Update trigger in oracle on updating a column updating notebook motherboard compaq 1000
To keep the redo log file dumps as clean as possible, we need a database with no activity.
I have one such database and I have disabled all automatic jobs to make the redo dumps as clean as possible.
Notice that I am using ‘Riyaj’ as the value to update, as I can search for ASCII representation of my first name in hex easily in the dump file.
I mean, Come on, who would not know the ASCII representation of their first name in hex?
CHANGE vector #4 is modifying the block with DBA 0x00c00694 which is for the object with object_id 4294967295.
Objects with object_id close to 4GB are for undo segments. That undo record describes how to rollback the change: Update the row at slot 0 column 0 in the block with DBA 0x0100113d to ’52 69 79 61 6a’.
So, undo records are created in the undo block and these undo records describe how to rollback the SQL changes.
Redo records are generated describing the changes to those undo blocks too.
Please refer to the output below and I am showing only relevant details.
Test case #1: Updating column to the same value ============ Session #1: alter system checkpoint; alter system switch logfile; Session #2: update updtest set v1='Riyaj'; commit; Session #1: alter system switch logfile; Essentially, Last redo log file has the redo records generated by executing the update statement.
We need to dump the redo log file to see contents of the log file.
Then, We update the row with the same value from another session and commit.
From Session #1, we switch log again from session #1.