Hey Gijs, I'm seeing a difference in how MonetDB and SQLite handle transactions inside Django. Here's my current unit test in Django (it passes w/ SQLite and fails with MonetDB): 1 : s1 = Simple(name="mark") 2 : s1.save() 3 : 4 : s2 = Simple(name="mark") 5 : try: 6 : s2.save() 7 : except IntegrityError: 8 : pass 9 : 10 : s = Simple.objects.get(name="mark") 11 : print s What happens under SQLite is the save on line 6 fails, but the select on line 10 works. In MonetDB, at line 10, I get the error current transaction is aborted (please ROLLBACK) Here's the trace of mapi2 commands, starting from line 2 mapi2.py, cmd, operation = sINSERT INTO "testapp_simple" ("name") VALUES ('mark'); mapi2.py, cmd, operation = Xreply_size 1 mapi2.py, cmd, operation = sCOMMIT; mapi2.py, cmd, operation = Xreply_size 1000 mapi2.py, cmd, operation = sINSERT INTO "testapp_simple" ("name") VALUES ('mark'); mapi2.py, cmd, operation = Xreply_size 1000 mapi2.py, cmd, operation = sSELECT "testapp_simple"."id", "testapp_simple"."name" FROM "testapp_simple" WHERE "testapp_simple"."name" = 'mark' ; mapi2.py, cmd, operation = Xreply_size 1 mapi2.py, cmd, operation = sROLLBACK; It looks like the ROLLBACK isn't executed until the connection closes. With auto commit off, shouldn't the ROLLBACK fire as soon as the insert fails? If so, how do I fix this? Thanks m