FastSort Manual

Sorting From NonStop SQL/MP
FastSort Manual—429834-003
8-2
Configuring Your SQL/MP Sort Environment

An external FastSort process (SORTPROG), if the SQL optimizer estimates that
the data to sort might exceed 4 MB, or there are fewer than 32,768 rows or fewer
than 63 columns

A sort performed by a series of inserts into a temporary key-sequenced table, if
both of the following conditions apply:

The table contains more than 500 rows and more than 63 columns

The total key length is less than 255 bytes
Configuring Your SQL/MP Sort Environment
Depending on the SQL operation you perform, you can configure your FastSort
environment for SQL/MP in three ways:

Using the =_SORT_DEFAULTS DEFINE

Using a configuration file for a parallel index load

Using LOAD command options
Setting Up a =_SORT_DEFAULTS DEFINE
The =_SORT_DEFAULTS DEFINE is the DEFINE you use to configure sorts from
SQL/MP. While configuration file and LOAD options only affect loading data, the
=_SORT_DEFAULTS DEFINE affects all SQL operations that invoke FastSort. If you
do not specify a configuration file or LOAD command options, SQL/MP uses values in
your =_SORT_DEFAULTS DEFINE for the load operation.
Note. If the total key length is greater than 255 bytes SORTPROG returns an error.
Note. Before you can use a =SORT_DEFAULTS DEFINE, you must enable DEFINEs for your
TACL session. To enable DEFINEs, execute the SET DEFMODE ON command from either
your TACL or SQLCI prompt. For more information about this command, see Section 7, Using
SORT and SUBSORT DEFINEs.