Compressing Tables On Import

In earlier versions, Data Pump always performed an import operation using the same compression settings that were present during the export process.

Data Pump is now enhanced to allow you to specify a compression method at import time regardless of the compression method used when the data was exported, or if you prefer, you can also now decompress tables during an import.

This new feature is now possible due to the introduction of a new metadata TRANSFORM parameter called TABLE_COMPRESSION_CLAUSE. If set to NONE, the table compression clause is ignored and it will be imported using the default compression mode for the tablespace, or you can use any valid table compression clause available such as: NOCOMPRESS, COMPRESS BASIC, COMPRESS FOR OLTP, COMPRESS FOR QUERY, or COMPRESS FOR ARCHIVE.

Note: If the table compression clause has more than one word, then you must use single or double quotation marks.

Here you can see an example of using compression on import:

$ impdp test/test DIRECTORY=datapump DUMPFILE=test.dmp TRANSFORM=TABLE_COMPRESSION_CLAUSE:'COMPRESS FOR OLTP'