Simon Riggs wrote:
> On Wed, 2009-02-25 at 22:39 +0200, Heikki Linnakangas wrote:
>
>> When we take the snapshot of running transactions in the master, in
>> GetRunningTransactionData(), it only includes top-level xids and those
>> subxids that are in the subxid caches. Overflowed subxids are not
>> included. Isn't that a problem? When the standby initializes the
>> recovery procs using the running xacts information, pg_subtrans doesn't
>> isn't set for the overflowed xids, because that information is not
>> included in the WAL record. If you're lucky, the information is there
>> already, but we don't generally guarantee pg_subtrans to survive crash
>> or restart.
>
> That is exactly the reason why we don't treat an overflowed snapshot as
> a valid starting point.
We don't? I don't see anything stopping it.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com