This chapter has focused on some of the types of I/O that I think are most useful in the real world and that aren’t well covered elsewhere. But what about these other types of I/O?
Database pipes, queues, and alerts
Oracle’s built-in web server
The DBMS_PIPE built-in package was originally designed as an efficient means of sending small bits of data between separate Oracle database sessions. With the introduction of autonomous transactions, database pipes are no longer needed if they are simply being used to isolate transactions from each other. Database pipes can also be used to manually parallelize operations.
Database queuing is a way to pass messages asynchronously among Oracle sessions. There are many variations on queuing: single versus multiple producers, single versus multiple consumers, limited-life messages, priorities, and more. The latest incarnation of Oracle’s queuing features is covered in the Oracle manual called Oracle Streams Advanced Queuing User’s Guide.
The DBMS_ALERT package allows synchronous notification to multiple sessions that various database events have occurred. My impression is that this feature is rarely used today; Oracle provides other products that fill a similar need but with more features.
You can read more about pipes and alerts in the chapter Intersession Communication in Oracle Built-in Packages (O’Reilly). For your convenience, that chapter is posted on this book’s ...