Interpret change_vector$$ column

[Jr]

Hello,

How would i interpret Change_Vector$$ Column
of MLOG$_ log table on Master Table ?

Update TAB1 Set COL1='xyz' ;

The above update statement will poulate the Logtable
with following values

COLUMN
UPDATED VALUE
---- -----
Col1 02
col2 04
col3 08
col4 10

col5 20
col6 40
col7 80
col8 0001

Thanks
Jr.

[Axr2]

Please do your home works before posting here. Metalink is a decent resource for such information.

"The column is a bit vector that indicates which columns in the master table were changed by a DML statement."

[Jr]

I understand, what change_Vector$$ column stores,
but i need to decode the value so that i can rebuild the DML statement.
Thanks
Jr.

[Axr2]

For starters, what are you trying to? Trying to do a materialized view fast refresh? Do you understand how it works and what a snapshot log holds? Why do you care about this column? What DML?

[Jr]

Can anyone else Know how to decode?

[Jr]

Originally posted by Axr2
For starters, what are you trying to? Trying to do a materialized view fast refresh? Do you understand how it works and what a snapshot log holds? Why do you care about this column? What DML?

What are you trying to do -
Cloned 850GB DB, and now trying to propogate the DMLs from the CLoned DB to Prod DB.
Trying to do a Materialized view Fast Refresh? -
- Kindof , cause, the trigger machanism to log into the Logtable is kernalized and it would be faster to UserDefinedTrigger.
Do You understand how it works -
Well, I dont know Oracle internals but i do know how documented stuff works.
Why do you care about this column ?
This column will help me to update only the afftected columns.
Lets say, it has value '02' then i will update only the firstcolumn with new value for that RowID.
What DML ?
Based on DMLTYPE$$ Column valu , i will build the DML Statement.

Got any answer for me now ?

GoodLuck!!!

[tamilselvan]

You can do nothing. The change_vector$$ is internal to oracle.

Tamil

[Axr2]

Originally posted by Jr
Can anyone else Know how to decode?

At this point, I assumed you didn't want my inputs and never bothered to see your next post.

In any case, it should be fairly apparent by now that you can't do jack with that column. Looks like you are trying to rebuild the wheel..and are trying to rewrite Oracle's replication using triggers or whatever. Good luck with that. Good luck with finding documentation about internals.

Might be better if you state what you are trying to accomplish (bigger picture) and someone might be able to suggest an alternate solution.

Got any answer for me now ?

See above.

GoodLuck!!!

It is you that needs it.

[reydp]

Originally posted by Jr

Got any answer for me now ?

GoodLuck!!!

Honesty, I am pretty impress by your motivation of doing your stuff.
But haven't you thought of any other approach of doing what you want to accomplish?

Why riding a boat(without a compass) of reaching to an island where in you can use helicopter to get there?

Anyway, if I'll be in your shoes, I could just probably clone the db like doing a standby db, apply all logs to the standby db. And after all logs are applied, open the standby db and do those replication(materialized views,dblinks,etc.) and as long as you have correctly created this replications, Oracle will just automatically update those DMLs from PRODDB to CLONEDB or vice versa for you.

regards,
rey