Re: Indirect indexes - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Indirect indexes
Date
Msg-id 20161019164043.GN5087@momjian.us
Whole thread Raw
In response to Re: Indirect indexes  (Pavan Deolasee <pavan.deolasee@gmail.com>)
Responses Re: Indirect indexes  (Simon Riggs <simon@2ndquadrant.com>)
List pgsql-hackers
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. +
+                      Ancient Roman grave inscription +



pgsql-hackers by date:

Previous
From: Greg Stark
Date:
Subject: Re: [COMMITTERS] packing/alignment annotation for ItemPointerData redux
Next
From: Bruce Momjian
Date:
Subject: Re: Move pg_largeobject to a different tablespace *without* turning on system_table_mods.