Re: Latest version of Hot Standby patch

Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>

From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Simon Riggs <simon@2ndQuadrant.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2008-12-19T11:58:30Z
Lists: pgsql-hackers
Simon Riggs wrote:
> On Fri, 2008-12-19 at 10:59 +0200, Heikki Linnakangas wrote:
>> Simon Riggs wrote:
>>> * corner case behaviour of backendids - bgwriter writes checkpoint WAL
>>> records. Has no backendid, but needs a slotid (possibly others)
>> Why does bgwriter need a slotid? It doesn't run any transactions.
>>
>>> * slotids are assigned once and never changed, so allowing them to be
>>> used as array lookups directly
>> So are backend ids.
> 
> I'm a little hazy, to be sure. I'm pretty sure there was a blocker, but
> if I cannot recall it we should assume it doesn't exist.
> 
> Where are you going with the thought? Remove slotId from each proc and
> then use backendId to identify the recovery proc?

Yep.

Well, to be honest, I don't much like the whole notion of tracking the 
slots. I think we should just rely on the XLOG_RECOVERY_END records to 
purge stale PGPROC entries, belonging to backends that died without 
writing an abort record.

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