From: | Rafia Sabih <rafia(dot)pghackers(at)gmail(dot)com> |
---|---|
To: | Andreas Karlsson <andreas(at)proxel(dot)se> |
Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Performance improvement for queries with IN clause |
Date: | 2019-11-11 09:14:26 |
Message-ID: | CA+FpmFf1JtEXCB8j9uV2QFjN2utwgyFD2LnegHirtcmKw-YD-A@mail.gmail.com |
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Lists: | pgsql-hackers |
On Sat, 9 Nov 2019 at 12:52, Andreas Karlsson <andreas(at)proxel(dot)se> wrote:
> On 11/8/19 2:52 PM, Rafia Sabih wrote:
> > Now, my question is shouldn't we always use this list in sorted order,
> > in other words can there be scenarios where such a sorting will not
> > help? I am talking about only the cases where the list consists of all
> > constants and could fit in memory. Basically, when we are
> > transforming the in expression and found that it consists of all
> > constants, then sort it as well, codewise at transfromAExprIn, of course
> > there might be better ways to accomplish this.
> >
> > So, your thoughts, opinions, suggestions are more than welcome.
>
> If it is worth sorting them should depend on the index, e.g. for hash
> indexes sorting would just be a waste of time.
Hi Andreas,
Thanks for your response. Here, I meant this list sorting only for Btree,
as you well pointed out that for other indexes like hash this wouldn't
really make sense.
--
Regards,
Rafia Sabih
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