Re: Fix for log_line_prefix and session display

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>
Cc: PostgreSQL-development <pgsql-hackers(at)postgreSQL(dot)org>
Subject: Re: Fix for log_line_prefix and session display
Date: 2012-10-16 16:38:11
Message-ID: 20121016163811.GI7494@momjian.us
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Applied.

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On Mon, Oct 15, 2012 at 02:22:33PM -0400, Bruce Momjian wrote:
> On Mon, Oct 15, 2012 at 10:01:29AM +0200, Albe Laurenz wrote:
> > Bruce Momjian wrote:
> > > Currently, our session id, displayed by log_line_prefix and CSV
> > output,
> > > is made up of the session start time epoch seconds and the process id.
> > > The problem is that the printf mask is currently %lx.%x, causing a
> > > process id less than 4096 to not display a full four hex digits after
> > > the decimal point. I think this is confusing because the number .423
> > > appears higher than .1423, though it is not. Here is what our current
> > > output looks like with log_line_prefix="%c: ":
> > >
> > > 50785b3e.7ff9: ERROR: syntax error at or near "test" at
> > character 1
> > > 50785b3e.7ff9: STATEMENT: test
> > > 50785b3e.144: ERROR: syntax error at or near "test" at
> > character 1
> > > 50785b3e.144: STATEMENT: test
> > >
> > > With my fix, here is the updated output:
> > >
> > > 507864d3.7ff2: ERROR: syntax error at or near "test" at
> > character 1
> > > 507864d3.7ff2: STATEMENT: test
> > > 507864d3.013d: ERROR: syntax error at or near "test" at
> > character 1
> > > 507864d3.013d: STATEMENT: test
> > >
> > > Patch attached.
> >
> > Do you think that anybody wants to apply a linear ordering on
> > the second part of the session ID? If you need the pid, you
> > can use %p.
> >
> > I would say that this change makes sense if it causes disturbance
> > that the part after the period can be than 4 characters long
> > (it did not disturb me when I wrote a log file parser).
> >
> > If that need is not urgent enough, maybe it would be better to
> > preserve the current behaviour in the (unlikely) event that somebody
> > relies on it.
>
> I don't think anyone is picking apart the session id, but I do think the
> current output is confusing because the session id string length is
> pretty variable. Anyone who is parsing the current session id will
> easily be able to parse the more consistent output.
>
> --
> Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
> EnterpriseDB http://enterprisedb.com
>
> + It's impossible for everything to be true. +
>
>
> --
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--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

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