SQL/MX 2.x Reference Manual (H06.10+, J06.03+)

Metadata Tables
HP NonStop SQL/MX Reference Manual—544517-008
10-60
Query Optimization and Performance
INFER_CHARSET Set to infer the character set information of the
character constants from the metadata of the
corresponding column for any data manipulation
operations. The values are:
OFF = do not infer (default)
ON = do infer
When the INFER_CHARSET is turned ON, do not
specify the charset from the INSERT, SELECT,
UPDATE, and DELETE statements for SQL/MX or
SQL/MP tables in the MXCI and from embedded
programs and stored procedures.
JOIN_ORDER_BY_USER Enables (ON) or disables (OFF) the join order
specified you specify in the FROM clause of a query.
When set to ON, the optimizer considers only
execution plans that have the join order you specify.
For additional information about this setting, see the
SQL/MX Query Guide.
The default is OFF.
MAX_ESPS_PER_CPU_PER_OP Set to the maximum number of ESPs the optimizer
considers starting for each CPU for a given operator.
For additional information about this setting, see the
SQL/MX Query Guide.
The default is 1, which limits the optimizer to plans
with only one ESP per CPU for a given operator.
Allowable values: 1, >1.
MDAM_SCAN_METHOD Enables (ON) or disables (OFF) the
MultiDimensional Access Method (MDAM). In certain
situations, the optimizer might choose MDAM
inappropriately, causing poor performance.
SQL/MP Considerations: SQL/MP users know this
attribute as CONTROL TABLE MDAM ENABLE.
The default is ON.
Attribute Setting