On all 64-bit platforms, the total amount of usable memory is limited only by the virtual memory of the system. On 32-bit platforms, some restrictions apply.
On 32-bit platforms see the following table.
Platform |
Total memory available |
|---|---|
RedHat Linux 2.1 |
About 1.7GB available to Sybase IQ |
RedHat Linux 3.0 |
About 2.7GB available to Sybase IQ |
Windows 2000/2003/XPa |
2.75GB available to Sybase IQ |
aYou need Windows 2000 Advanced Server or Datacenter Server, Windows Server 2003 Standard, Enterprise or Datacenter Edition, or Windows XP Professional to get this much memory, and you must set the /3GB switch. Without the switch, the limit is 2GB. This amount is the total memory available to the process. Total size of buffer caches must not exceed 2GB on Windows servers, even with the /3GB setting. For details, see the Installation and Configuration Guide for Windows. |
|
Due to the virtual memory usage pattern within the Sybase IQ server, virtual memory fragmentation could cause excessive process growth on Windows platforms. To reduce the likelihood of this situation, Sybase IQ supports the use of Microsoft’s low-fragmentation heap (LFH) on Windows XP and Windows Server 2003.
On HP and Sun platforms, you can designate a specified amount of memory as wired memory. Wired memory is shared memory that is locked into physical memory. The kernel cannot page this memory out of physical memory.
Wired memory may improve Sybase IQ performance when other applications are running on the same machine at the same time. Dedicating wired memory to Sybase IQ, however, makes it unavailable to other applications on the machine.
To create a pool of wired memory on these UNIX platforms only, specify the -iqwmem command-line switch, indicating the number of MB of wired memory. (You must be user root to set -iqwmem, except on Sun.) On 64-bit platforms, the only upper limit on -iqwmem is the physical memory on the machine.
-iqwmem 10000
On Sun Solaris, -iqwmem always provides wired memory.
On HP, -iqwmem provides wired memory if you start the server as root. It provides unwired memory if you are not root when you start the server. This behavior may change in a future version.
Server memory 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, you may need to reduce the amount of memory your server requests.
You can also issue the UNIX command ipcs -mb to see the actual number of segments.