2 Replies Latest reply: Nov 2, 2012 3:12 AM by Chrisjenkins-Oracle RSS

    A dumb question: How to use column compression on cache group tables?

    948372
      Hi teachers,

      I need to set up an asynchronous writethrough global cache group, and have it bound with an oracle table.

      Since there are huge records I want to load into this cache group, take the memory into account, I want to use columnar compression.

      Learn from some materials, I get to know that, if I want to compress those columns, the table the belongs to must be declared as "optimized for read" when creating.

      I refer to the TimesTen SQL Reference, for the CREATE CACHE GROPU section, I didn't find how to "optimized for read" when creating a cache group.

      Of course, if I create a new table in TimesTen, then I can declare this table as "optimized for read", for example:

      create table emp (id number not null) OPTIMIZED FOR READ;
      And then:
      alter table emp add (val_1 varchar2(129), val_2 varchar2(12) ) compress (val_1 BY DICTIONARY MAXVALUES = 255, val_2 BY DICTIONARY MAXVALUES = 255);

      Both of them work well.


      So, my question is: if I want to compress the columns in a cache group table, how to do?

      Looking forward to your great advices!! Thanks!!