Re: Any better plan for this query?..

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: "Dimitri" <dimitrik(dot)fr(at)gmail(dot)com>,"Robert Haas" <robertmhaas(at)gmail(dot)com>
Cc: "Simon Riggs" <simon(at)2ndquadrant(dot)com>,"Alvaro Herrera" <alvherre(at)commandprompt(dot)com>,"Merlin Moncure" <mmoncure(at)gmail(dot)com>,"Dimitri Fontaine" <dfontaine(at)hi-media(dot)com>,"Aidan Van Dyk" <aidan(at)highrise(dot)ca>,"PostgreSQL Performance" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Any better plan for this query?..
Date: 2009-05-12 15:46:37
Views: Raw Message | Whole Thread | Download mbox
Lists: pgsql-performance

Dimitri <dimitrik(dot)fr(at)gmail(dot)com> wrote:

> Of course the Max throughput is reached on the number of users equal
> to 2 * number of cores

I'd expect that when disk I/O is not a significant limiting factor,
but I've seen a "sweet spot" of (2 * cores) + (effective spindle
count) for loads involving a lot of random I/O.

> So, do I really need a pooler to keep 256 users working??

I have seen throughput fall above a certain point when I don't use a
connection pooler. With a connection pooler which queues requests
when all connections are busy, you will see no throughput degradation
as users of the pool are added. Our connection pool is in our
framework, so I don't know whether pgbouncer queues requests.
(Perhaps someone else can comment on that, and make another suggestion
if it doesn't.)


In response to

Browse pgsql-performance by date

  From Date Subject
Next Message Joshua D. Drake 2009-05-12 16:07:59 Re: Any better plan for this query?..
Previous Message Dimitri 2009-05-12 15:41:14 Re: What is the most optimal config parameters to keep stable write TPS ?..