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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 AUGUST 04, 2018

Applies to:

Oracle Server - Enterprise Edition - Version: 10.1.0.2 to 11.1.0.6 - Release: 10.1 to 11.1
Information in this document applies to any platform.

Goal

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 \"/ as sysdba\" transport_tablespace=y tablespaces=TOOLS,TC,USERS file=TTS_exp.dmp tts_full_check=y log=TTS_exp.log
expdp \"/ as sysdba\" transport_tablespaces=TOOL,TC,USERS dumpfile=TTS_expdp.dmp transport_full_check=y logfile=TTS_expdp.log

ls -l TTS*.dmp

-rw-r--r-- 1 grdbms grdbms 158720 Jun 20 13:56 TTS_exp.dmp
-rw-r----- 1 grdbms grdbms 503808 Jun 20 14:17 TTS_expdp.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/manager tablespaces=TOOLS,TC,USERS file=tablesp_exp.dmp log=tablesp_exp.log
expdp system/manager tablespaces=TOOLS,TC,USERS dumpfile=tablesp_expdp.dmp log=tablesp_expdp.log

ls -l tablesp*.dmp

-rw-r--r-- 1 grdbms grdbms 488587264 Jun 20 15:14 tablesp_exp.dmp
-rw-r----- 1 grdbms grdbms 185679872 Jun 20 16:15 tablesp_expdp.dmp

Solution

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