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 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 supported cache size, whichever is lower. The maximum
supported 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 64-bit database servers, the cache size can be considered unlimited
On Windows Mobile, the cache size is limited by available physical memory
If you use p, the argument is a percentage. You can use % as an alternative to p, but not on Windows operating systems unless you escape
the % character. To set the initial cache size to 50 percent of the physical system memory, run the following command:
dbsrv16 -ch 50%% ...
If you specify a cache size smaller than 64 MB with -ch, the database server adjusts the maximum cache to 64 MB. Specifying
a maximum cache size that is smaller than 64 MB is not recommended, but it can be done by using the -chx option.