oracle logmnr 報錯"In Memory Undo is unsupported"

非原創 

Logminer Gives Error - In Memory Undo is unsupported!

Why logiminer Gives error?

We see that structure of redo entries is different, for IMU logminer can’t recover full picture of transaction in same time.

Now see on metalink, note ID 428167.1 which give us solution for avoid error “In Memory Undo is unsupported” in future!

1.Logminer cannot always populate all the fields of the v$logmnr_contents this is
because the redo may/may not have all the information that we need for every
column. Adding Supplemental Logging will help in more info being logged in the
redo being generated, helping populate more values. This can be done by the
following commands:
SQL> ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY,
UNIQUE INDEX) COLUMNS;
SQL> ALTER SYSTEM SWITCH LOGFILE;
Additionally, it is not unusual for 10g to generate more redo than previously
seen in earlier versions.

2: Logminer cannot always populate all the fields of the v$logmnr_contents this is because the redo
may/may not have all the information that we need for every column, you need to enable supplemental
logging on the database following
Supplemental logging is required to receive reliable and consistent information from logminer.
Without supplemental logging enabled, the redo may not contain enough information
for LogMiner to construct the correct sql_redo (or any sql_redo in the case of in-memory undo, IMU).
LogMiner does not work with IMU and turning supplemental logging on disables IMU.
Please enable supplemental logging as per to eliminate these messages and update
whether you still encounter the UNSUPPORTED messages.

3: Logminer may not be able to find sql_redo for transactions that were created before supplemental
logging is enabled.
It will only work for redo's which contains information to extract the correct sql_redo