Re: Hot Standby query cancellation and Streaming Replication integration

On Fri, Feb 26, 2010 at 10:21 AM, Heikki Linnakangas
<heikki.linnakangas@enterprisedb.com> wrote:
> Richard Huxton wrote:
>> Can we not wait to cancel the transaction until *any* new lock is
>> attempted though? That should protect all the single-statement
>> long-running transactions that are already underway. Aggregates etc.
>
> Hmm, that's an interesting thought. You'll still need to somehow tell
> the victim backend "you have to fail if you try to acquire any more
> locks", but a single per-backend flag in the procarray would suffice.
>
> You could also clear the flag whenever you free the last snapshot in the
> transaction (ie. between each query in read committed mode).

Wow, that seems like it would help a lot.  Although I'm not 100% sure
I follow all the details of how this works.

...Robert