COM & .NET Component Services

Application Pooling and Recycling

COM+ 1.5 provides two new application lifecycle management options: application pooling and recycling. Both options are configurable on a new tab on the application’s properties page. Pooling and recycling services are available only for a server application. You cannot configure library applications to use pooling and recycling because they do not own their hosting process. Library applications have, in effect, the pooling and recycling parameters of whatever server application happens to load them.

Application pooling

Application pooling allows you to configure how many surrogate processes are launched to host your server application’s components. Under COM+ 1.0, all instances of components from a server application always share the same hosting process. Although this sharing is also the classic COM default, classic COM local server developers had the option of allocating a process per object (by registering the class factories with the REGCLS_SINGLEUSE flag). COM+ 1.5 gives you explicit control over how many processes are launched by configuring a processes pool. The application properties page now contains the Pooling & Recycling tab (see Figure B-9). You can configure the pool size in the Pool size edit box. The default pool size is one—a single process hosts all instances of components from the application, like in COM+ 1.0. However, if you set it to a value greater than one, COM+ 1.5 creates a process per each new instance until it reaches ...