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. Like any RDBMS software, Sybase IQ requires a lot of memory. 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. See the section “Platform-specific memory options” on page 526 for information on configuring memory to minimize swapping.
To make the maximum use of your physical memory, Sybase IQ uses buffer caches for all reads and writes to your databases.
Your swap space on disk must
be at least large enough to accommodate all of your physical memory.
