HG_DELETE_METHOD Option

Allowed Values

0 – 3

Default

0

Scope

Option can be set at the database (PUBLIC) or user level. When set at the database level, the value becomes the default for any new user, but has no impact on existing users. When set at the user level, overrides the PUBLIC value for that user only. No system privilege is required to set option for self. System privilege is required to set at database level or at user level for any user other than self.

Requires the SET ANY PUBLIC OPTION system privilege to set this option. Can be set temporary for an individual connection or for the PUBLIC role. Takes effect immediately.

Remarks

This option chooses the algorithm used by the HG index during a delete operation. The cost model considers the CPU related costs as well as I/O related costs in selecting the appropriate delete algorithm. The cost model takes into account:

Rows deleted
Index size
Width of index data type
Cardinality of index data
Available temporary cache
Machine related I/O and CPU characteristics
Available CPUs and threads
Referential integrity costs

To force a “small” method, set this option to 1. To force the “large” method, set the option to 2. To force a “midsize” method, set the option to 3.