Re: Indirect indexes

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

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