Re: Improvements for statement cancellation

On 4/10/2013 6:47 PM, Pawel Veselov wrote:
> pgpool-II has a special code that sleeps for one second before
> releasing cancel request (rather, between sending cancel requests to
> all backends involved in a connection). It has its reasons for doing
> that sleep.

there may be reasons, but anything that relies on an arbitrary timeout
like 1 second is, IMHO, poorly designed.

>
> This leaves me with a neraly-locked up system sometimes, as the
> cancellation process can take a very long time (these seconds do add
> up). Below is a sample stack trace of how it looks like, code path-wise.
>
> I'm wondering if it's possible if Postgres JDBC could change the
> implementation of cancel() so that cancelQuery() is only sent if the
> statement being called is the actual statement that is being executed
> on the connection, and otherwise be a no-op.

why use pgpool then?   use weblogic's native java connection queuing.



--
john r pierce                                      37N 122W
somewhere on the middle of the left coast