Re: HOT for PostgreSQL 8.3 - Mailing list pgsql-hackers

From Pavan Deolasee
Subject Re: HOT for PostgreSQL 8.3
Date
Msg-id 2e78013d0702111035q2058dfbdi1b04fb1ec5667906@mail.gmail.com
Whole thread Raw
In response to Re: HOT for PostgreSQL 8.3  (Hannu Krosing <hannu@skype.net>)
Responses Re: HOT for PostgreSQL 8.3  (Heikki Linnakangas <heikki@enterprisedb.com>)
List pgsql-hackers

On 2/11/07, Hannu Krosing <hannu@skype.net> wrote:
Ühel kenal päeval, P, 2007-02-11 kell 12:35, kirjutas Tom Lane:
> Hannu Krosing <hannu@skype.net> writes:
> > What if we would just reuse the root tuple directly instead of turning
> > it into a stub ?
> > This would create a cycle of ctid pointers, which changes the lookup
> > process from 'follow ctid chaint until the end' to 'follow the tid chain
> > until you reach the start'.
>
> How do you know which one is newest?

By xmin,cmin of course .

This sounds interesting. But we might have trouble supporting HOT-update when
tuple length changes. May be we can release the space consumed by the dead root
tuple and have fresh allocation if the tuple length increases.


Thanks,
Pavan

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