Freeing statement-level access paths

You can remove catalog table rows that are used to influence access path selection. Doing so enables Db2 to optimize the access path for the statements, and reclaims disk space that is used to store the catalog table rows.

Before you begin

The following prerequisites are met:

• You have one of the following authorities:
  • SQLADM
  • SYSADM
  • SYSCTRL
  • SYSOPR

Important: Catalog table rows that enforce access path reuse are also removed for specified statements. When the statements are next prepared, Db2 generates new access paths for any such statements.

To free access paths:

Issue a FREE QUERY command, and specify one of the options that are shown in the following table:

Option	Description
To delete all existing rows	Specify the QUERYID(ALL) option.
To delete only rows for a particular query	Specify QUERYID(queryID), where queryID matches the value of the QUERYID column of the catalog tables.
To delete all rows for a group of related queries.	Specify FILTER(value), where value is the value of the FILTER column of the USERFILTER column in the SYSIBM.SYSQUERY catalog table.