Re: loss of system datafile with no cold backup

From: koert54 <k_at_k.com>
Date: Thu, 12 Jul 2001 18:21:28 GMT
Message-ID: <IUl37.4590$Xy1.792154@afrodite.telenet-ops.be>

The tool I was talking about is DUL - I've only seen it in action once at a site where Oracle had to recover vital data. Oracle is very protective about this tool and it costs a ton of money to use it.
One of the Oracle guys was so nice to give a small demo and I must say - I was very impressed (it should be for 250+$/hour)... The tool analyses all rows to determine the column datatypes, length, etc If the system tablespace (datafile) is available it can unload the datadictionary (all this when the DB
is down and corrupted) ... if you lost the datafile it'll use its own heuristic functions to create a
dictionary by scanning the remaining DB files - the downpart is that all your tablenames & column
names are gone ....
I was so impressed by this tool that I started 'designing' my own little data unloader...
The problem is that info on the datafile format is as good as non existing and I will consider it
allready a small victory if I'll be able to unload a simple table.... (hey you have to do something
for fun ???) However- information on DB blocks and the byte layout of tables can be reconstructed...

> > Also any tool truly capable of unloading datafiles will soon be
> > out of operation, due to legal circumstances: the tool will be
> > violating licenses like no one did before.
I agree ... - but what about Quests live reorg - it analyses the online redolog files and applies
changes to a copy of a table to keep it in sync ... Either they have :

1. some sort of license agreement with Oracle
2. re-engineered the Oracle redolog files
3. the Oracle source code ? (I know that the source code of Oracle 7 once

was posted
on the net .... Oracle got a bit stricter about giving access to the source code for
Oracle personel after that)
4. or - Oracle doesn't care ...

Cheers,
K

"Galen Boyer" <galenboyer_at_hotpop.com> wrote in message news:wkae2f9kku.fsf_at_msn.com...
> On Sun, 8 Jul 2001, postbus_at_sybrandb.demon.nl wrote:
>
> > I'm not sure whether such tool should exist to compensate for
> > someone's carelessnes.
>
> I don't know if someone who is handed the reigns of DBA is really
> being careless. They, both the person assigning the role and the
> person accepting the role probably had no idea what that term
> really meant until something drastic like this happens.
>
> I would blaim this mentality on MS myself. People think that
> everything should be as easily installable as those products when
> they forget that with such ease you lose lots of power of knowing
> underneath the covers.
>
> > Also any tool truly capable of unloading datafiles will soon be
> > out of operation, due to legal circumstances: the tool will be
> > violating licenses like no one did before.
>
> How is trying to get at one's data from a database that one
> bought violating any agreements?
>
> > I'm sure Larry will sue the person(s) distributing the
> > tool. Why would he give away his crown jewels?
>
> Just cause we don't use the tool that Larry's clan created? So,
> if someone has an interface better than sqlplus, are they to be
> sued as well?
>
> --
> Galen
> I don't want to be the rock. Yeah, okay, what do you want to be?
> I want to be the piece of glass.
Received on Thu Jul 12 2001 - 13:21:28 CDT