Re: [HACKERS] Re: vacuum timings - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] Re: vacuum timings
Date
Msg-id 200001221733.MAA21558@candle.pha.pa.us
Whole thread Raw
In response to RE: [HACKERS] Re: vacuum timings  ("Hiroshi Inoue" <Inoue@tpf.co.jp>)
List pgsql-hackers
> > Quite a few people have reported finding the opposite in practice.
> > You should probably try vacuuming after deleting or updating some
> > fraction of the rows, rather than just the all or none cases.
> >
> 
> Vacuum after delelting all rows isn't a worst case.
> There's no moving in that case and vacuum doesn't need to call
> index_insert() corresponding to the moving of heap tuples.
> 
> Vacuum after deleting half of rows may be one of the worst case.
> In this case,index_delete() is called as many times as 'delete all'
> case and expensive index_insert() is called for moved_in tuples.

I will test that.

--  Bruce Momjian                        |  http://www.op.net/~candle pgman@candle.pha.pa.us               |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 


pgsql-hackers by date:

Previous
From: Byron Nikolaidis
Date:
Subject: Re: [INTERFACES] Re: ODBC drive strange behavior
Next
From: Bruce Momjian
Date:
Subject: Re: [HACKERS] off topic