To: gry@ll.mit.edu
Cc: pgsql-sql@postgresql.org
Subject: Re: debugging query to put message in pg logfile? 
In-reply-to: <20040304153219.210f3648.gry@ll.mit.edu> 
References: <20040304153219.210f3648.gry@ll.mit.edu>
Comments: In-reply-to george young <gry@ll.mit.edu>
	message dated "Thu, 04 Mar 2004 15:32:19 -0500"
Date: Thu, 04 Mar 2004 16:35:01 -0500
Message-ID: <28982.1078436101@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

george young <gry@ll.mit.edu> writes:
> I've started putting debugging queries like:
>    select "opwin.py: committing step signoff"
> in my app, just to have an entry in the postgres logfile.

> Is there some cheaper (or more appropriate) sql statement that will show
> up in the postgres log?

You could just send SQL comments:

	-- opwin.py: committing step signoff

One advantage of this is that you can merge the comments with actual
commands, thus not incurring even a network round-trip time for them.
If you do send it separately, it will act like an empty query string.

People tend not to think of this because psql strips -- comments before
sending commands.  But I believe all the lower-level libraries will pass
them through.  (If you need to pass loggable comments through psql, I
think the /* ... */ form will work.)

			regards, tom lane