>Hi all;
>I am developing COM servers using Strahl's ideas, using FOXISAPI.
>I have one running smoothly. Can anyone tell me some criteria to assign a value to the FOXISAPI.INI parameter: 'maximum instances of server'? How daoes it impact on perfomance?
>TIA
It could well be that you are better off with only one instance - this is a particularly complex matter!
Let's say that you have two types of process. One of which takes much longer to execute than the other. Allowing requests for these processes to be queued to a single instance of your server does not make sense. Because while one slow request is being dealt with, it is possible that many quick requests could also have been dealt with concurrently.
On the other hand, if all of your processes take about the same amount of time. Then you may find that multiple instances will result in CPU cycles being wasted as the OS switches between the various threads (I think this is referred to as
context switching) as the two processes
dual for the processor.
Also, the number of CPU's is a factor - though there is no guarantee that two instances of your server running on a two-processor motherboard will actually be allocated one to each processor.
Another factor is whether or not you are using VFP6 Service Pack 3. This allows multi-threaded DLL's (or EXE's) to be built (i.e. COM objects). I'm guessing that this allows multiple copies of your COM server to be instantiated by FOXISAPI.DLL - but only one copy of your DLL or EXE needs to be loaded into memory. I know that with early versions of FOXISAPI if you set the number of instances to three, and your COM Server was out-of-process (i.e. an EXE), then once all three instances had been instantiated, then you would also be able to see three instances of the EXE in memory (using the Process Tab of the NT4 Task Manager). I've not tested the multi-threaded Servers that can be built with SP3 to see if this is still the case.
Houston.
censored.
