Receiver: Handle storage exemplar multi-error

CHANGELOG.md

@@ -12,6 +12,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 - [#5453](https://github.com/thanos-io/thanos/pull/5453) Compact: Skip erroneous empty non `*AggrChunk` chunks during 1h downsampling of 5m resolution blocks.
 
 ### Fixed
+- [#5502](https://github.com/thanos-io/thanos/pull/5502) Receive: Handle exemplar storage errors as conflict error.
 
 ### Added
 

pkg/receive/handler.go

@@ -815,6 +815,9 @@ func isConflict(err error) bool {
 		err == storage.ErrDuplicateSampleForTimestamp ||
 		err == storage.ErrOutOfOrderSample ||
 		err == storage.ErrOutOfBounds ||
+		err == storage.ErrDuplicateExemplar ||
+		err == storage.ErrOutOfOrderExemplar ||
+		err == storage.ErrExemplarLabelLength ||
 		status.Code(err) == codes.AlreadyExists
 }
 

pkg/receive/handler_test.go

@@ -104,6 +104,16 @@ func TestDetermineWriteErrorCause(t *testing.T) {
 			threshold: 1,
 			exp:       errConflict,
 		},
+		{
+			name: "matching multierror (exemplar error)",
+			err: errutil.NonNilMultiError([]error{
+				storage.ErrExemplarLabelLength,
+				errors.New("foo"),
+				errors.New("bar"),
+			}),
+			threshold: 1,
+			exp:       errConflict,
+		},
 		{
 			name: "matching but below threshold multierror",
 			err: errutil.NonNilMultiError([]error{
@@ -139,6 +149,19 @@ func TestDetermineWriteErrorCause(t *testing.T) {
 			threshold: 2,
 			exp:       errNotReady,
 		},
+		{
+			name: "matching multierror many, one above threshold (exemplar error)",
+			err: errutil.NonNilMultiError([]error{
+				tsdb.ErrNotReady,
+				tsdb.ErrNotReady,
+				storage.ErrDuplicateExemplar,
+				storage.ErrDuplicateSampleForTimestamp,
+				storage.ErrExemplarLabelLength,
+				errors.New("foo"),
+			}),
+			threshold: 2,
+			exp:       errConflict,
+		},
 		{
 			name: "matching multierror many, both above threshold, conflict have precedence",
 			err: errutil.NonNilMultiError([]error{