Re: [GENERAL] Autovacuum Improvements

Kenneth Marshall <ktm@it.is.rice.edu>

From: Kenneth Marshall <ktm@it.is.rice.edu>
To: Jim Nasby <jim@nasby.net>
Cc: Ron Mayer <rm_pg@cheapcomplexdevices.com>, Gregory Stark <stark@enterprisedb.com>, pgsql-hackers@postgresql.org
Date: 2007-01-24T13:40:31Z
Lists: pgsql-hackers
On Tue, Jan 23, 2007 at 09:01:41PM -0600, Jim Nasby wrote:
> On Jan 22, 2007, at 6:53 PM, Kenneth Marshall wrote:
> >The default should
> >be approximately the OS standard read-ahead amount.
> 
> Is there anything resembling a standard across the OSes we support?  
> Better yet, is there a standard call that allows you to find out what  
> the read-ahead setting is?
> --
> Jim Nasby                                            jim@nasby.net
> EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)
> 
Not that I am aware of. Even extending the relation by one additional
block can make a big difference in performance and should easily fall
within every read-ahead in use today. Or a GUC variable, that defaults
to a small power of 2 number of PostgreSQL blocks, with a default arrived
at by testing.

Ken