SERVER-67098 Add a server parameter to disable plan caching

3 files changed, 15 insertions, 1 deletions

diff --git a/src/mongo/db/query/canonical_query.cpp b/src/mongo/db/query/canonical_query.cpp
index 6449c5241fc..f340b4811d7 100644
--- a/src/mongo/db/query/canonical_query.cpp
+++ b/src/mongo/db/query/canonical_query.cpp
@@ -199,7 +199,10 @@ Status CanonicalQuery::init(OperationContext* opCtx,
     }
     auto unavailableMetadata = validStatus.getValue();
     _root = MatchExpression::normalize(std::move(root));
-    if (feature_flags::gFeatureFlagSbePlanCache.isEnabledAndIgnoreFCV()) {
+
+    // If caching is disabled, do not perform any autoparameterization.
+    if (!internalQueryDisablePlanCache.load() &&
+        feature_flags::gFeatureFlagSbePlanCache.isEnabledAndIgnoreFCV()) {
         const bool hasNoTextNodes =
             !QueryPlannerCommon::hasNode(_root.get(), MatchExpression::TEXT);
         if (hasNoTextNodes) {
diff --git a/src/mongo/db/query/classic_plan_cache.cpp b/src/mongo/db/query/classic_plan_cache.cpp
index 5f33481fef6..683b4b3660a 100644
--- a/src/mongo/db/query/classic_plan_cache.cpp
+++ b/src/mongo/db/query/classic_plan_cache.cpp
@@ -126,6 +126,10 @@ std::string SolutionCacheData::toString() const {
 }
 
 bool shouldCacheQuery(const CanonicalQuery& query) {
+    if (internalQueryDisablePlanCache.load()) {
+        return false;
+    }
+
     const FindCommandRequest& findCommand = query.getFindCommandRequest();
     const MatchExpression* expr = query.root();
 
diff --git a/src/mongo/db/query/query_knobs.idl b/src/mongo/db/query/query_knobs.idl
index 53c1e5e7617..9fa82639f51 100644
--- a/src/mongo/db/query/query_knobs.idl
+++ b/src/mongo/db/query/query_knobs.idl
@@ -129,6 +129,13 @@ server_parameters:
   # Plan cache
   #
 
+  internalQueryDisablePlanCache:
+    description:  "Disables caching of query plans for both classic and SBE engines."
+    set_at: [ startup ]
+    cpp_varname: "internalQueryDisablePlanCache"
+    cpp_vartype: AtomicWord<bool>
+    default: false
+
   internalQueryCacheMaxEntriesPerCollection:
     description: "The maximum number of entries allowed in a given collection's plan cache. Applies
     only to the classic plan cache, not to the SBE plan cache."