Oracle 11g: Table Compression
Now, on Oracle 11g you can Compress an oracle table.
Remember that any compression is CPU intensive. It is not a good idea to
compress OLTP tables.
The following is an example of how to create a compressed table.
create table my_compressed_table (
compress for all operations;
The clause "compress for all operations" enables compression on all DML
activities like INSERT, UPDATE, etc. Notice that the compress doesn't
happen immediately. The compression algorithm will start in the block
when it is needed to minimize the performance impact on the database.