SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

HP NonStop SQL/MX Installation and Management Guide—523723-004
6-1
6
Reviewing and Setting System
Defaults
NonStop SQL/MX uses system-defined default settings for attributes associated with
compiling and executing queries. The system-defined default settings, which are
hard-coded settings, are optimal in most cases. Under some circumstances, however,
you might want to override a specific system-defined default setting. System-defined
default settings can be overridden on a system level (affecting all applications) by
inserting a row into the SYSTEM_DEFAULTS table, or in a specific, limited context by
executing any of these statements:
•
CONTROL QUERY DEFAULT
•
CONTROL TABLE
•
SET TABLE
This section identifies the system defaults that are new for NonStop SQL/MX Release
2.1 and Release 2.0 and the set of system defaults that you should consider changing
after you install Release 2.1 or Release 2.0 and before you run your applications.
Sometimes a setting other than the default is recommended, but the default itself is not
changed to ensure backward-compatibility with existing applications.
This section addresses these topics:
•
Setting and Updating System Defaults on page 6-1
•
Consequences of Inserting Rows Into the SYSTEM_DEFAULTS Table on
page 6-2
•
New System Defaults for Release 2.0 on page 6-3
•
New System Default for Release 2.1 on page 6-6
•
Default Settings to Review After Installing NonStop SQL/MX on page 6-7
For comprehensive information about system defaults and the SYSTEM_DEFAULTS
metadata table, see the SQL/MX Reference Manual.
Setting and Updating System Defaults
The SYSTEM_DEFAULTS table is defined in schema SYSTEM_DEFAULTS_SCHEMA
of catalog NONSTOP_SQLMX_nodename. The SYSTEM_DEFAULTS table contains
only one row, inserted by the InstallSqlmx script for the NATIONAL_CHARSET
default, until you insert additional rows that contain default settings. To update the
SYSTEM_DEFAULTS table, you must be the super ID or a user to whom the super ID
has granted UPDATE privileges. All other users have SELECT privileges on this table.