Client requirements for execution
To implement a multiplexed connection, set the multiplexing
option, in the client sqlhosts file or registry,
on the dbservername parameter of the database server to which
you will connect. To specify multiplexing, set the
m option
to 1. The following dbservername parameter
specifies a multiplexed connection to the personnel database
server: | Servername | nettype | hostname | servicename | options |
|---|---|---|---|---|
| personnel | onsoctcp | corp | prsnl_ol | m=1 |
Setting the multiplexing option to zero (m
= 0), which is the default, disables multiplexing for the
specified database server.
To use multiplexed connections for any application that was compiled before version 9.13 of Informix® ESQL/C for UNIX™ or version 9.21 of Informix ESQL/C for Windows™, you must relink it. Applications that you compiled before these versions of Informix ESQL/C can connect to a multiplexing database server, however. The database server establishes a non-multiplexed connection in this case.
On Windows platforms, in addition
to setting the multiplexing option in the sqlhosts registry
you must also define the ifx_session_mux environment variable.
If you do not define the ifx_session_mux environment variable,
the database server ignores the multiplexing option and does not multiplex
connections.
Restriction: On Windows, a multithreaded application must
not use the multiplexed-connection feature. If a multithreaded application
enables the multiplexing option in the sqlhosts registry
entry and also defines the IFX_SESSION_MUX environment
variable, it can produce disastrous results, including crashing and
data corruption.
If a multithreaded application and a
single-threaded application are running on the same Windows computer, the single-threaded application
can use a multiplexed connection in the following two ways:
- Use different sqlhosts information.
- Use a dbserver alias in the sqlhosts file
that does not specify the multiplexing option. For example, you could
use the following configuration:
Servername Nettype Host name Servicename Options personnel onsoctcp corp prsnl_01 m=1 personnel_nomux onsoctcp corp prsnl_02
Any multithreaded application connecting to the personnel server uses the servername personnel_nomux while single-threaded applications can continue to use the servername personnel.