Re: Updates on large tables are extremely slow

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От Tom Lane
Тема Re: Updates on large tables are extremely slow
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Msg-id 19628.1118673136@sss.pgh.pa.us
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Ответ на Re: Updates on large tables are extremely slow  (Yves Vindevogel <yves.vindevogel@implements.be>)
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Yves Vindevogel <yves.vindevogel@implements.be> writes:
> rvponp=3D# vacuum verbose tblPrintjobs ;
> INFO:  vacuuming "public.tblprintjobs"
> [ twenty-one different indexes on one table ]

Well, there's your problem.  You think updating all those indexes is
free?  It's *expensive*.  Heed the manual's advice: avoid creating
indexes you are not certain you need for identifiable commonly-used
queries.

(The reason delete is fast is it doesn't have to touch the indexes ...
the necessary work is left to be done by VACUUM.)

            regards, tom lane

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