Re: What is fragmentation in databases ?

In message <E9HwGH.7LE_at_ddvictor.dundee.NCR.COM>

        smp <> writes:

> >==========Atif Ahmad Khan, 26/04/97==========
> >
> >
> >I was flipping through the pages of the latest Oracle magazine
> >and saw an ad that offered a product to address the fragmentation
> >problem in database servers by ARIS (DFRAG 5.0- Page 37). I am
> >not sure what fragmentation in databases is and what this product
> >does. Does anybody know ? Just curious.
> >
> >Atif Khan
> >aak2_at_ra.msstate.edu
> >
> Hi,
> We use ARIS DFRAG for our Oracle Financials database. It is a tool
> which can be used to report on fragmentation, numbers of extents,
 chaining of
> indexes etc.
> It can be run GUI, from forms 3 or in character mode on the server.
> It will give a graphical report of exactly where in datafiles the table
> segments are.
> It can be used to coalesce free space (we run oracle 7.1.3), to
 rebuild tables
> (and
> associated indexes) online (ie while the users are logged in) or offline, it
> can be
> running while you aren't there - (no more weekends at work)and, best of all
> from
> my point of view, it will rebuild complete tablespaces, without the pain of
> export
> and import. It tells you what is happening as it does it and it is pretty
> robust. I've
> had dealings with the company directly as to use the product we had to get
> them
> to port it to our flavour of Unix and they were very helpful. They are based
> in Seattle
> and we are in Scotland but the time difference didn't make any difference to
> them.
> The product isn't too expensive either.
> (no I don't work for them I'm just happy to have a tool that works!)
 

> Sally Pearce
> Financials DBA(for my sins)

Also, fragmentation is the 'breaking up' of the tablespace through further allocation of free space to allow for growth of tables and indexes. When allocation takes place the next area of free space that is big enough is allocated to allow for the next extent to be allocated. This leads to lots of little areas of free space that are useless to you dotted around your tablespaces. Not only this they will normally be positioned in such a way as to artifically reduce the amount of free space in the tablespaces.

ps sally, can I have some more details about this product please? Received on Wed May 14 1997 - 00:00:00 CDT