From: Bruce Momjian <bruce@momjian.us>
To: Pavan Deolasee <pavan.deolasee@gmail.com>
Cc: Alexander Korotkov <a.korotkov@postgrespro.ru>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Indirect indexes
Date: Wed, 19 Oct 2016 12:40:43 -0400
Message-ID: <20161019164043.GN5087@momjian.us> (raw)
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On Wed, Oct 19, 2016 at 07:23:28PM +0530, Pavan Deolasee wrote:
> AFAICS, even without considering VACUUM, indirect indexes would be always
> used with recheck.
> As long as they don't contain visibility information. When indirect
> indexed column was updated, indirect index would refer same PK with
> different index keys.
> There is no direct link between indirect index tuple and heap tuple, only
> logical link using PK. Thus, you would anyway have to recheck.
>
>
>
> I agree. Also, I think the recheck mechanism will have to be something like
> what I wrote for WARM i.e. only checking for index quals won't be enough and we
> would actually need to verify that the heap tuple satisfies the key in the
> indirect index.
I personally would like to see how far we get with WARM before adding
this feature that requires a DBA to evaluate and enable it.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ As you are, so once was I. As I am, so you will be. +
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Cc: bruce@momjian.us, pavan.deolasee@gmail.com, a.korotkov@postgrespro.ru, robertmhaas@gmail.com, alvherre@2ndquadrant.com
Subject: Re: Indirect indexes
In-Reply-To: <20161019164043.GN5087@momjian.us>
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