Optimizing Servlet Performance
5-6 Oracle HTTP Server powered by Apache Performance Guide
ApJServHost JServ2 ajpv12://127.0.0.1:8002
ApJServRoute JS1 JServ1
ApJServRoute JS2 JServ2
ApJServShmFile /usr/local/apache/logs/jserv_shm
*The ApJServMount directive, with /servlets
balance://set/root, now balances requests for servlets in /servlets
between JServ1 and JServ2.
*The ApJServBalance directive identifies JServ1 and JServ2 as the
processes that share the load. The ’2’ following JServ2 is a weight value.
It specifies that twice as many requests will be sent to JServ2 as would
be otherwise, i.e., that JServ2 will get about 2/3 of all incoming
requests. See "Distribution of JServ Requests" below for details.
*The ApJServHost directive identifies the host and port on which the
processes are listening.
*The ApJServRoute directive associates JServ processes with sessions.
JServ uses this information to keep all of a session’s requests together in
one process. The JServ session mechanism sends the process route
information back to the user (generally in a cookie). You need only
modify it if your application uses sessions.
*The ApJServShmFile directive specifies a shared memory file that the
httpd processes may use to track the state of the JServ processes.
Distribution of JServ Requests
mod_jserv selects the JServ engine to handle a request using the process outlined
below:
1. An httpd process is started.
2. mod_jserv creates a list of available JServs, with extra entries for JServs with a
weight value greater than 1 (for example, JServ2 in our example above, as
specified by ApJServBalance set JServ2 2).
3. An httpd daemon receives a servlet request and hands it to mod_jserv.
4. mod_jserv selects the JServ engine that will handle the request.
a. mod_jserv checks to see if the request is part of a current session. If so, it
uses the ApJServRoute directives to find the JServ that handled the other
requests for that session.