Various methods of table compression have been introduced at each release. Some require a specific storage system Some requires specific options. Some are only for static data. And it's not always very clear for the simple reason that their name has changed.
Name change for technical reasons (ROW/COLUMN STORE precision when a columnar compression has been introduced) or for marketing reason (COMPRESS FOR OLTP gave the idea that other - Exadata - compression level may not be suited for OLTP).
Of course that brings a lot of ambiguity such as:
- HCC is called 'COLUMN STORE' even if it has nothing to do with the In-Memory columns store
- COMPRESS ADVANCED is only one part of Advanced Compression Option
- EHCC (Exadata Hybrid Columnar Compression) is not only for Exadata
- COMPRESS FOR OLTP is not called like that anymore, but is still the only compression suitable for OLTP
- HCC Row-Level Locking is not for ROW STORE but for COLUMN STORE. It's suited for DML operation but is different than FOR OLTP. Anyway COLUMN STORE compression can be transformed to ROW STORE compression during updates. And that locking feature is licenced with the Advanced Compression Option, and available in Exadata only...
- When do you need ACO (Advanced Compression Option) or not?
Let's make it clear here.