.

zrace.py → zopenrace.py

@@ -54,10 +54,32 @@ Below is timing diagram on how the bug happens on ZODB5:
 
 The program simulates two clients: one (T2) constantly modifies two integer
 objects preserving invariant that their values stay equal. The other client
-(T1) constatly opens the database and verifies the invariant. T1 forces access
+(T1) constantly opens the database and verifies the invariant. T1 forces access
 to one of the object to always go through loading from the database, and this
 way if live cache becomes stale the bug is observed as invariant breakage.
 
+Here is example failure:
+
+    $ taskset -c 1,2 ./zopenrace.py
+    Exception in thread Thread-1:
+    Traceback (most recent call last):
+      File "/usr/lib/python2.7/threading.py", line 801, in __bootstrap_inner
+        self.run()
+      File "/usr/lib/python2.7/threading.py", line 754, in run
+        self.__target(*self.__args, **self.__kwargs)
+      File "./zopenrace.py", line 136, in T1
+        t1()
+      File "./zopenrace.py", line 130, in t1
+        raise AssertionError("t1: obj1.i (%d)  !=  obj2.i (%d)" % (i1, i2))
+    AssertionError: t1: obj1.i (147)  !=  obj2.i (146)
+
+    Traceback (most recent call last):
+      File "./zopenrace.py", line 179, in <module>
+        main()
+      File "./zopenrace.py", line 174, in main
+        raise AssertionError('FAIL')
+    AssertionError: FAIL
+
 XXX ZODB4 and ZODB3
 
 [1] https://github.com/zopefoundation/ZODB/blob/5.5.1-29-g0b3db5aee/src/ZODB/Connection.py#L734-L742