Message-ID: <534F21E6.7080705@2ndquadrant.com>
Date: Thu, 17 Apr 2014 08:35:50 +0800
From: Craig Ringer <craig@2ndquadrant.com>
Organization: 2nd Quadrant
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To: Petr Jelinek <petr@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>,
 Andres Freund <andres@2ndquadrant.com>
CC: Tom Lane <tgl@sss.pgh.pa.us>, Antonin Houska <antonin.houska@gmail.com>,
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Subject: Re: bgworker crashed or not?
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On 04/17/2014 04:47 AM, Petr Jelinek wrote:
> 
> Well the logging is just too spammy in general when it comes to dynamic
> bgworkers but that's easy to fix in the future, no need to make
> decisions for 9.4.

Agreed - it's the *API* that we need sorted out for 9.4, and log output
isn't something Pg tends to consider part of the API.

> However I really don't like that I have to exit with exit code 1, which
> is normally used as failure, if I want to shutdown my dynamic bgworker
> once it has finished the work. And this behavior is something we can set
> properly only once...

As far as I can tell we have a couple of options:

- Redefine what the exit codes mean so that exit 0 suppresses
auto-restart and exits silently. Probably simplest.

or

- Expose a worker's BackgroundWorkerHandle as a global within the
worker, and let it TerminateBackroundWorker(my_bgw_handle) its self.


Of those, just changing the meaning of the exit code seems simpler and
easier. It's not clear to me why it appears to be contentious.

I don't think the status quo, with no way to exit a dynamic bgworker w/o
an error, is OK. It's like those delightful "Error: Success" messages
one gets when using perror() inappropriately - deeply confusing to
users. Lets try not to be stuck with that when we can avoid it.

-- 
 Craig Ringer                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services


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