Skip site navigation (1) Skip section navigation (2)

Re: planner/optimizer question

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: josh(at)agliodbs(dot)com
Cc: "Gary Doades" <gpd(at)gpdnet(dot)co(dot)uk>,pgsql-performance(at)postgresql(dot)org
Subject: Re: planner/optimizer question
Date: 2004-04-29 23:17:49
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-performance
Josh Berkus <josh(at)agliodbs(dot)com> writes:
> Certainly the fact that MSSQL is essentially a single-user database makes 
> things easier for them.

Our recent testing (cf the "Xeon" thread) says that the interlocking we
do to make the world safe for multiple backends has a fairly high cost
(at least on some hardware) compared to the rest of the work in
scenarios where you are doing zero-I/O scans of data already in memory.
Especially so for index scans.  I'm not sure this completely explains
the differential that Gary is complaining about, but it could be part of
it.  Is it really true that MSSQL doesn't support concurrent operations?

			regards, tom lane

In response to


pgsql-performance by date

Next:From: Joseph ShraibmanDate: 2004-04-29 23:19:09
Subject: why can't 2 indexes be used at once?
Previous:From: Joseph ShraibmanDate: 2004-04-29 23:09:09
Subject: analyzer/planner and clustered rows

Privacy Policy | About PostgreSQL
Copyright © 1996-2017 The PostgreSQL Global Development Group