Tuning Techniques To Avoid?
От | Christopher Browne |
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Тема | Tuning Techniques To Avoid? |
Дата | |
Msg-id | m37k0aa5sl.fsf@wolfe.cbbrowne.com обсуждение исходный текст |
Ответ на | Why memory is not used ? Why vacuum so slow ? (Hervé Piedvache <herve@elma.fr>) |
Ответы |
Re: Tuning Techniques To Avoid?
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Список | pgsql-performance |
Here's a scheme for query optimization that probably needs to be avoided in that it would run afoul of a patent held by Oracle... <http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=5761654.WKU.&OS=PN/5761654&RS=PN/5761654> It looks like what they have patented is pretty much a "greedy search" heuristic, starting by finding the table in a join that has the greatest selectivity (e.g. - where the number of entries selected is cut the most by the selection criteria), and then describes how to search for the "best" approach to joining in the other tables. -- output = reverse("gro.mca" "@" "enworbbc") http://www.ntlug.org/~cbbrowne/nonrdbms.html "If I could find a way to get [Saddam Hussein] out of there, even putting a contract out on him, if the CIA still did that sort of a thing, assuming it ever did, I would be for it." -- Richard M. Nixon
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