Re: Statement.cancel() race condition

On Thu, 1 Dec 2005, Kris Jurka wrote:

> On Thu, 1 Dec 2005, Kevin Grittner wrote:
>
>>
>> The problem is that even after the exception comes out of this code, is
>> caught, and the transaction is rolled back -- we are still often able to
>> start another statement which is running by the time the server gets
>> around to interrupting the related back end process.  Obviously, having
>> the cancel of one statement actually interrupt the processing of a
>> subsequent statement violates the popular principle of "least surprising
>> result".
>>
>
> I think taking the ReceiveEOF portion of this patch:
>
> http://archives.postgresql.org/pgsql-jdbc/2003-09/msg00175.php
>
> would fix this in the single thread case.  The multi-threaded case is
> obviously more complicated.  I don't recall why the original patch wasn't
> committed.
>

I've applied this fix for single threaded applications to 8.0, 8.1 and
HEAD.  The multi-threaded stuff is more complicated than I'd like to get
into at the moment.

Kris Jurka