Data segment compression [Oracle]

Data segment compression allows to compress

• tables
• partitioned tables (some or all partitions)
• materialized views
• index organized tables
• indexes (but not bitmap indexes)
• partitioned indexes

Data compression can also be specified for a tablespace. In this case, the default for the above mentioned objects within the tablespace will be to use compression.

Table compression can only be achieved if there are duplicate values within the same db block. That is, it will be most beneficial if there is a lot of repeated values.

Objects in the sys schema cannot be compressed.