Compression in Datapump of Oracle 11g

June 25, 2012 | By

Compression feature of Oracle 11g Datapump

The ability to constrict the meta-data associated with a Information Push job was first provided in Oracle Data source 10g Launch 2. In Oracle Data source 11g, this pressure capability has been extended so that desk data can be compacted on trade.

Data Pump compression is an in sequence process, so the decreased dump file size denotes an important savings in disk space. Dissimilar operating system or file system compression methods, Data Pump compression is entirely in order on the import side as well, so there is no require to uncompress a dump file before importing it. The compressed dump file sets are robotically decompressed throughout import devoid of any extra steps by the Database Administrator.

Full Information Push performance is available using a compacted data file. Any control that is used on a regular data file will also work on a compacted data file. Users have the following options to determine which parts of a dispose of information file set should be compressed:

ALL enables pressure for the whole trade function.

DATA-ONLY outcomes in all data being published to the dispose of information file in compacted structure.

METADATA-ONLY outcomes in all meta-data being published to the dispose of information file in compacted structure. This is the standard.

NONE immobilizes compression for the whole export process.

The decrease in dump file size will differ based on data types and other things. Note that when importing using Data Pump, the CREATE TABLE statements will have compression clauses that match the explanation in the export file. If a compression clause is missing, then the table comes into the COMPRESSION characteristics of the tablespace where the table is stored.

In Oracle Database 11g, Oracle provides the mechanism to compress both data and metadata during the extract operation. The available options for the COMPRESSION parameter are as follows:

compression={all | data_only | metadata_only | none}

Following is an example:

$expdp full=yes userid=”‘/ as sysdba'”  dumpfile=dbadir:full.compress.dmp compression=all

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