexReader) fetchExpandedPostingsFromCache(ctx context.Context, ms [][]*labels.Matcher, bytesLimiter BytesLimiter, tenant string) ([]index.Postings, []func(), error) {
+func (r *bucketIndexReader) fetchExpandedPostingsFromCache(ctx context.Context, ms [][]*labels.Matcher, bytesLimiter BytesLimiter, tenant string, seriesByteAligned bool) ([]index.Postings, []func(), error) {
 	if len(ms) == 0 {
 		return nil, nil, nil
 	}
@@ -3013,17 +3013,19 @@ func (r *bucketIndexReader) fetchExpandedPostingsFromCache(ctx context.Context,
 				continue
 			}
 
-			// As of version two all series entries are 16 byte padded. All references
-			// we get have to account for that to get the correct offset.
-			version, err := r.IndexVersion()
-			if err != nil {
-				return nil, closeFns, errors.Wrap(err, "get index version")
-			}
-
 			res[i] = p
-			if version >= 2 {
-				// Index version 2 series are padded by 16 bytes.
-				res[i] = newSeriesByteAlignedPostings(p)
+			if seriesByteAligned {
+				// As of version two all series entries are 16 byte padded. All references
+				// we get have to account for that to get the correct offset.
+				version, err := r.IndexVersion()
+				if err != nil {
+					return nil, closeFns, errors.Wrap(err, "get index version")
+				}
+
+				if version >= 2 {
+					// Index version 2 series are padded by 16 bytes.
+					res[i] = newSeriesByteAlignedPostings(p)
+				}
 			}
 		}
 	}
@@ -3082,7 +3084,7 @@ func (r *bucketIndexReader) fetchPostings(ctx context.Context, postingGroups []*
 	timer := prometheus.NewTimer(r.block.metrics.postingsFetchDuration.WithLabelValues(tenant))
 	defer timer.ObserveDuration()
 
-	expandedPostings, closers, err := r.fetchExpandedPostingsFromCache(ctx, expandedPostingMatchers, bytesLimiter, tenant)
+	expandedPostings, closers, err := r.fetchExpandedPostingsFromCache(ctx, expandedPostingMatchers, bytesLimiter, tenant, false)
 	closeFns = append(closeFns, closers...)
 	if err != nil {
 		return nil, closeFns, errors.Wrap(err, "fetch expanded postings from cache")