Re: Hypothetical Indexes - PostgreSQL extension - PGCON 2010

Hackers,

We would like to inform you all that our extension to PostgreSQL, that
includes hypothetical indexes (and soon index self-tuning), is
available through a sourgeforge project.
This was suggested at PgCon 2010 and we hope some of you may find it
useful, contribute and give us your feedback.

Link to project:
http://sourceforge.net/projects/hypotheticalind/

Thanks,
Sergio Lifschitz
Ana Carolina Almeida

Ana,

> We would like to inform you all that our extension to PostgreSQL, that includes hypothetical indexes (and soon index self-tuning), is available through a sourgeforge project.
> This was suggested at PgCon 2010 and we hope some of you may find it useful, contribute and give us your feedback.

Great to see this being available finally!

--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com

On 2010-12-02 00:48, Ana Carolina Brito de Almeida wrote:

> We would like to inform you all that our extension to PostgreSQL, that includes hypothetical indexes (and soon index self-tuning), is available through a sourgeforge project.
> This was suggested at PgCon 2010 and we hope some of you may find it useful, contribute and give us your feedback.

Looking at the sourceforge page, I'm left with one burning question:
what are they for?

I can see what a hypothetical index is, but neither the project pages
nor the README in the tarball say why I might want one. I'd be quite
interested to know that.

Jeroen

On 03/12/10 08:14, Jeroen Vermeulen wrote:
> On 2010-12-02 00:48, Ana Carolina Brito de Almeida wrote:
>
>> We would like to inform you all that our extension to PostgreSQL, that
>> includes hypothetical indexes (and soon index self-tuning), is
>> available through a sourgeforge project.

> Looking at the sourceforge page, I'm left with one burning question:
> what are they for?

I believe they're for performance testing. Add hypothetical index (takes
very little time). Check estimated costs with EXPLAIN. If good, add real
index (takes lots of time).

Of course, they're also good for indexing hypothetical data ;-)

--
Richard Huxton
Archonet Ltd

Indeed, hypothetical indexes are good to check potentially good
configurations without harming the whole system with actual index
creation. Please observer that we've added an "explain hypothetical"
command, that will include plans considering hypothetical indexes! We'll
try to add a simple case study that would help those wondering about
this project.

Sergio

On 3/12/2010 08:06, Richard Huxton wrote:
> On 03/12/10 08:14, Jeroen Vermeulen wrote:
>> On 2010-12-02 00:48, Ana Carolina Brito de Almeida wrote:
>>
>>> We would like to inform you all that our extension to PostgreSQL, that
>>> includes hypothetical indexes (and soon index self-tuning), is
>>> available through a sourgeforge project.
>
>> Looking at the sourceforge page, I'm left with one burning question:
>> what are they for?
>
> I believe they're for performance testing. Add hypothetical index
> (takes very little time). Check estimated costs with EXPLAIN. If good,
> add real index (takes lots of time).
>
> Of course, they're also good for indexing hypothetical data ;-)
>

On 2010-12-03 19:44, Sergio Lifschitz wrote:
> Indeed, hypothetical indexes are good to check potentially good
> configurations without harming the whole system with actual index
> creation. Please observer that we've added an "explain hypothetical"
> command, that will include plans considering hypothetical indexes! We'll
> try to add a simple case study that would help those wondering about
> this project.

That sounds very useful indeed!

Jeroen

Jeroen,

We add a simple case study (sourceforge page):
http://sourceforge.net/projects/hypotheticalind/files/TUTORIAL_8_4.pdf/download

Although this tutorial is for version 8.4, it also applies to other
versions.

Att,
Ana Carolina

2010/12/3 Jeroen Vermeulen <jtv(at)xs4all(dot)nl>

> On 2010-12-03 19:44, Sergio Lifschitz wrote:
>
>> Indeed, hypothetical indexes are good to check potentially good
>> configurations without harming the whole system with actual index
>> creation. Please observer that we've added an "explain hypothetical"
>> command, that will include plans considering hypothetical indexes! We'll
>> try to add a simple case study that would help those wondering about
>> this project.
>>
>
> That sounds very useful indeed!
>
>
> Jeroen
>

On 2010-12-03 20:49, Ana Carolina Brito de Almeida wrote:

> We add a simple case study (sourceforge page):
> http://sourceforge.net/projects/hypotheticalind/files/TUTORIAL_8_4.pdf/download

Great, thanks!

I'll try to write a bit more about it later:

http://pqxx.org/development/libpqxx/wiki/HypotheticalIndexes

Jeroen