public static class AbstractConverter.ExpandConversionRule extends RelOptRule
AbstractConverterinto a chain of converters from the source relation to the target traits.
The chain produced is minimal: we have previously built the transitive closure of the graph of conversions, so we choose the shortest chain.
AbstractConverter they are replacing, these
converters are guaranteed to be able to convert any relation of their
calling convention. Furthermore, because they introduce subsets of other
calling conventions along the way, these subsets may spawn more efficient
conversions which are not generally applicable.
AbstractConverters can be messy, so they restrain themselves: they don't fire if the target subset already has an implementation (with less than infinite cost).
|Modifier and Type||Field||Description|
Creates an ExpandConversionRule.
|Modifier and Type||Method||Description|
Receives notification about a rule match.
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
public static final AbstractConverter.ExpandConversionRule INSTANCE
public ExpandConversionRule(RelBuilderFactory relBuilderFactory)
relBuilderFactory- Builder for relational expressions
public void onMatch(RelOptRuleCall call)
call.relsholds the set of relational expressions which match the operands to the rule;
call.relsis the root expression.
Typically a rule would check that the nodes are valid matches, creates
a new expression, then calls back
RelOptRuleCall.transformTo(org.apache.calcite.rel.RelNode, java.util.Map<org.apache.calcite.rel.RelNode, org.apache.calcite.rel.RelNode>) to
register the expression.
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