Class ExchangeRemoveConstantKeysRule

All Implemented Interfaces:
SubstitutionRule, TransformationRule

@Enclosing public class ExchangeRemoveConstantKeysRule extends RelRule<ExchangeRemoveConstantKeysRule.Config> implements SubstitutionRule
Planner rule that removes keys from a Exchange if those keys are known to be constant.

For example, SELECT key,value FROM (SELECT 1 AS key, value FROM src) r DISTRIBUTE BY key can be reduced to SELECT 1 AS key, value FROM src.

See Also: