Re: Need a debugging tip or two

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Peter Eisentraut <peter_e(at)gmx(dot)net>
Cc: "Kevin O'Gorman" <kogorman(at)pacbell(dot)net>, PGSQL Hackers List <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Need a debugging tip or two
Date: 2000-11-08 00:12:41
Message-ID: 24877.973642361@sss.pgh.pa.us
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Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
> There's probably little reason to start a backend standalone. If you want
> to do stock-of-the-trade debugging you simply start a postmaster, then
> psql (or whatever floats your boat), and attach gdb to the resulting
> backend process.

Right, that's what I always do (unless I have to debug a crash at initdb
time :-(). A tip here is that you can even debug backend-startup-time
problems this way, and no you don't have to be superhumanly quick on the
trigger: you set PGOPTIONS="-W n" in the environment of psql. This
will cause an n-second sleep() call very early in the backend startup
process. I find 30 seconds plenty of time to run ps, start gdb, and
attach. You can also throw in things like "-d2" to crank up the
postmaster log level for just the backend under test.

I thought this lore was in the developer's FAQ already, but I don't
see it there at the moment. Bruce, is it lurking someplace else?

regards, tom lane

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