Sybase Adaptive Server IQ 12.4.2, Administration And Performance Manual

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CHAPTER 12 Managing System Resources
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Figure 12-1: Buffer caches in relation to physical memory
The following sections describe each part in more detail and provide guidelines
to help you determine how much memory each part requires.
Operating system and other applications
This amount will vary for different platforms and how the system is used. For
example, UNIX “cooked” file systems do more file buffering than UNIX raw
partitions, so the operating system has a higher memory requirement. As a
minimum, you can assume that UNIX systems use 60MB or more, while
Windows NT systems use 30MB or more.
In addition, other applications that run in conjunction with Adaptive Server IQ
(such as query tools) have their own memory needs. See your application and
operating system documentation for information on their memory
requirements.
Adaptive Server IQ memory overhead
After determining how much physical memory the operating system, and other
applications use, you can calculate how much of the remaining memory
Adaptive Server IQ requires to do its tasks. The factors that affect this overhead
are described in the following sections.