In the course of investigating a Liferay platform issue, you may be instructed by Liferay Support to export your database schema in Oracle. The following article contains guidelines for this export.
Resolution
1. Use Oracle Data Pump (EXPDP) for creating the export file.
With the advent of Oracle Data Pump (EXPDP/IMPDP) in 10g you have a newer, faster and more flexible alternative at hand to the traditional EXP and IMP utilities.
2. Take a consistent dump by specifying the current SCN.
While your dump is being created by EXPDP there might be transactions which are changing your data in the background as well. This circumstance might lead to undesirable results when we import your data at our end.
The old export utility (EXP) had a CONSISTENT=Y option that ensured the data consistency of the dump. For Oracle Data Pump there is no CONSISTENT parameter. With EXPDP, the same functionality is achieved with the FLASHBACK_SCN and FLASHBACK_TIME parameters.
Refer to the following link for more.
3. Compress the export file.
In order to conserve disk space, please compress the dump file before uploading. If you are using Oracle 11gR1 or later, you can use EXPDP's built-in mechanism for compressing. As an alternative, traditional OS utilities like ZIP/GZIP/etc. can be used.
Refer to the following link for more.
4. Upload the log file - generated by EXPDP - as well.
In order to facilitate the investigation of your issue, please upload the log of EXPDP along with the dump.
Additional Information
Let's see an example how to produce a database dump taking the guidelines above into account.
1. Query the current SCN from the database.
SQL> SELECT CURRENT_SCN FROM v$database;
CURRENT_SCN
-----------
2627102
2. Create a file with the following content, and please customize DUMPFILE, DIRECTORY, LOGFILE and the SCHEMAS options to match your environment.
cat support_export.par COMPRESSION=ALL DUMPFILE=lportal.dmp DIRECTORY=DATA_PUMP_DIR LOGFILE=lportal_export.log SCHEMAS=LPORTAL_6120 REUSE_DUMPFILES=Y
3. Create the dump file by issuing the following command.
expdp system/password parfile=support_export.par flashback_scn=2627102