Re: Set transaction waiting mode and timeout

On Wed, May 18, 2011 at 3:01 AM, Durumdara <durumdara(at)gmail(dot)com> wrote:
> Hi!
>
> In Firebird the transaction can be parameterizable as:
>
> SET TRANSACTION
>   ...
>   [WAIT | NO WAIT]
>   [LOCK TIMEOUT seconds]
>
> The "NO WAIT" is force transaction to return instantly with errormsg
> when some deadlock situation happened, Timeout is define the seconds
> for wait.
> This can be set for each transaction I used.
>
> I search for same option in pg if exists.
> Because when I do this (theid field is primary key):
>
> Con1.Begin
> Con2.Begin
> Con1.Exec(insert into x (theid, value) values (1, 'a'));
> Con2.Exec(insert into x (theid, value) values (1, 'a'));
> ...
> then Con2 is remaining in deadlock state (nothing happened, the code
> is waiting for the transaction's end).

That is not a deadlock state. A deadlock state is where con2 is
waiting on con1 AND con1 is waiting on con2.

> When Con1's transaction is end, Con2 is continue...

Then it's not deadlocked. It's just locked.

> But users better like the ErrorMessage than incomprehensible "freezed screen".
> And I also better like the controllable situation (I can re-try 3 times, etc.).

You can do a select ... for update nowait, that might get you what you want.