> My other pet peeve is the default max connections setting. This should be
> higher if possible, but of course, there's always the possibility of
> running out of file descriptors.
>
> Apache has a default max children of 150, and if using PHP or another
> language that runs as an apache module, it is quite possible to use up all
> the pgsql backend slots before using up all the apache child slots.
>
> Is setting the max connections to something like 200 reasonable, or likely
> to cause too many problems?
It likely. First you will ran out kernel file descriptors. This could
be solved by increasing the kernel table or lowering
max_files_per_process, though. Second the total throughput will
rapidly descrease if you don't have enough RAM and many
CPUs. PostgreSQL can not handle many concurrent
connections/transactions effectively. I recommend to employ some kind
of connection pooling software and lower the max connections.
--
Tatsuo Ishii