Re: Slow count(*) again...

From: Jesper Krogh <jesper(at)krogh(dot)cc>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Neil Whelchel <neil(dot)whelchel(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Slow count(*) again...
Date: 2010-10-13 17:59:48
Message-ID: 4CB5F394.6090909@krogh.cc
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On 2010-10-13 15:28, Robert Haas wrote:
> On Wed, Oct 13, 2010 at 6:16 AM, Neil Whelchel<neil(dot)whelchel(at)gmail(dot)com> wrote:
>
>> I might go as far as to rattle the cage of the developers to see if it makes
>> any sense to add some column oriented storage capability to Postgres. That
>> would be the hot ticket to be able to specify an attribute on a column so that
>> the back end could shadow or store a column in a column oriented table so
>> aggregate functions could work on them with good efficiency, or is that an
>> INDEX?
>>
> I'd love to work on that, but without funding it's tough to find the
> time. It's a big project.
>
Is it hugely different from just getting the visibillity map suitable
for doing index-only scans and extracting values from the index
directly as Heikki has explained?

That would essentially do a column oriented table (the index itself)
of a specific columns (or column set).

... still a huge task though.

--
Jesper

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