diff --git a/src/engine/Server.cpp b/src/engine/Server.cpp
index 346977351f..4d37a719ba 100644
--- a/src/engine/Server.cpp
+++ b/src/engine/Server.cpp
@@ -632,7 +632,7 @@ Awaitable<Server::PlannedQuery> Server::planQuery(
 // _____________________________________________________________________________
 json Server::composeErrorResponseJson(
     const string& query, const std::string& errorMsg,
-    ad_utility::Timer& requestTimer,
+    const ad_utility::Timer& requestTimer,
     const std::optional<ExceptionMetadata>& metadata) {
   json j;
   using ad_utility::Timer;
@@ -712,7 +712,7 @@ ad_utility::websocket::OwningQueryId Server::getQueryId(
 Awaitable<void> Server::sendStreamableResponse(
     const ad_utility::httpUtils::HttpRequest auto& request, auto& send,
     MediaType mediaType, const PlannedQuery& plannedQuery,
-    const QueryExecutionTree& qet, ad_utility::Timer& requestTimer,
+    const QueryExecutionTree& qet, const ad_utility::Timer& requestTimer,
     SharedCancellationHandle cancellationHandle) const {
   auto responseGenerator = ExportQueryExecutionTrees::computeResult(
       plannedQuery.parsedQuery_, qet, mediaType, requestTimer,
@@ -802,7 +802,7 @@ ad_utility::websocket::MessageSender Server::createMessageSender(
 // ____________________________________________________________________________
 Awaitable<void> Server::processQuery(
     const ad_utility::url_parser::ParamValueMap& params, ParsedQuery&& query,
-    ad_utility::Timer& requestTimer,
+    const ad_utility::Timer& requestTimer,
     ad_utility::SharedCancellationHandle cancellationHandle,
     QueryExecutionContext& qec,
     const ad_utility::httpUtils::HttpRequest auto& request, auto&& send,
@@ -948,7 +948,7 @@ json Server::processUpdateImpl(
 
 // ____________________________________________________________________________
 Awaitable<void> Server::processUpdate(
-    ParsedQuery&& update, ad_utility::Timer& requestTimer,
+    ParsedQuery&& update, const ad_utility::Timer& requestTimer,
     ad_utility::SharedCancellationHandle cancellationHandle,
     QueryExecutionContext& qec,
     const ad_utility::httpUtils::HttpRequest auto& request, auto&& send,
@@ -985,7 +985,7 @@ template <QL_CONCEPT_OR_TYPENAME(QueryOrUpdate) Operation>
 Awaitable<void> Server::processQueryOrUpdate(
     const ad_utility::url_parser::ParamValueMap& params,
     ParsedQuery&& parsedOperation, SharedCancellationHandle cancellationHandle,
-    QueryExecutionContext qec, ad_utility::Timer& requestTimer,
+    QueryExecutionContext qec, const ad_utility::Timer& requestTimer,
     const ad_utility::httpUtils::HttpRequest auto& request, auto&& send,
     TimeLimit timeLimit) {
   using namespace ad_utility::httpUtils;
diff --git a/src/engine/Server.h b/src/engine/Server.h
index 177c9ef54d..1088aa4189 100644
--- a/src/engine/Server.h
+++ b/src/engine/Server.h
@@ -143,13 +143,13 @@ class Server {
       const ad_utility::url_parser::ParamValueMap& params,
       ParsedQuery&& parsedOperation,
       SharedCancellationHandle cancellationHandle, QueryExecutionContext qec,
-      ad_utility::Timer& requestTimer,
+      const ad_utility::Timer& requestTimer,
       const ad_utility::httpUtils::HttpRequest auto& request, auto&& send,
       TimeLimit timeLimit);
   // Do the actual execution of a query.
   Awaitable<void> processQuery(
       const ad_utility::url_parser::ParamValueMap& params, ParsedQuery&& query,
-      ad_utility::Timer& requestTimer,
+      const ad_utility::Timer& requestTimer,
       ad_utility::SharedCancellationHandle cancellationHandle,
       QueryExecutionContext& qec,
       const ad_utility::httpUtils::HttpRequest auto& request, auto&& send,
@@ -165,7 +165,7 @@ class Server {
   FRIEND_TEST(ServerTest, createResponseMetadata);
   // Do the actual execution of an update.
   Awaitable<void> processUpdate(
-      ParsedQuery&& update, ad_utility::Timer& requestTimer,
+      ParsedQuery&& update, const ad_utility::Timer& requestTimer,
       ad_utility::SharedCancellationHandle cancellationHandle,
       QueryExecutionContext& qec,
       const ad_utility::httpUtils::HttpRequest auto& request, auto&& send,
@@ -209,7 +209,7 @@ class Server {
 
   static json composeErrorResponseJson(
       const string& query, const std::string& errorMsg,
-      ad_utility::Timer& requestTimer,
+      const ad_utility::Timer& requestTimer,
       const std::optional<ExceptionMetadata>& metadata = std::nullopt);
 
   json composeStatsJson() const;
@@ -282,6 +282,6 @@ class Server {
   Awaitable<void> sendStreamableResponse(
       const ad_utility::httpUtils::HttpRequest auto& request, auto& send,
       ad_utility::MediaType mediaType, const PlannedQuery& plannedQuery,
-      const QueryExecutionTree& qet, ad_utility::Timer& requestTimer,
+      const QueryExecutionTree& qet, const ad_utility::Timer& requestTimer,
       SharedCancellationHandle cancellationHandle) const;
 };