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Idle workers in IMPDP with parallel option

876123Sep 30 2011 — edited Oct 12 2011
Hello gurus,

I took a datapump export of a 29GB partitioned table with the following parameters and was extremely fast (< 10 minutes):

parallel=4
filesize=500MB
directory=PUMP_DIR
estimate=statistics
dumpfile=exp%U.dmp
reuse_dumpfiles=y
logfile=export.log
tables=user1.t1

The export produced 4 parallel workers which were active the whole time, hence why the large speed.

However when I tried to take a datapump import on the same database on an empty table (different schema), the performance was very poor (55 minutes):

parallel=4
directory=PUMP_DIR
dumpfile=exp%U.dmp
logfile=import.log
tables=user1.t1
remap_schema=user1:user2
table_exists_action=append

I noticed that the parallel workers were idle all the time (irrelevant of the parallelism degree I used) and the whole import was serialized.

Can someone give me some insight why the parallel workers were idle during the IMPDP?


[r00tb0x|http://www.r00tb0x.com]
This post has been answered by Dean Gagne-Oracle on Oct 11 2011
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Locked on Nov 9 2011
Added on Sep 30 2011
#database-key-features, #export-import-sql-loader-external-tables
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