Re: Hot Standby dev build (v8) - Mailing list pgsql-hackers

Simon Riggs wrote:
> On Fri, 2009-01-16 at 16:33 +0200, Heikki Linnakangas wrote:
>> I don't think RecentGlobalXmin is good enough here:
>>
>>> !             /*
>>> !              * We would like to set an accurate latestRemovedXid, but there
>>> !              * is no easy way of obtaining a useful value. So we use the
>>> !              * probably far too conservative value of RecentGlobalXmin instead.
>>> !              */
>>> !             xlrec_delete.latestRemovedXid = RecentGlobalXmin;
>>> !             rdata[0].data = (char *) &xlrec_delete;
>>> !             rdata[0].len = SizeOfBtreeDelete;
>> RecentGlobalXmin is just a hint, it lags behind the real oldest xmin 
>> that GetOldestXmin() would return. If another backend has a more recent 
>> RecentGlobalXmin value, and has killed more recent tuples on the page, 
>> the latestRemovedXid written here is too old.
> 
> What do you think we should do instead?

Dunno. Maybe call GetOldestXmin().

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com