3.3.5 Restoring an Exadata Hybrid Columnar Compression Table

The compressed table backup can be restored to a system that supports Exadata Hybrid Columnar Compression, or to a system that does not support Exadata Hybrid Columnar Compression.

• When restoring a table with Exadata Hybrid Columnar Compression to a system that supports Exadata Hybrid Columnar Compression, restore the file using Oracle Recovery Manager (RMAN).

• When an Exadata Hybrid Columnar Compression table is restored to a system that does not support Exadata Hybrid Columnar Compression, you must convert the table from Exadata Hybrid Columnar Compression to an uncompressed format.

Use the following steps to convert an Exadata Hybrid Columnar Compression table to an uncompressed format.

1. Ensure that there is sufficient space to store the data in uncompressed format.
2. Use RMAN to restore the Exadata Hybrid Columnar Compression tablespace.
3. Alter the table compression from Exadata Hybrid Columnar Compression to NOCOMPRESS:

   For example:

   SQL> ALTER TABLE table_name MOVE ONLINE NOCOMPRESS;

   Alternatively, you can use the following command to move the data in parallel:

   SQL> ALTER TABLE table_name MOVE ONLINE NOCOMPRESS PARALLEL;

   If the table partitioned, then alter the compression method for each partition separately. For example:

   SQL> ALTER TABLE table_name MOVE PARTITION partition_name NOCOMPRESS ONLINE;

After you convert the table to an uncompressed format, you can optionally use another form of compression, such as OLTP compression or Oracle Database In-Memory compression.