Hi. This message is going to xen-devel (because that's where the osstest project is) and to pgsql-hackers (because I hope they may be able to advise about the scope of the PostgreSQL SERIALIZABLE constraint problem).
In summary: PostgreSQL only provides transaction serialisability for successful transactions. Even with SERIALIZABLE, transactions may fail due to spurious and "impossible" constraint violations. As a result, I need to make osstest retry transactions not only on explicitly reported serialisation failures and deadlocks, but also on integrity violations. It is not clear to me from the thread WIP: Detecting SSI conflicts before reporting constraint violations which was on pgsql-hackers earlier this year, whether it is only unique constraint violations which may spuriously occur. Can anyone from the PostgreSQL hacker community advise ? The existing documentation patch just talks about "successful" transactions, and uses unique constraints as an example. In principle this leaves open the possibility that the transaction might fail with bizarre and unpredictable error codes, although I hope this isn't possible. It would be good to narrow the scope of the retries in my system as much as possible. I'm hoping to get an authoritative answer here but it seems that this is a common problem to which there is still not yet a definitive solution. I would like there to be a definitive solution. If I get a clear answer I'll submit a further docs patch to pgsql :-). Thanks, Ian. -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers