On 03/12/10 01:05 PM, Masood Mortazavi wrote:Hi Masood,
I am wondering about any limitations regarding the number of Derby instances that can be embedded in a JVM ... (assuming adjustments to heap-size, etc., have been made) ...
I haven't tried this myself, but I've heard people talking about having about 1000 instances in the same JVM and getting them to run reasonably well.
The main issues were inefficient use of the heap for caching data (since each instance has its own page cache) so that each instance would have to run with a very small page cache to prevent exhausting the heap, and a high number of background threads (this problem is logged as DERBY-4210).
Others who have actually tried this might want to add to this or correct me if I've got this wrong, though...
Hope this helps,