Re: Problems with listen / notify

On 06/18/2014 08:13 AM, Rafael Martinez Guerrero wrote:
> On 06/18/2014 04:33 PM, Karsten Hilbert wrote:
>> On Wed, Jun 18, 2014 at 04:14:46PM +0200, Rafael Martinez wrote:
>>
>>> When executing multiple notifies in a server *without* problems, a
>>> python script gets all notifies defined in a period of time in one
>>> poll() call (as expected)
>>>
>>> But when running the same code against a server *with* problems, the
>>> python script gets only one notify per poll() call.
>>
>> What constitutes a server "with" or "without" problems ?
>>
>> I seem to remember that notify does not guarantuee to deliver
>> each of successive identical notifications.
>>
>
> Hello
>
> I don't care about the order in which the script receives notifications.
> My problem is that I have a particular postgreSQL server that sends only
> one notification per poll() call.
>
> A have a program that checks for new notifications from a database one
> time every minute. In a "normal" server the program gets all the
> notifications generated by the database during the last minute, in the
> server with "problems" it gets only one every minute even if many
> notifications has been generated during the last minute.
>
> During a minute the database can generate several hundreds
> notifications, if the program connects to the server with "problems", it
> can take several hours to process all the notifications, while when it
> is connected to a normal server it takes a few seconds.
>
> I am just trying to understand why this server behaves in this way when
> it is not overloaded at all.

Well you still have not said what the differences between the 'normal'
and 'problem' servers are.

Some questions to start:

1) What are the Postgres versions of the servers?

2) Where are the different servers located, remote or local?

3) Are the notifications the same?
If they are what are they?
If not how do they differ?

>
> Thanks for your help.
>
> regards,
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com