Re: [HACKERS] Postgres Performance

I believe that disk pages are 1k in linux systems, that would mean that
I am allocating 3M when using "postmaster -i -B 3096 -o -S 2048" and 2M
for sorting. That is very low.

However, some of the postgres processes have memory segments larger
than 3M (see bottom).

> I would imagine (Im not an expert, but through observation) that if
> you drasticly increase the number of shared memory buffers, then when
> you startup your front-end simply do a select * from the tables, it
> may even keep them all in memory from the start.

That's basically what I tried to do, but I am unable to specify a very
large number (it complained when I tried -B > ~3900). Do these buffer
contain the actual table data?
I understand that the OS is buffering the data read from disk, but
postgres is competing with all the other processes on the system. I
think that if postgres had a dedicated (user configurable) cache, like
Oracle, then users could configure the system/postgres better.

4:29pm up 83 days, 23:42, 5 users, load average: 0.00, 0.01, 0.00
75 processes: 74 sleeping, 1 running, 0 zombie, 0 stopped
CPU states: 0.1% user, 1.1% system, 0.0% nice, 98.7% idle
Mem: 128216K av, 98812K used, 29404K free, 67064K shrd, 18536K buff
Swap: 80288K av, 22208K used, 58080K free 14924K
cached

PID USER PRI NI SIZE RSS SHARE STAT LIB %CPU %MEM TIME
COMMAND
16633 postgres 0 0 26536 1384 1284 S 0 0.0 1.0 0:02
postmaster
18190 postgres 0 0 27708 3432 2720 S 0 0.0 2.6 0:00
postmaster
18303 postgres 0 0 27444 2728 2196 S 0 0.0 2.1 0:00
postmaster
18991 postgres 0 0 27472 2908 2392 S 0 0.0 2.2 0:00
postmaster
19154 postgres 0 0 27408 2644 2140 S 0 0.0 2.0 0:06
postmaster
19155 postgres 0 0 27428 2712 2188 S 0 0.0 2.1 0:00
postmaster
19157 postgres 0 0 27840 10M 10144 S 0 0.0 8.6 0:08
postmaster
19282 postgres 0 0 27560 3332 2732 S 0 0.0 2.5 0:11
postmaster
19335 postgres 0 0 27524 3112 2528 S 0 0.0 2.4 0:03
postmaster
19434 postgres 0 0 27416 2700 2192 S 0 0.0 2.1 0:00
postmaster