Modifying the onconfig file

You can modify the onconfig file for your database server to customize server function or tune server behavior.

By default, the onconfig file is in the INFORMIXDIR/etc directory. The ONCONFIG environment variable specifies the name and location of the onconfig file.

The onconfig.std file is a template configuration file from which you can copy configuration parameter settings. The onconfig.std file is a template and not a functional configuration. You can copy and rename the onconfig.std file, but do not modify or delete theonconfig.std file. If you omit a parameter value in your copy of the configuration file, the database server either uses default values in onconfig.std template file or calculates values that are based on other parameter values.

You can modify the onconfig file by any of the following methods:

  • You can use the HCL OpenAdmin Tool (OAT) for Informix® to monitor and update your configuration. OAT provides suggestions for configuration parameter values to optimize your database server configuration.
  • You can use a text editor to modify configuration parameter values. The changes take effect after the next time the database server is shut down and restarted.
  • You can modify the values of many configuration parameters dynamically without restarting the database server by running the onmode -wf to update configuration parameters permanently or by running the onmode -wm command to update configuration parameters in memory.
  • You can generate an onconfig file with settings that are optimized for the connections, disk space, and CPU usage that you estimate by running the genoncfg utility.
  • You can export, import, and modify configuration parameters in groups:
    • Use the onmode –we command to export a snapshot of the current configuration to a file. The resulting snapshot can then be archived, used as a configuration file, or imported to another running instance.
    • Use the onmode –wi command to import tunable configuration parameters from a previously exported file. Configuration parameters in the file that are not dynamically tunable are ignored.
  • You can modify, reset, export, and import a configuration file with SQL administration API commands:
    • Use modify config argument with the admin() or task() function to change the value of a configuration parameter.
    • Use the export config and import config arguments with the admin() or task() function to export or import a file that contains one or more dynamically tunable configuration parameters.
    • Use the reset config or reset config all argument with the admin() or task() function to revert the value of a configuration parameter or all configuration parameters to its value in the onconfig file.

You can compare two onconfig files by running the onconfig_diff utility.

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