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RE: Re: 7.1 performance

From: "Blake, Stephen" <Stephen(dot)Blake(at)veritect(dot)com>
To: pgsql-admin(at)postgresql(dot)org
Subject: RE: Re: 7.1 performance
Date: 2001-04-30 12:59:58
Message-ID: BA23608423B8F947A7D3CC789B4BB4B80DF1E6@ADMINMAIL.corp.veritect (view raw or flat)
Thread:
Lists: pgsql-admin
Two things you should check.

1) Are you using persistent connections in your PHP scripts?
2) Are you certain your queries are utilizing the indices you have set up
for them.

For the answer to 1) check your php configuration.
For the answer to 2) do an explain on each query that is slow, making sure
it's hitting the index you think it should be.

Stephen Blake
s t e p h e n <dot/> b l a k e <at/> v e r i t e c t <dot/> c o m

-----Original Message-----
From: Thomas Heller [mailto:maniax(at)comtron(dot)net]
Sent: Thursday, April 26, 2001 12:56 PM
To: pgsql-admin(at)postgresql(dot)org
Subject: [ADMIN] Re: 7.1 performance


Hi,

> > i use the same
> > settings for sort_mem, buffers, etc. just no fsync. I thought 7.1
wouldn't
> > need that anymore.
>
> Does the behavior change if you turn off fsync again?

No.

The Database is loaded with up to 25req/s ... most of them are just simple
SELECTS (no ORDER BY, no JOINS) ... i use indexes on all important fields.
Some queries just return 1 row ... some even 1.000 ... when i run these
queries in psql they seem fast and not problematic. (i did no query
optimizing yet) Note: its a backend database to a webpage (php). There are
arround 8 postgres processes running on the machine. Through the mass of
Queries i can't really say WHO is causing the load to the machine. As the
load raised to about 17 after 1 hour online, i switched back to 7.0.3 ...
now the machine is at load 0,3 again and everything is fine.

Here are some setting from my postgresql.conf

log_connections = off
fsync = on (also off tested)
tcpip_socket = true
max_connections = 32
sort_mem = 4096
shared_buffers = 128

wal_buffers = 8
wal_files = 8
wal_sync_method = fsync
wal_debug = 0
commit_delay = 0
commit_siblings = 5
checkpoint_segments = 3
checkpoint_timeout = 300

i would really be interested in using 7.1 cause i set it up for a new
project (running a dual-p3-1ghz + 2 gig ram) and this machine really needs
good performance and i use (binary &|) which wheren't available in <7.1
afaik.

thanks,
thomas



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