Re: Release Note Changes

On Dec 8, 2007 3:42 AM, Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:

>
>
> Bruce Momjian wrote:
> > Andrew Dunstan wrote:
> >
> >>>> I still think this needs to be qualified either way. As it stands
> it's
> >>>> quite misleading. Many update scenarios will not benefit one whit
> from
> >>>> HOT updates.
> >>>>
> >>>>
> >>> Doesn't the detail description qualify it enought? The heading isn't
> >>> suppose to have all the information or it would be unreadable.
> >>>
> >>>
> >>>
> >> If you don't want to be more specific I'd say "certain updates" or
> "some
> >> updates" or something similar, just some flag to say it's not all of
> them.
> >>
> >
> > Good idea. I added "most":
> >
> > Heap-Only Tuples (<acronym>HOT</>) accelerate space reuse for
> most
> > <command>UPDATE</>s (Pavan Deolasee, with ideas from many others)
> >
>
> But that's not true either. For example, in my current $dayjob app not
> one significant update will benefit - we have an index rich environment.
> You have no basis for saying "most" that I can see. We really should not
> be in the hyp business in our release notes - that job belongs to the
> commercial promoters ;-)
>
>
>

I don't agree completely. HOT updates is just one significant benefit of
HOT and is constrained by the non-index column updates. But the other
major benefit of truncating the tuples to their line pointers applies to
HOT as well as COLD updates and DELETEs. This should also have
a non trivial positive impact on the performance.

There might be few scenarios where HOT may not show any improvement
such as CPU-bound applications, but I am not sure if its worth mentioning.

Thanks,
Pavan

--
Pavan Deolasee
EnterpriseDB http://www.enterprisedb.com