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Message-ID: <33c6269f05052416122096eb1e@mail.gmail.com>
Date: Tue, 24 May 2005 19:12:14 -0400
From: Alex Turner <armtuk@gmail.com>
Reply-To: Alex Turner <armtuk@gmail.com>
To: Bruno Wolff III <bruno@wolff.to>,
	mark durrant <markd89@yahoo.com>, pgsql-performance@postgresql.org
Subject: Re: Select performance vs. mssql
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Until you start worrying about MVC - we have had problems with the MSSQL=20
implementation of read consistency because of this 'feature'.

Alex Turner
NetEconomist

On 5/24/05, Bruno Wolff III <bruno@wolff.to> wrote:
>=20
> On Tue, May 24, 2005 at 08:36:36 -0700,
> mark durrant <markd89@yahoo.com> wrote:
> >
> > --MSSQL's ability to hit the index only and not having
> > to go to the table itself results in a _big_
> > performance/efficiency gain. If someone who's in
> > development wants to pass this along, it would be a
> > nice addition to PostgreSQL sometime in the future.
> > I'd suspect that as well as making one query faster,
> > it would make everything else faster/more scalable as
> > the server load is so much less.
>=20
> This gets brought up a lot. The problem is that the index doesn't include
> information about whether the current transaction can see the referenced
> row. Putting this information in the index will add significant overhead
> to every update and the opinion of the developers is that this would be
> a net loss overall.
>=20
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>

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Until you start worrying about MVC - we have had problems with the
MSSQL implementation of read consistency because of this 'feature'.<br>
<br>
Alex Turner<br>
NetEconomist<br><br><div><span class=3D"gmail_quote">On 5/24/05, <b class=
=3D"gmail_sendername">Bruno Wolff III</b> &lt;<a href=3D"mailto:bruno@wolff=
.to">bruno@wolff.to</a>&gt; wrote:</span><blockquote class=3D"gmail_quote" =
style=3D"border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8=
ex; padding-left: 1ex;">
On Tue, May 24, 2005 at 08:36:36 -0700,<br>&nbsp;&nbsp;mark durrant &lt;<a =
href=3D"mailto:markd89@yahoo.com">markd89@yahoo.com</a>&gt; wrote:<br>&gt;<=
br>&gt; --MSSQL's ability to hit the index only and not having<br>&gt; to g=
o to the table itself results in a _big_
<br>&gt; performance/efficiency gain. If someone who's in<br>&gt; developme=
nt wants to pass this along, it would be a<br>&gt; nice addition to Postgre=
SQL sometime in the future.<br>&gt; I'd suspect that as well as making one =
query faster,
<br>&gt; it would make everything else faster/more scalable as<br>&gt; the =
server load is so much less.<br><br>This gets brought up a lot. The problem=
 is that the index doesn't include<br>information about whether the current=
 transaction can see the referenced
<br>row. Putting this information in the index will add significant overhea=
d<br>to every update and the opinion of the developers is that this would b=
e<br>a net loss overall.<br><br>---------------------------(end of broadcas=
t)---------------------------
<br>TIP 4: Don't 'kill -9' the postmaster<br></blockquote></div><br>

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