Advanced Queuing - Oracle

Restrictions on Queue Management
Collection Types in Message Payloads
You cannot construct a message payload using a VARRAY that is not itself
contained within an object. You also cannot currently use a NESTED Table even as
an embedded object within a message payload. However, you can create an object
type that contains one or more VARRAYs, and create a queue table that is founded
on this object type.
For example, the following operations are allowed:
CREATE TYPE number_varray AS VARRAY(32) OF NUMBER;
CREATE TYPE embedded_varray AS OBJECT (col1 number_varray);
EXECUTE DBMS_AQADM.CREATE_QUEUE_TABLE(
queue_table => 'QT',
queue_payload_type => 'embedded_varray');
Synonyms on Queue Tables and Queues
All AQ PL/SQL calls do not resolve synonyms on queues and queue tables.
Although you can create a synonyms, you should not apply the synonym to the AQ
interface.
Tablespace Point-in-Time Recovery
Nonpersistent Queues
Note: Queue names and queue table names are converted to
upper case. Mixed case (upper and lower case together) is not
supported for queue names and queue table names.
AQ currently does not support tablespace point-in-time recovery. Creating a queue
table in a tablespace will disable that particular tablespace for point-in-time
recovery.
Currently you can create nonpersistent queues of RAW and ADT type.You are limited
to sending messages only to subscribers and explicitly specified recipients who are
local. Propagation is not supported from nonpersistent queues. When retrieving
messages, you cannot use the dequeue call, but must instead employ the
asynchronous notification mechanism, registering for the notification by mean of
LNOCISubcriptionRegister.
4-10 Oracle9i Application Developer’s Guide - Advanced Queuing