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Description Adaptive Server IQ 12.4.0
32
Release Bulletin for Digital UNIX
Description
For joins within a query, the IQ optimizer has a choice of several algorithms
for processing the join. This option allows you to override the optimizer’s
cost—based decision when choosing the algorithm to use. It does not override
internal rules that determine whether an algorithm is legal within the query
engine. If you set it to any non-zero value, it affects every join in a query; it
cannot be used to selectively modify one join out of several in a query.
This option is normally used for internal testing, and only experienced DBA's
should use it. The following table describes the valid values for this option and
their action.
9.4.7 Corrections to INSERT LOCATION
These corrections apply to the Adaptive Server IQ Reference Manual and the
Adaptive Server IQ Administration and Performance Guide.
If you plan to use the
INSERT LOCATION command (syntax 3 of the INSERT
command), the Adaptive Server Enterprise server you are connecting to must
exist in the interfaces file on the local machine.
Also, the syntax in the Adaptive Server IQ Reference Manual is incorrect. The
servername.dbname must be enclosed in single quotes, and the
SELECT
statement must be in braces. An example of correct syntax is:
INSERT CUSTOMERS LOCATION ’BOSTON.PUBS2’
Value Action
0 Let the optimizer choose
1 Prefer sort/merge
2 Prefer nested loop
3 Prefer nested loop push-down
4 Prefer hash
5 Prefer hash push-down
6 Prefer join index
-1 Avoid sort/merge
-2 Avoid nested loop
-3 Avoid nested loop push-down
-4 Avoid hash
-5 Avoid hash push-down
–6 Avoid join index