Re: libpq program SELECT FOR UPDATE and TIMEOUT or CANCEL REQUEST

On Mon, May 19, 2003 at 10:55:23 -0700, Jeffrey Pogodzinski <jrpogo@yahoo.com> wrote:
> Hi,
> 
> I am programming using libpq under Linux.
> 
> When I do a "select ... for update" to lock a row, how 
> would I allow user to cancel or timeout when requesting the
> the same row from another program/transaction.

You can set statement_timeout.

> I do not want the user to have to wait for the update on the 
> other end. I would rather send the user an error message
> saying that the record is LOCKED -- try again later.

It is generally bad design to hold database locks while waiting for
user input. It is generally better to keep information about updates
in a table and have the applications use this information to advise
or prevent conncurrent updates to the same data by different people.