Re: Large database help

I'm spawning 6 backends to query the data. top lists 6 postmaster processes
working, and therefore the idle time should hit 0% easily. Also, the hard
drive light goes nuts when I'm running this.

Here is the pertinent information from top. To be clear, I'm NOT spawning a
new postmaster per chunk. These same six processes are alive and kicking
for over 4 minutes.

I hope the formatting works ok.

PID USER PRI NI SIZE RSS SHARE STAT LIB %CPU %MEM TIME COMMAND
2379 mg 13 0 14476 14M 12908 S 0 5.8 2.7 0:01 postmaster
2380 mg 10 0 14436 14M 12868 S 0 2.9 2.7 0:01 postmaster
2381 mg 10 0 13572 13M 12012 S 0 2.9 2.6 0:00 postmaster
2377 mg 10 0 13640 13M 12072 S 0 2.4 2.6 0:01 postmaster
2378 mg 11 0 14476 14M 12908 S 0 2.4 2.7 0:01 postmaster
2376 mg 8 0 13556 13M 11984 S 0 1.9 2.6 0:00 postmaster

27 processes: 24 sleeping, 3 running, 0 zombie, 0 stopped
CPU states: 16.3% user, 3.8% system, 0.0% nice, 79.8% idle
Mem: 517292K av, 508400K used, 8892K free, 94444K shrd, 197224K buff
Swap: 65988K av, 0K used, 65988K free 160740K cached

-Xavier

At 12:46 AM 4/23/01 +0200, Ragnar Kjørstad wrote:
>On Sun, Apr 22, 2001 at 05:12:20PM -0400, xbdelacour(at)yahoo(dot)com wrote:
> > My problem is this: during the query process the hard drive is being
> tagged
> > excessively, while the cpu's are idling at 50% (numbers from Linux
> command:
> > top), and this is bringing down the speed pretty dramatically since the
> > process is waiting on the hard disk. How do I get the database to be
> > completely resident in memory such that selects don't cause hdd activity?
> > How do I pin how exactly why the hard disk is being accessed?
>
>50% idle on a 2 CPU system mean one CPU is busy and one is idle - as
>expected if you run a single CPU-intensive job.
>
> > I am setting 'echo 402653184 >/proc/sys/kernel/shmmax', which is being
> > reflected in top. I also specify '-B 48000' when starting postmaster. My
> > test DB is only 86MB, so in theory the disk has no business being active
> > once the data is read into memory unless I perform a write operation..
> What
> > am I missing?
>
>What does top say?
>How much memory do each of your postgres processes take, and how much of
>it is shared?
>Is there any free memory?
>
>
>--
>Ragnar Kjørstad

_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com