Class CassandraRules.CassandraSortRule
- java.lang.Object
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- org.apache.calcite.plan.RelOptRule
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- org.apache.calcite.adapter.cassandra.CassandraRules.CassandraSortRule
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- Enclosing class:
- CassandraRules
private static class CassandraRules.CassandraSortRule extends RelOptRule
Rule to convert aSort
to aCassandraSort
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Field Summary
Fields Modifier and Type Field Description private static RelOptRuleOperand
CASSANDRA_OP
private static CassandraRules.CassandraSortRule
INSTANCE
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Fields inherited from class org.apache.calcite.plan.RelOptRule
description, operands, relBuilderFactory
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Constructor Summary
Constructors Modifier Constructor Description private
CassandraSortRule()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description private boolean
collationsCompatible(RelCollation sortCollation, RelCollation implicitCollation)
Check if it is possible to exploit native CQL sorting for a given collation.RelNode
convert(Sort sort, CassandraFilter filter)
boolean
matches(RelOptRuleCall call)
Returns whether this rule could possibly match the given operands.void
onMatch(RelOptRuleCall call)
Receives notification about a rule match.private RelFieldCollation.Direction
reverseDirection(RelFieldCollation.Direction direction)
Find the reverse of a given collation direction.-
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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CASSANDRA_OP
private static final RelOptRuleOperand CASSANDRA_OP
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INSTANCE
private static final CassandraRules.CassandraSortRule INSTANCE
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Method Detail
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convert
public RelNode convert(Sort sort, CassandraFilter filter)
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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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collationsCompatible
private boolean collationsCompatible(RelCollation sortCollation, RelCollation implicitCollation)
Check if it is possible to exploit native CQL sorting for a given collation.- Returns:
- True if it is possible to achieve this sort in Cassandra
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reverseDirection
private RelFieldCollation.Direction reverseDirection(RelFieldCollation.Direction direction)
Find the reverse of a given collation direction.- Returns:
- Reverse of the input direction
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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:
ConverterRule
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