From a7bedd16750176df8856ae22bc8e4bb1b89a466c Mon Sep 17 00:00:00 2001
From: Ben Ye <benye@amazon.com>
Date: Thu, 21 Mar 2024 09:47:51 +0000
Subject: [PATCH] fix lazy expanded postings cache and bug of non equal matcher
 with non existent values

Signed-off-by: Ben Ye <benye@amazon.com>
---
 pkg/store/bucket.go        | 10 ++++++----
 pkg/store/lazy_postings.go |  9 +++++++--
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/pkg/store/bucket.go b/pkg/store/bucket.go
index 20cf10e657d..4d5529c8ce7 100644
--- a/pkg/store/bucket.go
+++ b/pkg/store/bucket.go
@@ -1196,13 +1196,10 @@ OUTER:
 		if err := b.ctx.Err(); err != nil {
 			return err
 		}
-		ok, err := b.indexr.LoadSeriesForTime(postingsBatch[i], &b.symbolizedLset, &b.chkMetas, b.skipChunks, b.mint, b.maxt)
+		hasMatchedChunks, err := b.indexr.LoadSeriesForTime(postingsBatch[i], &b.symbolizedLset, &b.chkMetas, b.skipChunks, b.mint, b.maxt)
 		if err != nil {
 			return errors.Wrap(err, "read series")
 		}
-		if !ok {
-			continue
-		}
 
 		if err := b.indexr.LookupLabelsSymbols(b.ctx, b.symbolizedLset, b.b); err != nil {
 			return errors.Wrap(err, "Lookup labels symbols")
@@ -1221,6 +1218,11 @@ OUTER:
 		if b.lazyPostings.lazyExpanded() {
 			b.expandedPostings = append(b.expandedPostings, postingsBatch[i])
 		}
+		// Even though there is no chunks found in the requested time range, we need to continue
+		// for loop after checking lazy posting matchers because of the expanded postings cache.
+		if !hasMatchedChunks {
+			continue
+		}
 
 		completeLabelset := labelpb.ExtendSortedLabels(b.lset, b.extLset)
 		if b.extLsetToRemove != nil {
diff --git a/pkg/store/lazy_postings.go b/pkg/store/lazy_postings.go
index cb245180cf2..0f4038bc61d 100644
--- a/pkg/store/lazy_postings.go
+++ b/pkg/store/lazy_postings.go
@@ -54,10 +54,15 @@ func optimizePostingsFetchByDownloadedBytes(r *bucketIndexReader, postingGroups
 			return nil, false, errors.Wrapf(err, "postings offsets for %s", pg.name)
 		}
 
-		// No posting ranges found means empty posting.
-		if len(rngs) == 0 {
+		// If the posting group adds keys, no posting ranges found means empty posting.
+		if len(pg.addKeys) > 0 && len(rngs) == 0 {
 			return nil, true, nil
 		}
+		// If the posting group removes keys, no posting ranges found is fine. It means
+		// that the posting group is a noop. {job != "some_non_existent_value"}
+		if len(pg.removeKeys) > 0 && len(rngs) == 0 {
+			continue
+		}
 		for _, r := range rngs {
 			if r == indexheader.NotFoundRange {
 				continue