net.sf.farrago.fennel.rel
Class FennelWindowRel

java.lang.Object
  org.eigenbase.rel.AbstractRelNode
      org.eigenbase.rel.SingleRel
          net.sf.farrago.fennel.rel.FennelSingleRel
              net.sf.farrago.fennel.rel.FennelWindowRel

All Implemented Interfaces:

Cloneable, FennelRel, RelNode

public class FennelWindowRel
extends FennelSingleRel

FennelWindowRel is the relational expression which computes windowed aggregates inside of Fennel.

A window rel can handle several window aggregate functions, over several partitions, with pre- and post-expressions, and an optional post-filter. Each of the partitions is defined by a partition key (zero or more columns) and a range (logical or physical). The partitions expect the data to be sorted correctly on input to the relational expression.

Rules:

• FennelWindowRule creates this from a CalcRel
• WindowedAggSplitterRule decomposes a CalcRel which contains windowed aggregates into a FennelWindowRel and zero or more CalcRels which do not contain windowed aggregates

Since:

Dec 6, 2004

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/fennel/rel/FennelWindowRel.java#2 $

Author:

jhyde

Nested Class Summary

static class	FennelWindowRel.Partition A Partition is a collection of windowed aggregate expressions which belong to the same FennelWindowRel.Window and have the same partitioning keys.
static class	FennelWindowRel.RexWinAggCall A call to a windowed aggregate function.
static class	FennelWindowRel.Window A Window is a range of input rows, defined by an upper and lower bound.

Field Summary

private RexProgram	inputProgram Program which is applied on an incoming row event.
private RexProgram	outputProgram Program which is applied on an 'row output' event.
private FennelWindowRel.Window[]	windows

Fields inherited from class org.eigenbase.rel.AbstractRelNode

digest, id, rowType, traits

Fields inherited from interface net.sf.farrago.query.FennelRel

FENNEL_EXEC_CONVENTION

Fields inherited from interface org.eigenbase.rel.RelNode

emptyArray

Constructor Summary

protected

FennelWindowRel(RelOptCluster cluster, RelNode child, RelDataType rowType, RexProgram inputProgram, FennelWindowRel.Window[] windows, RexProgram outputProgram) Creates a window relational expression.

Method Summary

FennelWindowRel	clone() Clones this RelNode.
RelOptCost	computeSelfCost(RelOptPlanner planner) Returns the cost of this plan (not including children).
void	explain(RelOptPlanWriter pw)
RexNode[]	getChildExps() Returns an array of this relational expression's child expressions (not including the inputs returned by RelNode.getInputs().
private void	getExplainTerms(List<String> termList, List<Object> valueList)
String[]	getSoleProgram() Assuming that this FennelWindowRel contains one window with one partition, return the add/init/drop programs for that partition.
List<FennelWindowRel.Window>	getWindows()
boolean	isValid(boolean fail) Returns whether this relational expression is valid.
static RexProgram	makeProgram(RexBuilder rexBuilder, RexProgram bottomProgram, List<FennelWindowRel.RexWinAggCall> overList) Creates a program with one output field per windowed aggregate expression.
private static List<RelDataType>	outputProgramInputTypes(RelDataType rowType, FennelWindowRel.Window[] windows)
private List<RexNode>	removeDuplicates(RexToCalcTranslator translator, List<FennelWindowRel.RexWinAggCall> outputExps)
FemExecutionStreamDef	toStreamDef(FennelRelImplementor implementor) Converts this relational expression to FemExecutionStreamDef form.

Methods inherited from class net.sf.farrago.fennel.rel.FennelSingleRel

getCollations, getFarragoTypeFactory, implementFennelChild

Methods inherited from class org.eigenbase.rel.SingleRel

childrenAccept, deriveRowType, getChild, getInputs, getRows, replaceInput

Methods inherited from class org.eigenbase.rel.AbstractRelNode

cloneTraits, collectVariablesSet, collectVariablesUsed, computeDigest, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRowType, getTable, getTraits, getVariablesStopped, inheritTraitsFrom, isAccessTo, isDistinct, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.eigenbase.rel.RelNode

childrenAccept, collectVariablesSet, collectVariablesUsed, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getInputs, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRows, getRowType, getTable, getTraits, getVariablesStopped, isAccessTo, isDistinct, onRegister, recomputeDigest, registerCorrelVariable, replaceInput, setCorrelVariable

Field Detail

inputProgram

private final RexProgram inputProgram

Program which is applied on an incoming row event.

It provides the necessary expressions for the windows to work on. The program always outputs the input fields first, then any necessary expressions.

For example, for the query

select ticker,
sum(amount * price) over last3
from Bids
window last3 as (order by orderid rows 3 preceding),
lastHour (order by orderdate range interval '1' hour preceding),


the program will output the expressions

{orderid, ticker, amount, price, amount * price}

outputProgram

private final RexProgram outputProgram

Program which is applied on an 'row output' event.

Its input is the columns of the current input row, and all accumulators of all windows of all partitions. Its output is the output row.

For example, consider the query

select ticker,
sum(amount * price) over last3,
2 * sum(amount + 1) over lastHour,
from Bids
window last3 as (order by orderid rows 3 preceding),
lastHour (order by orderdate range interval '1' hour preceding),


The program has inputs

{orderid, ticker, amount, price, sum(amount * price) over last3, sum(amount + 1) over lastHour}

and outputs

{$1, $4, 2 * $5}

windows

private final FennelWindowRel.Window[] windows

Constructor Detail

FennelWindowRel

protected FennelWindowRel(RelOptCluster cluster,
                          RelNode child,
                          RelDataType rowType,
                          RexProgram inputProgram,
                          FennelWindowRel.Window[] windows,
                          RexProgram outputProgram)

Creates a window relational expression.

Each FennelWindowRel.Window has a set of FennelWindowRel.Partition objects, and each FennelWindowRel.Partition object has a set of RexOver objects.

Parameters:

cluster - Cluster

child - Input relational expression

rowType - Output row type

inputProgram - Program which computes input expressions for all windows

windows - Windows

outputProgram - Program which computes output row from input columns and all windows

"Precondition:"

inputProgram.getCondition() == null

Method Detail

outputProgramInputTypes

private static List<RelDataType> outputProgramInputTypes(RelDataType rowType,
                                                         FennelWindowRel.Window[] windows)

clone

public FennelWindowRel clone()

Description copied from interface: RelNode

Clones this RelNode.

Traits of the RelNode must be explicitly cloned, using AbstractRelNode.inheritTraitsFrom(AbstractRelNode), as the RelNode may have traits of which it has no knowledge. Example implementation:

     public MyRelNode clone()
     {
         MyRelNode clone = new MyRelNode(...);
         clone.inheritTraitsFrom(this);
         return clone;
     }
 

N.B.: This method must be overridden whenever an existing, concrete RelNode is extended. Otherwise, calling clone() will produce a differently typed RelNode, resulting in invalid or incorrect query plans.

Specified by:

clone in interface RelNode

Specified by:

clone in class AbstractRelNode

Returns:

a clone of this RelNode

getWindows

public List<FennelWindowRel.Window> getWindows()

isValid

public boolean isValid(boolean fail)

Description copied from interface: RelNode

Returns whether this relational expression is valid.

If assertions are enabled, this method is typically called with fail = true, as follows:

assert rel.isValid(true)

This signals that the method can throw an AssertionError if it is not valid.

Specified by:

isValid in interface RelNode

Overrides:

isValid in class AbstractRelNode

Parameters:

fail - Whether to fail if invalid

Returns:

Whether relational expression is valid

getChildExps

public RexNode[] getChildExps()

Description copied from interface: RelNode

Returns an array of this relational expression's child expressions (not including the inputs returned by RelNode.getInputs(). If there are no child expressions, returns an empty array, not null.

Specified by:

getChildExps in interface RelNode

Overrides:

getChildExps in class AbstractRelNode

explain

public void explain(RelOptPlanWriter pw)

Specified by:

explain in interface RelNode

Overrides:

explain in class SingleRel

getExplainTerms

private void getExplainTerms(List<String> termList,
                             List<Object> valueList)

computeSelfCost

public RelOptCost computeSelfCost(RelOptPlanner planner)

Description copied from interface: RelNode

Returns the cost of this plan (not including children). The base implementation throws an error; derived classes should override.

NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getNonCumulativeCost(org.eigenbase.rel.RelNode), which gives plugins a chance to override the rel's default ideas about cost.

Specified by:

computeSelfCost in interface RelNode

Overrides:

computeSelfCost in class AbstractRelNode

toStreamDef

public FemExecutionStreamDef toStreamDef(FennelRelImplementor implementor)

Description copied from interface: FennelRel

Converts this relational expression to FemExecutionStreamDef form. In the process, the relational expression will almost certainly call FennelRelImplementor.visitFennelChild(net.sf.farrago.query.FennelRel, int) on each of its children.

Parameters:

implementor - for generating Java code

Returns:

generated FemExecutionStreamDef

getSoleProgram

public String[] getSoleProgram()

Assuming that this FennelWindowRel contains one window with one partition, return the add/init/drop programs for that partition. For testing purposes.

makeProgram

public static RexProgram makeProgram(RexBuilder rexBuilder,
                                     RexProgram bottomProgram,
                                     List<FennelWindowRel.RexWinAggCall> overList)

Creates a program with one output field per windowed aggregate expression.

Parameters:

rexBuilder - Expression builder

bottomProgram - Calculates the inputs to the program

overList - Aggregate expressions

Returns:

Combined program

See Also:

RexProgramBuilder.mergePrograms(RexProgram, RexProgram, RexBuilder)

"Precondition:"

bottomPogram.getCondition() == null

"Postcondition:"

return.getProjectList().size() == overList.size()

removeDuplicates

private List<RexNode> removeDuplicates(RexToCalcTranslator translator,
                                       List<FennelWindowRel.RexWinAggCall> outputExps)