SQL/MX 2.x Reference Manual (G06.24+, H06.03+)

Metadata Tables
HP NonStop SQL/MX Reference Manual—523725-004
10-56
Query Optimization and Performance
MSCF_ET_REMOTE_MSG_
TRANSFER
The value of this default is used to factor in the cost
of transferring messages to and from a remote node.
It reflects the bandwidth of the physical
communication link. You should set it to a value
greater than the cost factor of transferring messages
to or from a local node, which is 0.000046.
Allowable values: 1.17549e-038 through
3.40282e+38.
The default value is 0.00005.
NUMBER_OF_USERS Set to the number of users that can run concurrent
queries that use large amounts of memory. For
these queries, the optimizer uses this number to limit
the amount of memory available for one user. The
larger the number, the less memory available for
operators (such as hash join) that use much
memory.
Allowable values: 1, >1.
The default setting is 1, which means that all
available memory can be assigned to one query.
OLT_QUERY_OPT Set to ON or OFF. When set to ON, NonStop
SQL/MX enables a fast path evaluation method for
certain simple SQL queries, such as a single table
unique select.
For more information about this setting, see the
SQL/MX Query Guide.
The default is ON.
OPTIMIZATION_LEVEL Set to 0, 1, 2, 3, 4, or 5 to indicate increasing effort
in optimizing SQL queries.
For more information about this setting, see the
SQL/MX Query Guide.
The default is 3.
OPTS_PUSH_DOWN_DAM Set to 1 (on) or 0 (off). When set to 1, the system
considers pushing down a plan to DAM for
compound statements or nested joins. When set to
0, the system does not consider this option. When
pushing a plan down to DAM is possible (the value
is 1), NonStop SQL/MX might not select the push-
down plan because of its cost.
For more information about this setting, see the
SQL/MX Query Guide.
The default is 0.
Attribute Setting