Re: point in time recovery and moving datafiles online

From: Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>
To: tgl(at)sss(dot)pgh(dot)pa(dot)us
Cc: marc(at)bloodnok(dot)com, pgsql-hackers(at)postgresql(dot)org
Subject: Re: point in time recovery and moving datafiles online
Date: 2002-03-08 01:42:19
Message-ID: 20020308104219G.t-ishii@sra.co.jp
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> Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp> writes:
> > What would happen if a table is dropped or truncated while doing tar
> > on it?
>
> Nothing bad, unless tar itself got confused. (Which could perhaps
> happen in the TRUNCATE case; I dunno if tar is happy when it can't read
> as much from the file as it originally expected.) As far as DROP goes,
> any standard Unix system will postpone the physical file delete until
> the last open file descriptor closes.

My concern is after DROP TABLE is committed. In my understanding when
the backup process starts,it records a LSN somewhere (maybe
pg_control?) to remember the place where the archive log recovery
could start later.

Consider a scenario:

(1) backup process starts (and records LSN)
(2) DROP TABLE t1 starts
(3) DROP TABLE t1 commits
(4) backup process ends

I think the database status should be able to go back to (1) using
the archive log recovery. No?
--
Tatsuo Ishii

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