On Tue, May 10, 2011 at 6:02 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Tue, May 10, 2011 at 12:57 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> Hmmm, do we really need to WAL log freezing?
>>
>> Can we break down freezing into a 2 stage process, so that we can have
>> first stage as a lossy operation and a second stage that is WAL
>> logged?
>
> That might solve the relfrozenxid problem - set the bits in the heap,
> sync the heap, then update relfrozenxid once the heap is guaranteed
> safely on disk - but it again seems problematic for Hot Standby.
How about we truncate the clog differently on each server? We could
have a special kind of VACUUM that runs during Hot Standby, setting
frozen hint bits only.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
