Re: Latches, signals, and waiting

On Wed, Sep 15, 2010 at 11:14 PM, Heikki Linnakangas
<heikki.linnakangas@enterprisedb.com> wrote:
>> (One issue is that it's not clear what that'd translate to on Windows.)
>
> pg_ctl failover ? At the moment, the location of the trigger file is
> configurable, but if we accept a constant location like "$PGDATA/failover"
> pg_ctl could do the whole thing, create the file and send signal. pg_ctl on
> Window already knows how to send the "signal" via the named pipe signal
> emulation.

Right.

> Fujii-san suggested that we might have a user-defined function for
> triggering failover as well.

The attached patch introduces such a user-defined function. This is
useful especially when clusterware like pgpool-II is located in remote
server since it can trigger failover without using something like ssh.

> That's also handy, but it's not a replacement
> because it only works in hot standby mode.

Yep.

And we should increase the sleep time in walsender's poll loop (i.e.,
increase the default value of wal_sender_delay) too? Currently it's
very small, 200ms.

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center