Re: Turning off HOT/Cleanup sometimes

On 15 September 2014 22:13, Simon Riggs <simon@2ndquadrant.com> wrote:
> On 15 September 2014 17:09, Robert Haas <robertmhaas@gmail.com> wrote:
>
>> Do we really want to disable HOT for all catalog scans?
>
> The intention of the patch is that catalog scans are treated
> identically to non-catalog scans. The idea here is that HOT cleanup
> only occurs on scans on target relations, so only INSERT, UPDATE and
> DELETE do HOT cleanup.

Since INSERT, UPDATE and DELETE can only be called when
!RecoveryInProgress(), we can completely avoid making this test at the
top of each heap_page_prune_opt() call.

I very much like the simplicity of saying "no target, no cleanup".

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services