HG_DELETE_METHOD option

Specifies the algorithm used during a delete in a HG index.

0 – 3

0

DBA permissions are not required to set this option. Can be set temporary, for an individual connection, or for the PUBLIC group. Takes effect immediately.

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.