Re: [HACKERS] Postmaster options, process spawning, logging, etc.

1. Matthew's problem sounds an awful lot like what's being reported
by Lucio Andres Perez in v6.4.2. Maybe some kind of bug in detecting
and handling over-the-limit backends. Can someone cook up a Q&D backend-
spawner? I've spend enough time inside that part of the system lately that
I could probably track it down from a core file.

2. Yup, there's a "patch" out on pgsql-patches that previews an advanced log
system. Although the traditional elog method has seen a lot of enhancement
lately, it tends to be more geared towards development over administration.
Plus it was never designed to support national languages or machine parsing.

So far I've had not feedback on itm however, so I don't know if it will ever
make its way into a production release.

regards,

Tim Holloway

Tom Lane wrote:
>
> Matthew Hagerty <matthew(at)venux(dot)net> writes:
> > How many backend processes is considered a large number? The man pages
> > says the default is 32. Does anyone set their number higher?
>
> I've run test cases with 100, which is about as high as I can go on my
> personal box without running out of swap space. I think some people
> are using several hundred.
>
> > Kind of related to the question above; when does the postmaster spawn
> > another backend process? Is it for each additional connection,
>
> Per connection. The backend quits when the client disconnects. Of
> course, it's up to the client how long it stays connected or how many
> queries it asks...
>
> > The postmaster log file, why are the entries not datestamped?
>
> Uncomment #define ELOG_TIMESTAMPS in include/config.h after configure
> and before make...
>
> > Also, what is the highest debug level and how big can I expect
> > the log to grow? Can I rotate the log without stopping the postmaster?
>
> Not very readily. There is someone working on using syslog logging,
> which'd be a lot nicer than what we have.
>
> > What is the pg_log file in the data directory?
>
> Transaction commit data. Don't touch it ;-). It shouldn't be all that
> big, though...
>
> > What are the major system resources used by postgres, i.e. semaphores, file
> > handles, mbufs, etc.? I'm trying to determine if I have my resources
> > configured high enough for my user base.
>
> In 6.5, the postmaster won't start up if you don't have enough
> semaphores and shared memory. I've never heard of anyone running out of
> file handles, but it certainly seems possible if you start enough
> backends. Still, though, I wouldn't expect a hard coredump such as you
> are getting from running out of any of these resources. There should at
> least be something showing up in the postmaster log if we fail to open a
> file or something like that...
>
> regards, tom lane
>
> ************