From: Simon Riggs <simon@2ndQuadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org
Subject: Re: enable_joinremoval
Date: Mon, 29 Mar 2010 19:17:55 +0100
Message-ID: <1269886675.3684.4064.camel@ebony> (raw)
In-Reply-To: <14201.1269877615@sss.pgh.pa.us>
References: <1269851630.3684.3636.camel@ebony>
<603c8f071003290637q14d431f7j90afabd6fd2ec952@mail.gmail.com>
<12679.1269873374@sss.pgh.pa.us>
<603c8f071003290820h3553d223le3b5228f789608f9@mail.gmail.com>
<13795.1269876446@sss.pgh.pa.us>
<603c8f071003290832u23130f2x84ffa459e312269c@mail.gmail.com>
<14201.1269877615@sss.pgh.pa.us>
On Mon, 2010-03-29 at 11:46 -0400, Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > OK, I'll write a patch for that; and a consensus emerges that we
> > should also have enable_joinremoval, then I will add that as well. I
> > think the only argument for NOT having enable_joinremoval is that you
> > can always modify the query to say SELECT * rather than some more
> > specific SELECT list,
>
> Uh, no, the argument for not having enable_joinremoval is that it's
> useless.
>
> In particular, I categorically deny the argument that putting it in will
> reduce user confusion. If anyone is confused because EXPLAIN shows that
> some table isn't getting joined to, you think that the fact that
> somewhere in the manual is a mention of enable_joinremoval will
> un-confuse them? If they knew that switch was there or what it did,
> they wouldn't be confused to begin with.
You're not addressing the original point. I have been asked how would
users know which tables have been removed and whether there is a way of
checking that. That is not a request for a tuning feature, or something
to reduce user confusion. If you don't like "enable_joinremoval" that's
fine but it would be good to answer the original request with an
alternative proposal.
--
Simon Riggs www.2ndQuadrant.com
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: simon@2ndQuadrant.com, tgl@sss.pgh.pa.us, robertmhaas@gmail.com
Subject: Re: enable_joinremoval
In-Reply-To: <1269886675.3684.4064.camel@ebony>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox