Oracle9i Application Developer's Guide - Advanced Queuing Release 1 (9.0.1) Part Number A88890-02 |
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Managing AQ, 4 of 10
When a queue table is exported, the queue table data and anonymous blocks of PL/SQL code are written to the export dump file. When a queue table is imported, the import utility executes these PL/SQL anonymous blocks to write the metadata to the data dictionary.
The export of queues entails the export of the underlying queue tables and related dictionary tables. Export of queues can only be done at queue-table granularity.
A queue table that supports multiple recipients is associated with the following tables:
These tables are exported automatically during full database mode and user mode exports, but not during table mode export. See "Export Modes".
Because the metadata tables contain rowids of some rows in the queue table, the import process will generate a note about the rowids being obsoleted when importing the metadata tables. This message can be ignored, since the queuing system will automatically correct the obsolete rowids as a part of the import operation. However, if another problem is encountered while doing the import (such as running out of rollback segment space), you should correct the problem and repeat the import.
Exporting operates in full database mode, user mode, and table mode, as follows. Incremental exports on queue tables are not supported.
MCQ
, you must also export the following tables:
AQ$_<queue_table>_I (the dequeue IOT) AQ$_<queue_table>_T (the time-management IOT) AQ$_<queue_table>_S (the subscriber table) AQ$_<queue_table>_H (the history IOT)
Similar to exporting queues, importing queues entails importing the underlying queue tables and related dictionary data. After the queue table data is imported, the import utility executes the PL/SQL anonymous blocks in the dump file to write the metadata to the data dictionary.
A queue table that supports multiple recipients is associated with the following tables:
These tables must be imported as well as the queue table itself.
You should not import queue data into a queue table that already contains data. The IGNORE
parameter of the import utility should always be set to NO
when importing queue tables. If the IGNORE
parameter is set to YES
, and the queue table that already exists is compatible with the table definition in the dump file, then the rows will be loaded from the dump file into the existing table. At the same time, the old queue table definition and the old queue definition will be dropped and recreated. Hence, queue table and queue definitions prior to the import will be lost, and duplicate rows will appear in the queue table.
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