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SQL Development
Optimizing Query Performance
:
Understanding optimization
:
Optimizer phases
:
Index bracket scan optimization
Index bracket scan optimization
This stage checks whether a table scan can be replaced by an index bracket scan. This is possible when a subtree meets the following criteria:
The subtree has a table scan as its leaf node.
An index that includes all the projected columns as part of the index key exists.
Analysis indicates the index bracket scan cost is less than the table scan cost. This is nearly always the case.
The subtree has a table scan as its leaf node.
An index that includes all the projected columns as part of the index key exists.
Analysis indicates the index bracket scan cost is less than the table scan cost. This is nearly always the case.