On Dec 8, 2007 3:42 AM, Andrew Dunstan <[EMAIL PROTECTED]> 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
