To: "Jeffrey W. Baker" <jwbaker@acm.org>
Cc: karim.nassar@acm.org, pgsql-performance@postgresql.org
Subject: Re: What's a lot of connections? 
In-reply-to: <1121411682.7733.0.camel@noodles> 
References: <1121410859.4715.87.camel@localhost.localdomain>
	<1121411682.7733.0.camel@noodles>
Comments: In-reply-to "Jeffrey W. Baker" <jwbaker@acm.org>
	message dated "Fri, 15 Jul 2005 00:14:42 -0700"
Date: Fri, 15 Jul 2005 10:16:16 -0400
Message-ID: <11126.1121436976@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

"Jeffrey W. Baker" <jwbaker@acm.org> writes:
> On Fri, 2005-07-15 at 00:00 -0700, Karim Nassar wrote:
>> I am working on a system that uses postgresql 7.4.2 (can't change that
>> until 8.1 goes stable). Just figured out that there are about 285,000
>> connections created over about 11 hours every day. That averages out to
>> about 7.2 connections per second.
>> 
>> Is that a lot? I've never seen that many.

> I see about 8 million connections per full day.  Connecting to postgres
> is cheap.

It's not *that* cheap.  I think you'd get materially better performance
if you managed to pool your connections a bit.  By the time a backend
has started, initialized itself, joined a database, and populated its
internal caches with enough catalog entries to get useful work done,
you've got a fair number of cycles invested in it.  Dropping the backend
after only one or two queries is just not going to be efficient.

			regards, tom lane