Poor Performance With DataPump Export On Large Databases (Doc ID 473423.1)

Last updated on JULY 26, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 10.2.0.3 and later
Information in this document applies to any platform.
***Checked for relevance on 15-Jan-2016***

Symptoms

#> expdp $USERNAME/$PASSWORD directory=DATAPUMP_DIR dumpfile=$TODAY.$ORACLE_SID.dmp logfile=$TODAY.$ORACLE_SID.log full=y parallel=2

The size of dump file is approx. 92 GB.

DataPump export takes almost 24 hours. Traditional export (exp) takes 12 hours consistently.

Changes

 Check if Dictionary and Fixed Objects statistics have been gathered previously to start the DataPump job or not. The DBA_OPTSTAT_OPERATIONS view is useful in determining the time stamp of statistics modifications :

SQL> alter session set nls_date_format='dd-mon-yyyy hh24:mi';
SQL> select operation, START_TIME, END_TIME from DBA_OPTSTAT_OPERATIONS;

 Typically, if Dictionary and Fixed Objects statistics have been previously gathered, then gather_dictionary_stats and gather_fixed_objects_stats values have to be found in DBA_OPTSTAT_OPERATIONS.OPERATION column.

Cause

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