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SELECTIVITY clause on queries

News


Abstract

The new SELECTIVITY clause can be optionally used to tell SQL Query Engine (SQE) how selective a predicate will be for a query.

Content


Best practice: Use this new, optional SQE hint sparingly. 
SQE includes cost-based optimization and a Global Statistics Manager, which typically results in a query plan and implementation that is optimal and not in need of hinting.
Refer to the Performance and Query Optimization section for usage details: Use SELECTIVITY to supply missing information

See the SQL Reference for syntax details: Search conditions

[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SS9QQS","label":"IBM i 7.4"},"Component":"","Platform":[{"code":"PF012","label":"IBM i"}],"Version":"IBM i 7.4","Edition":"","Line of Business":{"code":"","label":""}}]

Document Information

Modified date:
06 October 2020

UID

ibm16340679