Re: Cancelling Requests Frontend/Backend Protocol TCP/IP

On 02/11/2009, at 20:01, John DeSoi wrote:

>
> On Nov 2, 2009, at 12:17 PM, Raimon Fernandez wrote:
>
>> when postgres has finished processing the select, just before
>> sending the first row(1), in the middle(2), or at the end(3), when
>> the last row has been sent ?
>>
>> If I send the CancelRequest when postgres is in point 3, I'm too
>> late, but if postgres is in 1 or 2, the CancelRequest will have
>> some effect.
>>
>> I'm still wrong here ?
>>
>> thanks for clarification the concept!
>
> Yes, it will have some effect in cases 1 and 2. You will know it
> worked because you'll get error 57014 - canceling statement due to
> user request.
>
> An easy way to test this out is to call pg_sleep with a big number
> and then cancel the query on another connection. You won't have to
> worry about the timing of receiving all rows or not.

thanks!

Now I can Cancel them using the Front End or the pg_cancel_backend, I
had an error in my FrontEnd function, no is working ...

:-)

thanks for all,

regards,

raimon