Now i want to dump the UNDO record entry which contains the transactionn details ..
How do i map it with the segment_name .. I mean segment_name contains block_id and v$transaction contains UBABlk address ..
And how can i dump it ?
I mentioned ALTER SYSTEM DUMP undo block RBS_NAME xid XIDUSN, XIDSLOT, XIDSQN;
means you are going to dump directly of undo datafile and said block, you are saying alter system dump undo block (i am going to dump undo block); while;
If you says : allter system dump datafile <number datafile> block <<block number>>; means you are going to dump any datafile's block with datafile number and block. So, the difference is ...dump undo block and ...dump datafile. As far as technical differences, i have'nt gone till now to see the exact difference, but i think there will no change in the trace file as such, because at last you wish to see the dump of block.
Dumping of undo is divided into following topics:
(A) Undo Header
(B) Undo Segment
(B) Undo Block
I am sorry if it sounds like a stupid question ... But i am new to this area ...
Just one thing , UNDO tablespace also finally resides in the datafiles right ?
And when i give the file number of undotablespace file in alter system dump datafile << file number >> ,
it will dump undo file contents , isn't it ?
Atleast that gave me the undo contents as output , when i tried !!
If you are going to dump the datafile, you are going to see the file's contents. What you need to dump is the transaction table and segment header of Undo. The datafile contents would just have the undo records. You may also want to peek into x$ktuxe and x$ktcxb tables.