Efficiency of storing an Oracle User Defined Type in an index organized table

Question

Are there known issues with storing user defined types within index organized tables in Oracle 10G?

CREATE OR REPLACE TYPE MyList AS VARRAY(256) OF NUMBER(8,0);

CREATE TABLE myTable (
    id NUMBER(10,0) NOT NULL, 
    my_list MyList NOT NULL)
    CONSTRAINT pk_myTable_id PRIMARY KEY(id))
ORGANIZATION INDEX NOLOGGING;

With this type and table setup, I loaded via insert append ~2.4M records and it took 20G of space at which point I ran out of disk space. Looking at the size of the data types, this seemed to be taking up a lot of space for what was being stored. I then changed the table to be a regular table (not IOT) and I stored 6M+ records in ~7G of storage, added the PK index which took an additional 512M.

I've used IOT many times in the past, but not with a user defined type.

Why is it that the storage requirements when using a UDT and IOT are so high?

Answer 1

AFAICR, Oracle always stores VARRAY's out of row in the IOT's.

I'll now try to find the references in the docs to confirm this.