Sybase 12.4.2 manual 436

Overview of memory use

Unwired memory pool On AIX, Tru64 (Digital UNIX), and HP UNIX systems, you can create an unwired (swappable) memory pool to increase total available memory. Unwired memory can be paged. To create the unwired memory pool, use the - iqsmem command-line switch. Specify this switch as the number of MB of unwired memory. The maximum value for -iqsmemis platform-specific. For example, to add 1GB of unwired memory you specify:

-iqsmem 1000

Note For this version, on some platforms there is no difference between wired and unwired memory:

•On Sun Solaris, -iqwmemalways provides wired memory. You cannot specify -iqsmemon this platform.

•On HP, AIX, and Tru64, -iqsmemand -iqwmemprovide wired memory if you start the server as root. They provide unwired memory if you are not root when you start the server. This behavior may change in a future version.

Settings in start_asiq

Impact of other applications and databases

The start_asiq startup utility sets -iqsmemto a platform-specific value automatically. On Tru64 (Digital UNIX) systems, start_asiq does not set -iqsmemautomatically, but the range of permissible values is up to 28,000MB. See the Adaptive Server IQ Installation and Configuration Guide for your platform for the range of permissible values.

Remember, the memory used for buffer caches comes out of a pool of memory used by all applications and databases. If you try to run multiple servers or multiple databases on the same machine at the same time, or if you have other applications running that use shared memory, you may need to make your buffer caches smaller.

You may also be unable to get all of memory you request in -iqsmem. The server log reports how much memory you actually get:

Created 1073741824 byte segement id 51205 Attached at 80000000

Created 184549376 byte segement id 6151 Attached at C3576000

You can also issue the UNIX command ipcs -mbto see the actual number of segments.

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