SQL/MX 3.2 Query Guide (H06.25+, J06.14+)

Accessing SQL/MX Data
HP NonStop SQL/MX Release 3.2 Query Guide—663851-002
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Specifying MDAM

Obtain good performance in situations where previously a full table scan was
needed.

To add rows to a table without suffering performance penalties.
Specifying MDAM
MDAM is enabled by default. Enable means that the SQL/MX compiler can choose to
use MDAM if it will provide a better quality plan. Several SQL/MX compiler control
settings affect MDAM:

CONTROL QUERY DEFAULT provides a system-wide “master” switch for the
current session. You can switch MDAM off or on and enable MDAM if it is disabled.

With CONTROL QUERY SHAPE, you can force columns to be used by MDAM,
and you can also force enumeration algorithms. For more information about
enumeration algorithms, see MDAM’s Use of DENSE and SPARSE Algorithms on
page 2-17.
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