Tom Lane wrote: > Alvaro Herrera <alvhe...@commandprompt.com> writes:
> > But freed memory is clobbered, so if we were to have an assert that > > checks the node tag, it should show up. In fact, we do have such an > > assert, but only for compilers other than GCC, because the inline > > version of palloc() cannot have it for lack of infrastructure. > > Well, but production installations don't have either memory clobbering > or Asserts, so fooling with that wouldn't have helped anyway. I suspect > what really happened here is that the bug was created by some late > change during 8.1 development, and nobody ever exercised the > anti-wraparound code path after that in an assert-enabled build :-( > In a non-assert build there's a fairly good chance that it'd still > work because the context header would still be there undamaged. Well, my builds are all assert-enabled, and I still wasn't able to make it crash in any way (the new context being allocated in the same position as the old one is the only explanation I have, but I did not investigate whether that's what happening). Maybe Greg Stark's idea of offsetting pointers returned by palloc could have helped to find the problem from the outset. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
