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Sunday, February 11, 2007

Oracle Database Windows/UNIX Differences

Automatic Startup and Shutdown
On UNIX
several files and scripts in different directories are used to start an instance automatically. Other scripts are run on computer shutdown, allowing applications such as Oracle Database to shut down cleanly.

on Windows
set registry parameter ORA_SID_AUTOSTART to true
To start the listener automatically, set services startup type to automatic

Background Processing and Batch Jobs
UNIX provides sophisticated control mechanisms for background processing and batch jobs
Windows, use the AT command or a GUI version in the Microsoft Resource Kit

Diagnostic and Tuning Utilities
On UNIX
utilities such as sar and vmstat are used to monitor Oracle Database background and shadow processes

on Windows
Oracle Counters for Windows Performance Monitor, Task Manager, Control Panel, Event Viewer, User Manager, and Microsoft Management Console (included only with Windows 2000).

Task Manager on Windows displays currently running processes and their resource usage, similar to the UNIX ps -ef command or HP OpenVMS SHOW SYSTEM. But Task Manager is easier to interpret and the columns can be customized

Dynamic Link Libraries (DLLs)
Shared libraries on UNIX are similar to shared DLLs on Windows. Object files and archive libraries are linked to generate Oracle Database executables. Relinking is necessary after certain operations, such as installation of a patch.

On Windows, Oracle Database DLLs form part of the executable at run time and are therefore smaller. DLLs can be shared between multiple executables. Relinking by the user is not supported, but executable images can be modified using ORASTACK.


Initialization Parameters: Multiple Database Writers
On UNIX, you can specify more than one database writer process with initialization parameter DB_WRITERS. Multiple database writers can help, for example, when a UNIX port does not support asynchronous I/O.

DB_WRITERS is supported but typically unnecessary on Windows, which has its own asynchronous I/O capabilities.

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