Env:
CPU: 24 Physical CPU = 48 logical CPU
------------------------------------------------------------
Test 1 (includes all info):
Table file size (only one table): 700M
expdp parallel=5; just only generated 2 dump files.
impdp parallel=1; elapsed time is 00:04:36
impdp parallel=2; elapsed time is 00:03:55
impdp parallel=5; elapsed time is 00:04:56
impdp parallel=48; elapsed time is 00:05:17
Conclusion: parallel=2
------------------------------------------------------------
Test 2 (includes table data only):
Table file size (the whole db): 12G
impdp parallel=5; elapsed time is 00:21:00
impdp parallel=48; elapsed time is 00:14:00
impdp parallel=96; elapsed time is 00:14:00
Conclusion: if parallel > 2x CPU, then no any help.
------------------------------------------------------------
PARALLEL = 16 = CPU processors.
1. DBMS_STATS.GATHER_SCHEMA_STATS
DEGREE=>16
Tue Apr 1 20:15:57 HKT 2014
Tue Apr 1 20:20:04 HKT 2014
4 min 7 sec
DEGREE=>7
Tue Apr 1 20:24:50 HKT 2014
Tue Apr 1 20:29:12 HKT 2014
4 min 22 sec
DEGREE=>1 (Default)
Tue Apr 1 20:34:26 HKT 2014
Tue Apr 1 20:57:42 HKT 2014
23 min 16 sec
2. impdp
PARALLEL=7
Apr 1 16:35:34 2014
Apr 1 16:51:37 2014
16 min 3 sec
PARALLEL=16
Apr 1 21:06:21 2014
Apr 1 21:22:20 2014
15 min 59 sec