PostgreSQL JDBC - Re: Statement.cancel() race condition

Author

Re: Statement.cancel() race condition

Kris Jurka

2005-12-01, 8:24 pm

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/pgsq...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.

Kris Jurka

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Kris Jurka

2005-12-02, 3:24 am

On Thu, 1 Dec 2005, Kris Jurka wrote:

> On Thu, 1 Dec 2005, Kevin Grittner wrote:
>
>
> I think taking the ReceiveEOF portion of this patch:
>
> http://archives.postgresql.org/pgsq...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

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