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Set query optimization to biased toward outliers.


[SQL]    BiasQueriesAsOutlier=n

n is either 1 or 0. The default value is 0.


When BiasQueriesAsOutlier is enabled (n = 1), InterSystems SQL optimizes for queries that primarily return outlier values. For further details on outlier selectivity, refer to Tune Table in the “Optimizing Tables” chapter in InterSystems SQL Optimization Guide.

BiasQueriesAsOutlier and RTPC cannot both be active at the same time. If both BiasQueriesAsOutlier and RTPC are set to 1, RTPC is activated and the BiasQueriesAsOutlier setting is ignored. When RTPC is set, InterSystems SQL determines whether to use outlier optimization on a per-query basis.

If AdaptiveMode is enabled (set to 1) and BiasQueriesAsOutlier is active and enabled, then Adaptive Mode overrides the BiasQueriesAsOutlier setting and disables outlier bias.


Adaptive Mode replaces the earlier BiasQueriesAsOutlier mechanism. Please contact the WRC is you were previously using this setting and need assistance.

Changing This Parameter

You can change BiasQueriesAsOutlier with the Config.SQLOpens in a new tab class (as described in the class reference) or by editing the CPF in a text editor (as described in the Editing the Active CPF section of the “Introduction to the Configuration Parameter File” chapter in this book).

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