Re: How to avoid transaction ID wrap - Mailing list pgsql-hackers

From Jim C. Nasby
Subject Re: How to avoid transaction ID wrap
Date
Msg-id 20060610031321.GN57289@pervasive.com
Whole thread Raw
In response to Re: How to avoid transaction ID wrap  (Trent Shipley <tshipley@deru.com>)
Responses Re: How to avoid transaction ID wrap  (Alvaro Herrera <alvherre@commandprompt.com>)
List pgsql-hackers
On Fri, Jun 09, 2006 at 06:20:21PM -0700, Trent Shipley wrote:
> Ideally, the transaction management system would be proportional to the 
> marginal change in size of the database rather than the gross size of the 
> database.  That is VACCUM being O(N) should be replaced (or there should be 
> an optional alternative) that scales with D, O^k(D) where any k > 1 involves 
> a tradeoff with VACCUM.  

That's something that's been discussed quite a bit; search the archives
for 'dead space map'. Granted, that wasn't targeted so much at the need
to VACUUM FREEZE, but there's no reason it wouldn't be possible to make
it handle that as well. In the mean time, if you partition the table on
date, you won't need to be vacuuming the entire database to handle XID
wrap.

BTW, you're also ignoring the fact that technology keeps improving the
hardware that's out there. It's possible that hardware advances alone
would keep pace with your vacuuming needs.
-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461


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