Improve DBWR Throughput
To improve DBWR’s throughput, consider the following:
- Disk capabilities and setup (stripe size, speed, controllers etc…)
- Using raw devices instead of File System files — depending on their efficiency on your system.
- Spreading database file across drives and controllers
- Using Async IO if supported
- If asynch IO is not possible, using multiple database writers. This is done with the DB_WRITERS database parameter in Oracle7, and the DBWR_IO_SLAVES database parameter in Oracle8 and 9.
- Using multiple DB Writer gatherer processes in Oracle8 using the DB_WRITER_PROCESSES parameter.
- Using the “Multiple buffer pools” feature in Oracle8 and Higher. See Note:135223.1 on the Oracle Metalink website.
Achieving the optimal setup for DBWR is highly dependent on the characteristics of your platform. The maximum I/O size the platform supports and the ability to support Asynchronous I/O are examples of these characteristics.