Paging Increases Available Memory

Although paging increases the amount of available memory, avoid or minimize page swapping for good memory management.

When there is not enough memory on your system, performance can degrade severely. If this is the case, you need to find a way to make more memory available. The more memory you can allocate to Sybase IQ, the better.

However, there is always a fixed limit to the amount of memory in a system, so sometimes operating systems can have only part of the data in memory and the rest on disk. When the operating system must go out to disk and retrieve any data before a memory request can be satisfied, it is called paging or swapping. The primary objective of good memory management is to avoid or minimize paging or swapping.

The most frequently used operating system files are swap files. When memory is exhausted, the operating system swaps pages of memory to disk to make room for new data. When the pages that were swapped are called again, other pages are swapped, and the required memory pages are brought back. This is very time-consuming for users with high disk usage rates. In general, try to organize memory to avoid swapping and, thus, to minimize use of operating system files.

To make the maximum use of your physical memory, Sybase IQ uses buffer caches for all reads and writes to your databases.

Note:

Your swap space on disk must be at least large enough to accommodate all of your physical memory.

Related concepts
Utilities to Monitor Swapping
Server Memory
Manage Buffer Caches
Determine the Sizes of the Buffer Caches
Set the Buffer Cache Sizes
Specify the Page Size
Optimize for Large Numbers of Users
Platform-Specific Memory Options