Use Oracle DUL to recover truncated partition on 11g/10g

The truncate command does two things. It will grab a new data_object_id (or dobj#). And unless you explicitly specify “reuse storage”, the extent map for that segment will be mostly if not entirely cleared out/reformatted.

If that’s the case, then you may have to give DUL the datafile block offsets to dump from. Someone with more actual experience with DUL (I personally have practically none) might know how to leverage a hopefully very recent backup to get the partition’s “pretruncate” extent map and/or previous data_object_id.

There’s also a DUL Help Forum in Beehive but I don’t see a question related to “truncate” there:

http://www.parnassusdata.com/en/node/270

We meet some problems while doing DUL.

I did some tests on my laptop , seems it’s easy to recover a dropped table by using DUL (with data_object_id

not change, and the dropped table can be found in SEG.dat), but for truncated table, we only see the new

data_object_id in SEG.dat and once scan the blocks it report

“Analyzing segment: data object id 51355 segment header at ( file 4 block 67)

DUL: Warning: Segment skipped, no extents in scanned extent map”

So we want to confirm with you, does DUL support recovery truncated object with data_object_id changed ?

or how can we force DUL to scan all the blocks whatever the segment header block tell ?