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Export (exp) taking long time and reading UNDO

amardeep.sidhuJun 9 2010 — edited Jun 10 2010
Hi Guys,

Oracle 9.2.0.7 on AIX 5.3

A schema level export job is scheduled at night. Since day before yesterday it has been taking really long time. It used to finish in 8 hours or so but yesterday it took around 20 hours and was still running. The schema size to be exported is around 1 TB. (I know it is bit stupid to take such daily exports but customer requirement, you know ;) ) Today again it is still running although i scheduled it to run even earlier by 1 and 1/2 hour.

The command used is:
exp userid=abc/abc file=expabc.pipe buffer=100000 rows=y direct=y 
recordlength=65535 indexes=n triggers=n grants=y 
constraints=y statistics=none log=expabc.log owner=abc
I have monitored the session and all the time the wait event is db file sequential read. From p1 i figured out that all the datafiles it reads belong to UNDO tablespace. What surprises me is that when consistent=Y is not specified should it go to read UNDO so frequently ?

There is total of around 1800 tables in the schema; what i can see from the export log is that it exported around 60 tables and has been stuck since then. The logfile, dumpfile both has not been updated since long time.

Any hints, clues in which direction to diagnose please.

Any other information required, please let me know.

Regards,
Amardeep Sidhu
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Locked on Jul 8 2010
Added on Jun 9 2010
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