Re: odd problem !

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>
Cc: Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: odd problem !
Date: 2005-03-22 23:11:10
Message-ID: 20455.1111533070@sss.pgh.pa.us
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Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> writes:
>> What PG version is this exactly?

> REL8_0_STABLE, I believe. I posted another problem, now "cut and pasted".

I've been able to duplicate this here. What is happening is that the
damage to ./t1 is being done when you start the postmaster in ./t2.
It looks to me like the fundamental problem is that the t2 postmaster
is replaying the WAL-logged CREATE DATABASE command from t1's xlog, and
*that log entry contains an absolute path name*. So the CREATE replay
is wiping out t1's "test" database subdirectory.

This isn't a problem in normal use of course, but it'd be a serious
issue for someone engaging in WAL-shipping, if their backup postmaster
were living at a different absolute path. We probably need to think
about whether we can make CREATE DATABASE log only relative paths.

Log-shipping CREATE TABLESPACE commands is even more interesting :-(.
Not sure how to deal with that.

regards, tom lane

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