| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
| Cc: | Andrew Dunstan <andrew(at)dunslane(dot)net>, "naman(dot)iitb" <naman(dot)bbps(at)gmail(dot)com>, PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Creating Empty Index |
| Date: | 2013-11-03 03:01:07 |
| Message-ID: | 22979.1383447667@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Michael Paquier <michael(dot)paquier(at)gmail(dot)com> writes:
> On Sat, Nov 2, 2013 at 10:28 PM, Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:
>> What exactly would be the point? Indexes are automatically maintained by
>> postgres. Something that isn't doesn't seem to me to qualify for the
>> description of "index".
> Perhaps an index without data that could be used by the planner for
> automatic query tuning to evaluate how a query could run if the index
> exists? Like the concept of hypothetical indexes or something like the
> possibility to do a CREATE/ALTER INDEX ... WITH [ NO ] DATA.
But we already provide support for hypothetical indexes via planner
plugins. Why would you need an actual empty index underlying that?
I agree with Andrew that the use-case for this hasn't been explained.
regards, tom lane
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