Process Configuration File

The database server uses configuration parameters to allocate shared-memory segments during initialization and restart. If you modify a shared-memory configuration parameter, you must shut down and restart the database server for the change to take effect.

The ONCONFIG, onconfig, and onconfig.std files are stored in $INFORMIXDIR/etc on UNIX and %INFORMIXDIR%\etc on Windows. During initialization, the database server looks for configuration values in the following files, in this order:

1. If the ONCONFIG environment variable is set, the database server reads values from the ONCONFIG file.

   If the ONCONFIG environment variable is set, but the database server cannot access the specified file, it returns an error message.

2. If the ONCONFIG environment variable is not set, the database server reads the configuration values from the ONCONFIG file.
3. If you omit a configuration parameter in your onconfig file, the database server reads the configuration values from the $INFORMIXDIR/etc/onconfig.std file.

You should always set the ONCONFIG environment variable before you initialize or restart the database server. The default configuration files are intended as templates and not as functional configurations. However, the server will not initialize if onconfig_std is missing. For more information about the configuration file, see Configuring the Database Server.

The restart process compares the values in the current configuration file with the previous values, if any, that are stored in the root dbspace reserved page, PAGE_CONFIG. When differences exist, the database server uses the values from the current ONCONFIG configuration file when the database server is restarted.