Обсуждение: postgres getting slow

I noticed that on our postgres server, when more than say 15-20 backends
are open at once, things start to get real slow.  System is:

Redhat 5.2 Linux
2.2.8 kernel
Postgres 6.3.2
PII 450
256MB RAM

Does anyone know why this may be?

Also I can't seem to get postgres to write to a log about what it is
doing, whats the best way to get it to do this, so that any
errors/warnings get logged?

Brian


-----------------------------------------------------
Brian Feeny (BF304)     signal@shreve.net
318-222-2638 x 109    http://www.shreve.net/~signal
Network Administrator   ShreveNet Inc. (ASN 11881)

> I noticed that on our postgres server, when more than say 15-20 backends
> are open at once, things start to get real slow.  System is:
>
> Redhat 5.2 Linux
> 2.2.8 kernel
> Postgres 6.3.2
> PII 450
> 256MB RAM
>
> Does anyone know why this may be?

Hmmm... I'm trying to optimize Postgres as much as I can right now.  I
usually have 4 or 5 backends running, some under CGI and some under ODBC.
I notice the ODBC (via Access) seems to monopolize the database,
especially when doing updates.

> Also I can't seem to get postgres to write to a log about what it is
> doing, whats the best way to get it to do this, so that any
> errors/warnings get logged?

I have something like this in my startup script appended to the invocation
of the postmaster ( as we discussed yesterday):

>> ${PGLOGFILE} 2>&1

where $PGLOGFILE is a path to postgres.log.

Brett W. McCoy
                                        http://www.lan2wan.com/~bmccoy/
-----------------------------------------------------------------------
"One basic notion underlying Usenet is that it is a cooperative."

Having been on USENET for going on ten years, I disagree with this.
The basic notion underlying USENET is the flame.
        -- Chuq Von Rospach

>
> I have something like this in my startup script appended to the invocation
> of the postmaster ( as we discussed yesterday):
>
> >> ${PGLOGFILE} 2>&1
>
> where $PGLOGFILE is a path to postgres.log.
>

What sort of things to do you catch with logging this?  I haven't seen a
single thing goto this file since starting it:

export PGLOGFILE=/var/lib/pgsql/pg.log
su postgres -c '/usr/bin/postmaster -B 250 -i -S -D/var/lib/pgsql -o -S 1024 >> ${PGLOGFILE} 2>&1'

[signal@norad signal]$ ls -al /var/lib/pgsql/pg.log
-rw-rw-r--   1 postgres postgres        0 May 14 11:31 /var/lib/pgsql/pg.log


> Brett W. McCoy
>                                         http://www.lan2wan.com/~bmccoy/
> -----------------------------------------------------------------------
> "One basic notion underlying Usenet is that it is a cooperative."
>
> Having been on USENET for going on ten years, I disagree with this.
> The basic notion underlying USENET is the flame.
>         -- Chuq Von Rospach
>

-----------------------------------------------------
Brian Feeny (BF304)     signal@shreve.net
318-222-2638 x 109    http://www.shreve.net/~signal
Network Administrator   ShreveNet Inc. (ASN 11881)

At 21:51 +0300 on 20/05/1999, Brian wrote:


> What sort of things to do you catch with logging this?  I haven't seen a
> single thing goto this file since starting it:
>
> export PGLOGFILE=/var/lib/pgsql/pg.log
> su postgres -c '/usr/bin/postmaster -B 250 -i -S -D/var/lib/pgsql -o -S
>1024 >> ${PGLOGFILE} 2>&1'

I usually add "-d 2" to my postmaster invocation. It puts a lot of
information in the logfile, although I must say I've never been happy about
Postgres's logs. If you want to see where an error has occured, the actual
query is buried within many internal messages.

Herouth

--
Herouth Maoz, Internet developer.
Open University of Israel - Telem project
http://telem.openu.ac.il/~herutma