SERVER-35891 add failpoints to disable aggregation optimizations

1 files changed, 13 insertions, 0 deletions

diff --git a/src/mongo/db/matcher/expression.h b/src/mongo/db/matcher/expression.h
index bc86ec7852c..bc0796dc1a7 100644
--- a/src/mongo/db/matcher/expression.h
+++ b/src/mongo/db/matcher/expression.h
@@ -40,9 +40,16 @@
 #include "mongo/db/pipeline/dependencies.h"
 #include "mongo/stdx/functional.h"
 #include "mongo/stdx/memory.h"
+#include "mongo/util/fail_point_service.h"
 
 namespace mongo {
 
+/**
+ * Enabling the disableMatchExpressionOptimization fail point will stop match expressions from
+ * being optimized.
+ */
+MONGO_FAIL_POINT_DECLARE(disableMatchExpressionOptimization);
+
 class CollatorInterface;
 class MatchExpression;
 class TreeMatchExpression;
@@ -135,6 +142,12 @@ public:
      * The value of 'expression' must not be nullptr.
      */
     static std::unique_ptr<MatchExpression> optimize(std::unique_ptr<MatchExpression> expression) {
+        // If the disableMatchExpressionOptimization failpoint is enabled, optimizations are skipped
+        // and the expression is left unmodified.
+        if (MONGO_FAIL_POINT(disableMatchExpressionOptimization)) {
+            return expression;
+        }
+
         auto optimizer = expression->getOptimizer();
         return optimizer(std::move(expression));
     }