Class SortUnionTransposeRule
- java.lang.Object
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- org.apache.calcite.plan.RelOptRule
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- org.apache.calcite.rel.rules.SortUnionTransposeRule
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public class SortUnionTransposeRule extends RelOptRule
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Field Summary
Fields Modifier and Type Field Description static SortUnionTransposeRule
INSTANCE
Rule instance for Union implementation that does not preserve the ordering of its inputs.static SortUnionTransposeRule
MATCH_NULL_FETCH
Rule instance for Union implementation that preserves the ordering of its inputs.private boolean
matchNullFetch
Whether to match a Sort whoseSort.fetch
is null.-
Fields inherited from class org.apache.calcite.plan.RelOptRule
description, operands, relBuilderFactory
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Constructor Summary
Constructors Modifier Constructor Description private
SortUnionTransposeRule(boolean matchNullFetch)
SortUnionTransposeRule(java.lang.Class<? extends Sort> sortClass, java.lang.Class<? extends Union> unionClass, boolean matchNullFetch, RelBuilderFactory relBuilderFactory, java.lang.String description)
Creates a SortUnionTransposeRule.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
matches(RelOptRuleCall call)
Returns whether this rule could possibly match the given operands.void
onMatch(RelOptRuleCall call)
Receives notification about a rule match.-
Methods inherited from class org.apache.calcite.plan.RelOptRule
any, convert, convert, convertList, convertOperand, convertOperand, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, none, operand, operand, operand, operand, operand, operandJ, operandJ, some, toString, unordered
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Field Detail
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INSTANCE
public static final SortUnionTransposeRule INSTANCE
Rule instance for Union implementation that does not preserve the ordering of its inputs. Thus, it makes no sense to match this rule if the Sort does not have a limit, i.e.,Sort.fetch
is null.
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MATCH_NULL_FETCH
public static final SortUnionTransposeRule MATCH_NULL_FETCH
Rule instance for Union implementation that preserves the ordering of its inputs. It is still worth applying this rule even if the Sort does not have a limit, for the merge of already sorted inputs that the Union can do is usually cheap.
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matchNullFetch
private final boolean matchNullFetch
Whether to match a Sort whoseSort.fetch
is null. Generally this only makes sense if the Union preserves order (and merges).
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Constructor Detail
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SortUnionTransposeRule
private SortUnionTransposeRule(boolean matchNullFetch)
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SortUnionTransposeRule
public SortUnionTransposeRule(java.lang.Class<? extends Sort> sortClass, java.lang.Class<? extends Union> unionClass, boolean matchNullFetch, RelBuilderFactory relBuilderFactory, java.lang.String description)
Creates a SortUnionTransposeRule.
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Method Detail
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matches
public boolean matches(RelOptRuleCall call)
Description copied from class:RelOptRule
Returns whether this rule could possibly match the given operands.This method is an opportunity to apply side-conditions to a rule. The
RelOptPlanner
calls this method after matching all operands of the rule, and before callingRelOptRule.onMatch(RelOptRuleCall)
.In implementations of
RelOptPlanner
which may queue up a matchedRelOptRuleCall
for a long time before callingRelOptRule.onMatch(RelOptRuleCall)
, this method is beneficial because it allows the planner to discard rules earlier in the process.The default implementation of this method returns
true
. It is acceptable for any implementation of this method to give a false positives, that is, to say that the rule matches the operands but haveRelOptRule.onMatch(RelOptRuleCall)
subsequently not generate any successors.The following script is useful to identify rules which commonly produce no successors. You should override this method for these rules:
awk ' /Apply rule/ {rule=$4; ruleCount[rule]++;} /generated 0 successors/ {ruleMiss[rule]++;} END { printf "%-30s %s %s\n", "Rule", "Fire", "Miss"; for (i in ruleCount) { printf "%-30s %5d %5d\n", i, ruleCount[i], ruleMiss[i]; } } ' FarragoTrace.log
- Overrides:
matches
in classRelOptRule
- Parameters:
call
- Rule call which has been determined to match all operands of this rule- Returns:
- whether this RelOptRule matches a given RelOptRuleCall
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onMatch
public void onMatch(RelOptRuleCall call)
Description copied from class:RelOptRule
Receives notification about a rule match. At the time that this method is called,call.rels
holds the set of relational expressions which match the operands to the rule;call.rels[0]
is 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.- Specified by:
onMatch
in classRelOptRule
- Parameters:
call
- Rule call- See Also:
RelOptRule.matches(RelOptRuleCall)
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