Re: Notice lock waits

On Fri, Sep 30, 2016 at 3:00 AM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:

> On Wed, Sep 28, 2016 at 11:57 PM, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com
> > wrote:
>>
>>
>> Providing the details of lock wait to the client is good. I fell this
>> message
>> is useful for the cases where User/administrator is trying to perform some
>> SQL operations.
>>
>> I also feel that, adding a GUC variable for these logs to show it to user
>> may not be good. Changing the existing GUC may be better.
>>
>
> I don't think it would be a good idea to refactor the existing GUC
> (log_lock_waits) to accomplish this.
>
> There would have to be four states, log only, notice only, both log and
> notice, and neither. But non-superusers can't be allowed to change the
> log flag, only the notice flag. It is probably possible to implement that,
> but it seems complicated both to implement, and to explain/document. I
> think that adding another GUC is better than greatly complicating an
> existing one.
>

Yes, I understood. Changing the existing GUC will make it complex.

What do you think of Jim Nasby's idea of making a settable level, rather
> just on or off?
>

I am not clearly understood, how the settable level works here? Based on
log_min_messages
or something, the behavior differs?

The Notification messages are good, If we are going to add this facility
only for lock waits, then
a simple GUC is enough. If we are going to enhance the same for other
messages, then I prefer
something like log_statement GUC to take some input from user and those
messages will be
sent to the user.

Regards,
Hari Babu
Fujitsu Australia