Re: Postgresql 7.1.3 not thread safe

Alain Picard <Alain(dot)Picard(at)memetrics(dot)com> writes:
> Behold!

> select * from test_table
> where data !='bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb'
> and
> data != 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa';

> -> returns:

> id | data
> --------+------------------------------------------------------------------
> 253084 | bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
> 55068 | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
> (2 rows)

I would say that you have either faulty RAM or a faulty disk drive.
Given the apparent dependence on running more than one backend at a
time, faulty RAM is perhaps more likely (the bad chip could be in
RAM locations that don't get used unless lots of processes are running).
The apparent single-bit nature of the fault also points to a bad RAM
location; disks tend to drop multiple words or whole sectors, not
single bits. But dropped bits during I/O transfers shouldn't be ruled
out completely.

Have you run any hardware diagnostics lately?

regards, tom lane