Re: [HACKERS] Performance while loading data and indexing

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Neil Conway <neilc@samurai.com>
Cc: Bruce Momjian <pgman@candle.pha.pa.us>, shridhar_daithankar@persistent.co.in, pgsql-hackers@postgresql.org, pgsql-general@postgresql.org
Date: 2002-09-26T21:32:01Z
Lists: pgsql-hackers, pgsql-performance, pgsql-general
Neil Conway <neilc@samurai.com> writes:
> I'm not really familiar with the reasoning behind ext2's reputation as
> recovering poorly from crashes; if we fsync a WAL record to disk
> before we lose power, can't we recover reliably, even with ext2?

Up to a point.  We do assume that the filesystem won't lose checkpointed
(sync'd) writes to data files.  To the extent that the filesystem is
vulnerable to corruption of its own metadata for a file (indirect blocks
or whatever ext2 uses), that's not a completely safe assumption.

We'd be happiest with a filesystem that journals its own metadata and
not the user data in the file(s).  I dunno if there are any.

Hmm, maybe this is why Oracle likes doing their own filesystem on a raw
device...

			regards, tom lane