Re: Replication server timeout patch

On 11.02.2011 22:11, Robert Haas wrote:
> On Fri, Feb 11, 2011 at 2:02 PM, Daniel Farina<drfarina@acm.org>  wrote:
>> I split this out of the synchronous replication patch for independent
>> review. I'm dashing out the door, so I haven't put it on the CF yet or
>> anything, but I just wanted to get it out there...I'll be around in
>> Not Too Long to finish any other details.
>
> This looks like a useful and separately committable change.

Hmm, so this patch implements a watchdog, where the master disconnects 
the standby if the heartbeat from the standby stops for more than 
'replication_[server]_timeout' seconds. The standby sends the heartbeat 
every wal_receiver_status_interval seconds.

It would be nice if the master and standby could negotiate those 
settings. As the patch stands, it's easy to have a pathological 
configuration where replication_server_timeout < 
wal_receiver_status_interval, so that the master repeatedly disconnects 
the standby because it doesn't reply in time. Maybe the standby should 
report how often it's going to send a heartbeat, and master should wait 
for that long + some safety margin. Or maybe the master should tell the 
standby how often it should send the heartbeat?

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