Re: Transactions

On Tue, 5 Dec 2000, Mike Castle wrote:

> On Tue, Dec 05, 2000 at 04:25:20PM +0100, Helge Bahmann wrote:
> > You will still experience data loss if you do not use a journalling
> > filesystem; get the ext3 patches or try reiserfs.
>
> I believe this statement is wrong.
>
> fsync should force all data to disk. Period. Regardless of using ext2,
> ext3, or reiserfs.
yes, if fsync completes, the data is on disk; but if you hard-reset the
system (as indicated in the original mail) while fsync is in progress you
will likely end up with a garbled filesystem

>
> ext3/reiserfs *may* gain some benefit if running with -F, but even then,
> I believe both still only journal meta-data, not the data itself, so you
> could still have data stuck in cache if you don't use fsync.
correct

>
> mrc
>

BTW: Has anyone tried using O_SYNC instead of fsync in postgres? It ought
to be faster, but I wonder if anyone has some hard data on the difference.

Helge
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