Re: Experimental patch for inter-page delay in VACUUM - Mailing list pgsql-hackers

From Zeugswetter Andreas SB SD
Subject Re: Experimental patch for inter-page delay in VACUUM
Date
Msg-id 46C15C39FEB2C44BA555E356FBCD6FA4962057@m0114.s-mxs.net
Whole thread Raw
In response to Experimental patch for inter-page delay in VACUUM  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Experimental patch for inter-page delay in VACUUM  (Andreas Pflug <pgadmin@pse-consulting.de>)
List pgsql-hackers
> Or...  It seems to me that we have been observing something on the order
> of 10x-20x slowdown for vacuuming a table.  I think this is WAY
> overcompensating for the original problems, and would cause it's own
> problem as mentioned above.   Since the granularity of delay seems to be
> the problem can we do more work between delays? Instead of sleeping
> after every page (I assume this is what it's doing) perhaps we should
> sleep every 10 pages,

I also think doing more than one page per sleep is advantageous since
it would still allow the OS to do it's readahead optimizations.
I suspect those would fall flat if only one page is fetched per sleep.

Andreas


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