Re: Visibility map, partial vacuums - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Visibility map, partial vacuums
Date
Msg-id 1225193108.3971.154.camel@ebony.2ndQuadrant
Whole thread Raw
In response to Visibility map, partial vacuums  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Responses Re: Visibility map, partial vacuums
List pgsql-hackers
On Mon, 2008-10-27 at 14:03 +0200, Heikki Linnakangas wrote:
> One option would be to just ignore that problem for now, and not 
> WAL-log.

Probably worth skipping for now, since it will cause patch conflicts if
you do. Are there any other interactions with Hot Standby? 

But it seems like we can sneak in an extra flag on a HEAP2_CLEAN record
to say "page is now all visible", without too much work.

Does the PD_ALL_VISIBLE flag need to be set at the same time as updating
the VM? Surely heapgetpage() could do a ConditionalLockBuffer exclusive
to set the block flag (unlogged), but just not update VM. Separating the
two concepts should allow the visibility check speed gain to more
generally available. 

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support



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