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Why Transport Tablespace Export Dumpfile Is Larger For Datapump Export (EXPDP) Than Traditional Export (EXP) (Doc ID 605053.1)

Last updated on APRIL 03, 2020

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 10.1 to 11.1]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.


During TTS export you find that the size of the DataPump (expdp) dump file is much larger than that of same export via traditional exp. This seems strange as only metadata is being exported and DataPump by default compresses metadata. (From 10.2 Utilities guide page 2-8 "Parameters Available in Export's Command-Line Mode" COMPRESSION: Default: METADATA_ONLY)

exp \"<username/pwd>\" transport_tablespace=y tablespaces=<tablespace name(s)> file=<expfile name>.dmp tts_full_check=y log=<file name>.log
expdp \<username/pwd>\" transport_tablespaces=<tablespace name(s)> dumpfile=<expdpfile name>.dmp transport_full_check=y logfile=<file name>.log

ls -l <file name>*.dmp

-rw-r--r-- 1 grdbms grdbms 158720 Jun 20 13:56 <expfile name>.dmp
-rw-r----- 1 grdbms grdbms 503808 Jun 20 14:17 <expdpfile name>.dmp

On top of that, if you do a tablespace level export of same data where data is contained in dump file along w/ metadata you find that the DataPump dump file is then smaller than exp dump file.

exp system/pwd tablespaces=<tablespace name(s)> file=<expfile name>.dmp log=<expfile name>.log
expdp system/pwd tablespaces=<tablespace name(s)> dumpfile=<expdpfile name>.dmp log=<expdpfile name>.log

ls -l <tablespace>*.dmp

-rw-r--r-- 1 grdbms grdbms 488587264 Jun 20 15:14 <expfile name>.dmp
-rw-r----- 1 grdbms grdbms 185679872 Jun 20 16:15 <expdpfile name>.dmp


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