Un-revert #6451 (#6780)

* Revert "Revert "Check for errors when iterating through chunks or samples in response to a query (#6451)" (#6576)"

This reverts commit ad50cda.

* Update CHANGELOG.md

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 * [CHANGE] Ingester: Increase default value of `-blocks-storage.tsdb.head-postings-for-matchers-cache-max-bytes` and `-blocks-storage.tsdb.block-postings-for-matchers-cache-max-bytes` to 100 MiB (previous default value was 10 MiB). #6764
 * [ENHANCEMENT] PromQL: ignore small errors for bucketQuantile #6766
+* [BUGFIX] Ingester: don't ignore errors encountered while iterating through chunks or samples in response to a query request. #6451
 * [BUGFIX] Fix issue where queries can fail or omit OOO samples if OOO head compaction occurs between creating a querier and reading chunks #6766
 * [BUGFIX] Fix issue where concatenatingChunkIterator can obscure errors #6766
 * [BUGFIX] Fix panic during tsdb Commit #6766

pkg/ingester/ingester.go

@@ -1799,6 +1799,11 @@ func (i *Ingester) executeSamplesQuery(ctx context.Context, db *userTSDB, from,
 				return 0, 0, fmt.Errorf("unsupported value type: %v", valType)
 			}
 		}
+
+		if err := it.Err(); err != nil {
+			return 0, 0, err
+		}
+
 		numSamples += len(ts.Samples) + len(ts.Histograms)
 		numSeries++
 		tsSize := ts.Size()
@@ -1895,6 +1900,11 @@ func (i *Ingester) executeChunksQuery(ctx context.Context, db *userTSDB, from, t
 			ts.Chunks = append(ts.Chunks, ch)
 			numSamples += meta.Chunk.NumSamples()
 		}
+
+		if err := it.Err(); err != nil {
+			return 0, 0, err
+		}
+
 		numSeries++
 		tsSize := ts.Size()
 
@@ -2114,6 +2124,10 @@ func (i *Ingester) sendStreamingQueryChunks(allSeries *chunkSeriesNode, stream c
 				numSamples += meta.Chunk.NumSamples()
 			}
 
+			if err := it.Err(); err != nil {
+				return 0, 0, 0, err
+			}
+
 			numChunks += len(seriesChunks.Chunks)
 			msgSize := seriesChunks.Size()