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Overview of memory use
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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
-iqsmem is 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,
-iqwmem always provides wired memory. You cannot
specify
-iqsmem on this platform.
• On HP, AIX, and Tru64,
-iqsmem and -iqwmem provide 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
The start_asiq startup utility sets -iqsmem to a platform-specific value
automatically. On Tru64 (Digital UNIX) systems,
start_asiq does not set
-iqsmem automatically, 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.
Impact of other
applications and
databases
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 -mb to see the actual number of
segments.