Re: fragmentation issues

"Noons" <wizofoz2k_at_yahoo.com.au.nospam> wrote in message news:40b845ac$0$8986$afc38c87_at_news.optusnet.com.au...
> Dave allegedly said,on 29/05/2004 5:57 PM:
>
> > "yls177" <yls177_at_hotmail.com> wrote in message
> > news:c06e4d68.0405281858.778abb5f_at_posting.google.com...
> >
> >>1) using locally managed tablespaces with uniform extent sizes means
> >>that it is physically impossible to have fragmentation.
>
> Aye! Is this a myth-in-forming or what? LMT does NOT "make it impossible
> to have fragmentation". It just makes fragmentation unimportant. But
it's
> still possible to have portions of your objects all over the tablespace in
> multiple "chunks" (previously called "extents"). That was the "classic"
> definition of "fragmentation".

It's not a myth in the forming, I think, but it is slack use of a definition, I agree. I always try to use the phrase "tablespace fragmentation" and leave "fragmentation" to the Windows hard drive.

It has never been an issue if a segment's extents are all over the place 'inside' a tablespace. (You might go back a few versions earlier than me, so maybe I should never say never). The issue is also known by some as the 'contiguity of extents' problem. Something you can never (!) achieve physically on a file system however hard you try.

I'm slightly concerned at your use of the phrase "previously called extents". Last time I looked, they still were. DBA_CHUNKS anyone?

Regards
HJR Received on Sat May 29 2004 - 03:16:54 CDT