Re: Hot Standby and handling max_standby_delay - Mailing list pgsql-hackers

From Dimitri Fontaine
Subject Re: Hot Standby and handling max_standby_delay
Date
Msg-id m2zl4enqnu.fsf@hi-media.com
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In response to Re: Hot Standby and handling max_standby_delay  (Simon Riggs <simon@2ndQuadrant.com>)
Responses Re: Hot Standby and handling max_standby_delay  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
Simon Riggs <simon@2ndQuadrant.com> writes:
> On Fri, 2010-01-15 at 20:50 +0200, Heikki Linnakangas wrote:
> Yes, it does. And I know you're thinking along those lines because we
> are concurrently discussing how to handle re-connection after updates.

With my State Machine proposal, we could only apply max_standby_delay if
in sync state, and cancel query unconditionally otherwise.

> The alternative is this: after being disconnected for 15 minutes we
> reconnect. For the next X minutes the standby will be almost unusable
> for queries while we catch up again.

That's it. And it could be the cause of another GUC, do we want to give
priority to catching-up to get back in sync, or to running queries. That
would affect to when we apply max_standby_delay, and when set to prefer
running queries it'd apply in any state as soon as we accept connections.

Regards,
-- 
dim


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