Re: Skip checkpoint on promoting from streaming replication

On 9 August 2012 10:45, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> On 22 June 2012 05:03, Kyotaro HORIGUCHI
> <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
>
>> I hope this is promising.
>
> I've reviewed this and thought about it over some time.

I've been torn between the need to remove the checkpoint for speed and
being worried about the implications of doing so.

We promote in multiple use cases. When we end a PITR, or are
performing a switchover, it doesn't really matter how long the
shutdown checkpoint takes, so I'm inclined to leave it there in those
cases. For failover, we need fast promotion.

So my thinking is to make pg_ctl promote -m fast
be the way to initiate a fast failover that skips the shutdown checkpoint.

That way all existing applications work the same as before, while new
users that explicitly choose to do so will gain from the new option.

--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services