From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
cc: Andres Freund <andres@anarazel.de>,
        pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Unified logging system for command-line programs
In-reply-to: <a7c07b9c-8aa4-f9bb-e9eb-30111b732645@2ndquadrant.com>
References: <6a609b43-4f57-7348-6480-bd022f924310@2ndquadrant.com>
 <21141.1546199123@sss.pgh.pa.us>
 <20181231155557.7mokxwg7fnvoxd4a@alap3.anarazel.de>
 <841dd9fb-3550-dce0-e9ff-8f64cac9f15d@2ndquadrant.com>
 <20190103180315.o4gh3id5quh5aebc@alap3.anarazel.de>
 <a7c07b9c-8aa4-f9bb-e9eb-30111b732645@2ndquadrant.com>
Comments: In-reply-to Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
	message dated "Thu, 03 Jan 2019 19:54:28 +0100"
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Date: Thu, 03 Jan 2019 16:01:14 -0500
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Peter Eisentraut <peter.eisentraut@2ndquadrant.com> writes:
> On 03/01/2019 19:03, Andres Freund wrote:
>>> Relatedly, rewriting all the frontend programs to exception style would
>>> end up being a 10x project to rewrite everything for no particular
>>> benefit.  Going from 8 or so APIs to 2 is already an improvement, I
>>> think.  If someone wants to try going further, it can be considered, but
>>> it would be an entirely different project.

>> Why would it be 10x the effort,

> Because you would have to rewrite all the programs to handle elog(ERROR)
> jumping somewhere else.

FWIW, this argument has nothing to do with what I was actually
proposing.  I envisioned that we'd have a wrapper in which
non-error ereports() map directly onto what you're calling
pg_log_debug, pg_log_warning, etc, while ereport(ERROR) has the
effect of writing a message and then calling exit(1).  We would
use ereport(ERROR) in exactly the places where we're now writing
a message and calling exit(1).  No change at all in program
flow control, but an opportunity to consolidate code in places
that are currently doing this sort of thing:

#ifndef FRONTEND
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not open file \"%s\" for reading: %m",
                        ControlFilePath)));
#else
    {
        fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
                progname, ControlFilePath, strerror(errno));
        exit(EXIT_FAILURE);
    }
#endif

			regards, tom lane