<br /><br /><div class="gmail_quote">On Dec 8, 2007 3:42 AM, Andrew Dunstan <<a
href="mailto:andrew@dunslane.net">andrew@dunslane.net</a>>wrote:<br /><blockquote class="gmail_quote"
style="border-left:1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="Ih2E3d"><br
/><br/>Bruce Momjian wrote:<br />> Andrew Dunstan wrote:<br />><br />>>>> I still think this needs to
bequalified either way. As it stands it's<br />>>>> quite misleading. Many update scenarios will not
benefitone whit from <br />>>>> HOT updates.<br />>>>><br />>>>><br />>>>
Doesn'tthe detail description qualify it enought? The heading isn't<br />>>> suppose to have all the
informationor it would be unreadable. <br />>>><br />>>><br />>>><br />>> If you don't
wantto be more specific I'd say "certain updates" or "some<br />>> updates" or something similar, just some flag
tosay it's not all of them. <br />>><br />><br />> Good idea. I added "most":<br />><br />>
Heap-OnlyTuples (<acronym>HOT</>) accelerate space reuse for most<br />>
<command>UPDATE</>s(Pavan Deolasee, with ideas from many others) <br />><br /><br /></div>But that's
nottrue either. For example, in my current $dayjob app not<br />one significant update will benefit - we have an index
richenvironment.<br />You have no basis for saying "most" that I can see. We really should not <br />be in the hyp
businessin our release notes - that job belongs to the<br />commercial promoters ;-)<br /><div class="Ih2E3d"><br /><br
/></div></blockquote></div><br/><br />I don't agree completely. HOT updates is just one significant benefit of <br
/>HOTand is constrained by the non-index column updates. But the other<br />major benefit of truncating the tuples to
theirline pointers applies to<br />HOT as well as COLD updates and DELETEs. This should also have<br />a non trivial
positiveimpact on the performance. <br /><br />There might be few scenarios where HOT may not show any improvement<br
/>suchas CPU-bound applications, but I am not sure if its worth mentioning.<br /><br />Thanks,<br />Pavan<br /><br
clear="all"/><br />-- <br />Pavan Deolasee <br />EnterpriseDB <a
href="http://www.enterprisedb.com">http://www.enterprisedb.com</a>
