This option limits the size of the database server cache during automatic cache growth. By default the upper limit is approximately
the lower of the maximum non-AWE cache size and 90% of the total physical memory of the computer.
The size is the amount of memory, in bytes. Use k, m, or g to specify units of kilobytes, megabytes, or gigabytes, respectively.
The unit p is a percentage either of the physical system memory, or of the maximum non-AWE cache size, whichever is lower. The maximum
non-AWE cache size depends on the operating system. For example:
2.5 GB for Windows 32-bit Advanced Server, Enterprise Server and Datacenter Server
3.5 GB for the 32-bit database server running on Windows x64 Edition
1.5 GB on all other 32-bit Windows operating systems
On Windows Mobile, the cache size is limited by available physical memory
On 64-bit database servers, the cache size can be considered unlimited
If you use p, the argument is a percentage. You can use % as an alternative to p, but on Windows operating systems, which use % as an environment variable escape character, you must escape the % character.
To set the initial cache size to 50 percent of the physical system memory, you would run the following command:
On 64-bit operating systems, -ch and -chx are equivalent, but -ch is recommended.