Re: IMP/EXP accross platforms: What will be missing?

From: Rick Denoire <100.17706_at_germanynet.de>
Date: Thu, 06 Nov 2003 00:38:32 +0100
Message-ID: <bguiqvskfrlkoped89cumg4d8pd1ac7riv@4ax.com>

"Howard J. Rogers" <hjr_at_dizwell.com> wrote:

>> If importing serially, extents will be allocated so that they will be
>> physikally contiguous on the harddisk.
>
>You can't say that. Extents end up wherever the file system you use deems it
>appropriate to put them. Even the blocks of an extent can't be guaranteed to
>be contiguous one with another.

OK. But I would expect that the probability of blocks an extents being written contiguous is higher when only those blocks and extents are being written.

>Myth alert!!

:-)

>The idea that extents should be contiguous on disk is exactly what
>underpinned Oracle's own recommendation in about version 5 to try and get
>all segments in one extent... and we've been suffering from that nonsense
>ever since (Compress=Y in exports, anyone??). It was never true then, and it
>isn't true now.

Somehow I feel proud to share this misconception with Oracle... (until now).

Thanks
Rick Denoire Received on Wed Nov 05 2003 - 17:38:32 CST