Re: Transaction Snapshots and Hot Standby

Csaba Nagy wrote:
> On Thu, 2008-09-11 at 15:23 +0300, Heikki Linnakangas wrote:
>> I'd imagine that even if applying the WAL on the slave is blocked, it's 
>> still streamed from the master to the slave, and in case of failover the 
>> slave will fast-forward before starting up as the new master.
> 
> Which begs the question: what happens with a query which is running on
> the slave in the moment when the slave switches from recovery mode and
> starts up ? Should the running queries be canceled if they are blocking
> applying of WAL, to allow start-up, or let them finish ?

Depends on application, I'd say. I guess we'll need both, like the smart 
and fast shutdown modes.

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