External optimizer directives

If you are user informix, you can create, save, and delete external directives.

  • Creating and saving external directives
    You can define external directives by creating association records that include query optimizer directives, and saving those records in the sysdirectives system catalog table. Association records associate a list of one or more optimizer directives with a specific query text. The database server can apply those optimizer directives to subsequent instances of the same query text.
  • Enabling external directives
    After you create and save external directives, you must set the configuration parameter and environmental variable that enable the directives. The database server searches for a directive for a query only if the external directives are set on both the database server and the client.
  • Deleting external directives
    When you no longer need an external directive, the DBA or user informix can use the DELETE statement of SQL to remove it from the sysdirectives system catalog table.
Parent topic: Optimizer directives
Related concepts:
What optimizer directives are
Reasons to use optimizer directives
Preparation for using directives
Guidelines for using directives
Types of optimizer directives that are supported in SQL statements
Configuration parameters and environment variables for optimizer directives
Optimizer directives and SPL routines
Avoiding index or prepared object exceptions by forced reoptimization
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