Calling pl/sql api through multiple java threads

Question

Hi All,
I need to call a pl/sql api from multiple java threads simultaneously and all thread will use same db connection.
I want to know if all the threads will simultaneously call the pl/sql api then will the local variable inside pl/sql procedure be shared between them or they will get separate instances of variables.
TIA

Answer 1

You cannot make multiple parallel client calls over the same Oracle session handle. There is a single non-threaded/non-fibre serialised server process servicing client requests for that session. (physical process on Linux/Unix, thread in the oracle.exe process on Windows).
Each thread on the client side, needs its very own Oracle session. Thus each thread will have a server process footprint on the server. Which could be problematic if 10 clients each starts 10 threads - as it means a 100 processes on the server are needed to service these client threads.
Have a look at Overview of OCI Multithreaded Development in the Oracle® Call Interface Programmer's Guide for how to use the threading call interface of the OCI - as oppose to rolling your own where each thread manually needs to deal with is OCI session context.