Re: is sync rep stalled?

On 04.10.2010 10:49, Markus Wanner wrote:
> On 10/04/2010 09:18 AM, Heikki Linnakangas wrote:
>> With 'replay' and hot standby combination, you'll want to set
>> max_standby_archive_delay to a very low value, or a read-only query can
>> cause master to stop processing commits (or the standby to stop
>> accepting new queries, if that's preferred).
>
> Well, given that DML-only transactions aren't prone such to conflicts, I
> think of this as a corner case.

Yes they are. Any DML operation, and even read-only queries IIRC, can 
trigger HOT pruning, which can conflict with a read-only query in a hot 
standby. And then there's autovacuum which can cause conflicts in the 
standby, even if no user transactions are running in the master.

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