Package org.apache.calcite.adapter.pig

Class PigAggregate

    • Field Detail

      • DISTINCT_FIELD_SUFFIX

        public static final java.lang.String DISTINCT_FIELD_SUFFIX
        See Also:
        Constant Field Values

    • Method Detail

      • copy

        public Aggregate copy​(RelTraitSet traitSet,
                      RelNode input,
                      boolean indicator,
                      ImmutableBitSet groupSet,
                      java.util.List<ImmutableBitSet> groupSets,
                      java.util.List<AggregateCall> aggCalls)
        Description copied from class: Aggregate
        Creates a copy of this aggregate.
        Specified by:
        copy in class Aggregate
        Parameters:
        traitSet - Traits
        input - Input
        indicator - Whether row type should include indicator fields to indicate which grouping set is active; must be true if aggregate is not simple
        groupSet - Bit set of grouping fields
        groupSets - List of all grouping sets; null for just groupSet
        aggCalls - Collection of calls to aggregate functions
        Returns:
        New Aggregate if any parameter differs from the value of this Aggregate, or just this if all the parameters are the same
        See Also:
        Aggregate.copy(org.apache.calcite.plan.RelTraitSet, java.util.List)

      • implement

        public void implement​(PigRel.Implementor implementor)
        Description copied from interface: PigRel
        Converts this node to a Pig Latin statement.
        Specified by:
        implement in interface PigRel

      • getPigAggregateStatement

        private java.lang.String getPigAggregateStatement​(PigRel.Implementor implementor)
        Generates a GROUP BY statement, followed by an optional FOREACH statement for all aggregate functions used. e.g. 
         
 A = GROUP A BY owner;
 A = FOREACH A GENERATE group, SUM(A.pet_num);

      • getTable

        public RelOptTable getTable()
        Override this method so it looks down the tree to find the table this node is acting on.
        Specified by:
        getTable in interface RelNode
        Overrides:
        getTable in class AbstractRelNode
        Returns:
        If this relational expression represents an access to a table, returns that table, otherwise returns null

      • getPigGroupBy

        private java.lang.String getPigGroupBy​(PigRel.Implementor implementor)
        Generates the GROUP BY statement, e.g. A = GROUP A BY (f1, f2);

      • getPigForEachGenerate

        private java.lang.String getPigForEachGenerate​(PigRel.Implementor implementor)
        Generates a FOREACH statement containing invocation of aggregate functions and projection of grouped fields. e.g. A = FOREACH A GENERATE group, SUM(A.pet_num);
        See Also:
        documentation for special meaning of the "group" field after GROUP BY.

      • getPigGenerateCall

        private java.lang.String getPigGenerateCall​(PigRel.Implementor implementor)

      • getPigAggregateCalls

        private java.util.List<java.lang.String> getPigAggregateCalls​(PigRel.Implementor implementor)

      • getPigAggregateCall

        private java.lang.String getPigAggregateCall​(java.lang.String relAlias,
                                             AggregateCall aggCall)

      • getArgNames

        private java.util.List<java.lang.String> getArgNames​(java.lang.String relAlias,
                                                     AggregateCall aggCall)

      • getInputFieldNameForAggCall

        private java.lang.String getInputFieldNameForAggCall​(java.lang.String relAlias,
                                                     AggregateCall aggCall,
                                                     int fieldIndex)

      • getDistinctCalls

        private java.util.List<java.lang.String> getDistinctCalls​(PigRel.Implementor implementor)
        A agg function call like COUNT(DISTINCT COL) in Pig is achieved via two statements in a FOREACH that follows a GROUP statement:
        TABLE = GROUP TABLE ALL;
        TABLE = FOREACH TABLE {
          COL.DISTINCT = DISTINCT COL;
          GENERATE COUNT(COL.DISTINCT) AS C;
        }

      • getInputFieldName

        private java.lang.String getInputFieldName​(int fieldIndex)