Performance Tuning Guide

10.5.7
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Predicate Optimization Rules and Guidelines

When the Data Integration Service rewrites a predicate expression, it applies mathematical logic to the expression to optimize it.

The Data Integration Service might perform any or all of the following actions:

Identifies equivalent variables across predicate expressions in the mapping and generates simplified expressions based on the equivalencies.

Identifies redundant predicates across predicate expressions in the mapping and removes them.

Extracts subexpressions from disjunctive clauses and generates multiple, simplified expressions based on the subexpressions.

Normalizes a predicate expression.

Applies predicate expressions as early as possible in the mapping.

The Data Integration Service might not apply predicate optimization to a mapping when the mapping contains transformations with a datatype mismatch between connected ports.

The Data Integration Service might not apply predicate optimization to a transformation when any of the following conditions are true:

The transformation contains explicit default values for connected ports.

The transformation has side effects.

The transformation does not allow predicates to be moved. For example, a transformation that has side effects might have this restriction.

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Table of Contents

Performance Tuning Guide

Performance Tuning Guide

Predicate Optimization Rules and Guidelines

Predicate Optimization Rules and Guidelines