Run on a single-processor computer
If you are running the database server on a single-processor computer, set the MULTIPROCESSOR configuration parameter to 0. To run the database server with only one CPU virtual processor, set the SINGLE_CPU_VP parameter to 1.
Setting MULTIPROCESSOR to 0 enables the database server to bypass the locking that is required for multiple processes on a multiprocessor computer. For information about the MULTIPROCESSOR configuration parameter, see the HCL Informix® Administrator's Reference.
Setting
SINGLE_CPU_VP to 1 allows the database server to
bypass some of the mutex calls that it normally makes when it runs
multiple CPU virtual processors. For information about setting the
SINGLE_CPU_VP parameter, see the HCL
Informix Administrator's Reference.
Important: Setting VPCLASS num to 1 and
SINGLE_CPU_VP to 0 does not reduce the number of
mutex calls, even though the database server starts only one CPU virtual
processor. You must set SINGLE_CPU_VP to 1 to reduce
the amount of latching that is performed when you run a single CPU
virtual processor.
Setting the SINGLE_CPU_VP parameter
to 1 imposes two important restrictions on the database
server, as follows:
- Only one CPU virtual processor is allowed.
You cannot add CPU virtual processors while the database server is in online mode.
- No user-defined classes are allowed. (However, users can still define routines that run directly on the CPU VP.)
For more information, see Add virtual processors in online mode.