Compressed Primary Keys

You'll need to be careful when using compressed indexes for primary keys until you have applied patchset 9202. Consider the following example

SQL> create table T ( x, y, z)
  2  as select 1,2,3 from dual;

Table created.

SQL> create index T_IX on T (x,y);

Index created.

SQL> alter  table T add constraint C primary key (x,y);

Table altered.

SQL> alter  index T_IX rebuild compress 1;

Index altered.

(so far so good...)

SQL> insert into t values (1,2,3);

ERROR at line 1:
ORA-08102: index key not found, obj# 69517, dba 29368266