1 files changed, 2 insertions, 1 deletions
diff --git a/src/mongo/db/pipeline/document_source_plan_cache_stats.h b/src/mongo/db/pipeline/document_source_plan_cache_stats.h
index f091a24f1b3..d706f4f3ba4 100644
--- a/src/mongo/db/pipeline/document_source_plan_cache_stats.h
+++ b/src/mongo/db/pipeline/document_source_plan_cache_stats.h
@@ -91,7 +91,8 @@ public:
                                      DiskUseRequirement::kNoDiskUse,
                                      FacetRequirement::kNotAllowed,
                                      TransactionRequirement::kNotAllowed,
-                                     LookupRequirement::kAllowed};
+                                     LookupRequirement::kAllowed,
+                                     UnionRequirement::kAllowed};
 
         constraints.requiresInputDocSource = false;
         return constraints;