Re: Apache + PHP + Postgres Interaction

From: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
To: Max Zorloff <zorloff(at)gmail(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Apache + PHP + Postgres Interaction
Date: 2007-08-23 17:16:48
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Max Zorloff wrote:
> Hello.
> I have a subject setup and a few questions.
> The first one is this. PHP establishes a connection to the Postgres
> database through pg_pconnect().

Don't use pconnect. Use pgbouncer or pgpool.

> Then it
> runs some query, then the script returns, leaving the persistent
> connection hanging. But the trouble
> is that in this case any query takes significantly more time to execute
> than in the case of one PHP script
> running the same query with different parameters for N times. How can I
> achieve the same performance in the first
> case? Persistent connections help but not enough - the queries are still
> 10 times slower than they would be on
> the 2nd time.

Well you haven't given us any indication of data set or what you are
trying to do. However, I can tell you, don't use pconnect, its broke ;)

> The second one is that the machine with this setup is dual core Xeon
> 2.8ghz. I've read somewhere about
> the switching context problem and bad postgres performance. What are the
> effects? What are the symptoms?

You likely do not have this problem if you are running anywhere near a
current PostgreSQL release but you can check it with vmstat.

> And what will be the performance gain if I change the machine to equal
> Athlon?

Depends on the work load.


Joshua D. Drake

> Thank you in advance.
> ---------------------------(end of broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster

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