Pavan Deolasee wrote:
On Dec 8, 2007 3:42 AM, Andrew Dunstan <[EMAIL PROTECTED]
<mailto:[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.
<http://www.enterprisedb.com>
Um, I don't understand. I freely admit that I haven't kept up with all
the nuances of the HOT discussions, but this bit has totally eluded me,
so please elucidate.
cheers
andrew
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