Comments in-line
--
Jonathan Lewis
Yet another Oracle-related web site: http://www.jlcomp.demon.co.uk
Practical Oracle 8i: Building Efficient Databases
Publishers: Addison-Wesley
Reviews at: http://www.jlcomp.demon.co.uk/book_rev.html
John wrote in message <8bc78dd8.0105280541.4c2b8b56_at_posting.google.com>...
>
>OK
>so chained rows are not logged?
>
Yes, they are logged, but again the structure
of the logfile content probably does not lend itself
to the simple reverse engineering that 'ordinary'
updates allow.
>> You would be hard pushed to demonstrate
>> that the three operations were a single partitioned
>> row update.
>>
>
>I believe it is possible using the SCN cause they will have the same.
>But it's hard and time-consuming.
Which is probably why it is not done in this
release of log-miner. Future releases are supposed
to be much cleverer, e.g. converting:
delete from tab$ where obj# = 12345
into
drop table FRED;
>> alter system dump logfile '{fully qualified log file name}';
>>
>
>is this file explained in the oracle documentation?
>
No - you hvae to figure it all out by trial and error
for the type of data you are interested in. A couple
of key points:
a) You get two log items per data change, the
rollback of the change, and the change
b) As transactions start you get information about
rollback segment header changes adding to the volume
c) When a change is the first change to a block for a
transaction, it tends to introduce logging information
about data block header (specificially ITL) changes.
d) Even when nothing else appears to be going on in
the system, you get timeouts occuring which throw
little surprise changes into the log to confuse the issue.
Received on Thu May 31 2001 - 03:54:39 CDT
