diff --git a/src/tests/perf_ptquery.cc b/src/tests/perf_ptquery.cc
index f88f7588400..dfd25d8e1c2 100644
--- a/src/tests/perf_ptquery.cc
+++ b/src/tests/perf_ptquery.cc
@@ -54,6 +54,7 @@ stress_table(DB_ENV* env, DB** dbp, struct cli_args *cli_args) {
     for (int i = 0; i < num_threads; i++) {
         arg_init(&myargs[i], dbp, env, cli_args);
         myargs[i].operation = ptquery_op;
+        myargs[i].txn_flags |= DB_TXN_READ_ONLY;
     }
     run_workers(myargs, num_threads, cli_args->num_seconds, false, cli_args);
 }
diff --git a/src/tests/perf_ptquery2.cc b/src/tests/perf_ptquery2.cc
index 116ae435746..66af246a837 100644
--- a/src/tests/perf_ptquery2.cc
+++ b/src/tests/perf_ptquery2.cc
@@ -67,6 +67,7 @@ stress_table(DB_ENV* env, DB** dbp, struct cli_args *cli_args) {
         thread_ids[i] = i % cli_args->num_DBs;
         myargs[i].operation = ptquery_op2;
         myargs[i].operation_extra = &thread_ids[i];
+        myargs[i].txn_flags |= DB_TXN_READ_ONLY;
     }
     run_workers(myargs, num_threads, cli_args->num_seconds, false, cli_args);
 }