Running vendor library functions in fenced-mode processes

Db2 vendor library functions, vendor utilities, and routines used to be run inside agent processes. In Db2 9.5 and later, because the Db2® database manager itself is a multithreaded application, vendor library functions that are no longer threadsafe and cause memory or stack corruption or, worse, data corruption in Db2 databases. For these reasons, a new fenced-mode process is created for each invocation of a vendor utility, and vendor library functions or routines run inside this fenced-mode process. This does not result in significant performance degradation.