diff --git a/test/jitter.cc b/test/jitter.cc
index c0f31a64..c7b8bccb 100644
--- a/test/jitter.cc
+++ b/test/jitter.cc
@@ -15,22 +15,15 @@
 #include "test.h"
 
 bool testcase_jitter::run() {
+  int err;
+  size_t upper_limit = config.params.size_upper;
+  if (upper_limit < 1)
+    upper_limit = config.params.size_now * 2;
+
   while (should_continue()) {
     jitter_delay();
     db_open();
 
-    if (flipcoin()) {
-      jitter_delay();
-      txn_begin(true);
-      fetch_canary();
-      jitter_delay();
-      txn_end(flipcoin());
-    }
-
-    int err;
-    intptr_t upper_limit = config.params.size_upper;
-    if (upper_limit < 1)
-      upper_limit = config.params.size_now;
     if (upper_limit < 1) {
       MDBX_envinfo info;
       err = mdbx_env_info_ex(db_guard.get(), txn_guard.get(), &info,
@@ -42,30 +35,33 @@ bool testcase_jitter::run() {
                         : INTPTR_MAX;
     }
 
-    const bool xcoin = flipcoin();
-    err = mdbx_env_set_geometry(db_guard.get(), -1, -1,
-                                xcoin ? upper_limit / 2 : upper_limit * 3 / 2,
-                                -1, -1, -1);
-    if (err != MDBX_SUCCESS && err != MDBX_RESULT_TRUE &&
-        err != MDBX_MAP_FULL && err != MDBX_TOO_LARGE)
-      failure_perror("mdbx_env_set_geometry-1", err);
+    if (flipcoin()) {
+      jitter_delay();
+      txn_begin(true);
+      fetch_canary();
+      jitter_delay();
+      txn_end(flipcoin());
+    }
 
+    const bool coin4size = flipcoin();
     jitter_delay();
     txn_begin(mode_readonly());
     jitter_delay();
     if (!mode_readonly()) {
       fetch_canary();
       update_canary(1);
-      /* TODO:
-       *  - db_setsize()
-       *  ...
-       */
+      err = mdbx_env_set_geometry(
+          db_guard.get(), -1, -1,
+          coin4size ? upper_limit * 2 / 3 : upper_limit * 3 / 2, -1, -1, -1);
+      if (err != MDBX_SUCCESS && err != MDBX_RESULT_TRUE &&
+          err != MDBX_MAP_FULL && err != MDBX_TOO_LARGE)
+        failure_perror("mdbx_env_set_geometry-1", err);
     }
     txn_end(flipcoin());
 
-    err = mdbx_env_set_geometry(db_guard.get(), -1, -1,
-                                !xcoin ? upper_limit / 2 : upper_limit * 3 / 2,
-                                -1, -1, -1);
+    err = mdbx_env_set_geometry(
+        db_guard.get(), -1, -1,
+        !coin4size ? upper_limit * 2 / 3 : upper_limit * 3 / 2, -1, -1, -1);
     if (err != MDBX_SUCCESS && err != MDBX_RESULT_TRUE &&
         err != MDBX_MAP_FULL && err != MDBX_TOO_LARGE)
       failure_perror("mdbx_env_set_geometry-2", err);