org.apache.derby.impl.sql.execute
Class DistinctScalarAggregateResultSet

java.lang.Object
  org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl
      org.apache.derby.impl.sql.execute.NoPutResultSetImpl
          org.apache.derby.impl.sql.execute.GenericAggregateResultSet
              org.apache.derby.impl.sql.execute.ScalarAggregateResultSet
                  org.apache.derby.impl.sql.execute.DistinctScalarAggregateResultSet

All Implemented Interfaces:

CursorResultSet, NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

public class DistinctScalarAggregateResultSet

extends ScalarAggregateResultSet

This ResultSet evaluates scalar aggregates where 1 (or more, in the future) of the aggregates are distinct. It will scan the entire source result set and calculate the scalar aggregates when scanning the source during the first call to next().

Author:

jerry (broken out from SortResultSet)

Field Summary

private boolean	dropDistinctAggSort
private int	maxRowSize
private ColumnOrdering[]	order
private ScanController	scanController
private boolean	sorted
private long	sortId
private ExecIndexRow	sortResultRow

Fields inherited from class org.apache.derby.impl.sql.execute.ScalarAggregateResultSet

activation, aggInfoList, aggregates, beginTime, checkGM, checkNullCols, clonedExecRow, closeCleanup, closeTime, cncLen, compactRow, constructorTime, countOfRows, currentRow, endExecutionTime, finished, heapConglomerate, indent, isInSortedOrder, isOpen, isTopResultSet, lcc, nextTime, numOpens, openTime, optimizerEstimatedCost, optimizerEstimatedRowCount, originalSource, resultDescription, resultSetNumber, rowAllocator, rowsFiltered, rowsInput, rowsSeen, singleInputRow, sortTemplateRow, source, sourceDepth, sourceExecIndexRow, startExecutionTime, subIndent, subqueryTrackingArray, targetResultSet

Fields inherited from interface org.apache.derby.iapi.sql.ResultSet

CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST

Fields inherited from interface org.apache.derby.iapi.sql.execute.NoPutResultSet

ABSOLUTE, FIRST, LAST, NEXT, PREVIOUS, RELATIVE

Constructor Summary

DistinctScalarAggregateResultSet(NoPutResultSet s, boolean isInSortedOrder, int aggregateItem, int orderingItem, Activation a, GeneratedMethod ra, int maxRowSize, int resultSetNumber, boolean singleInputRow, double optimizerEstimatedRowCount, double optimizerEstimatedCost, GeneratedMethod c)
Constructor

Method Summary

protected void	closeSource() Close the source of whatever we have been scanning.
ExecRow	getNextRowCore() Return the next row.
ExecIndexRow	getRowFromResultSet(boolean doClone) Get a row from the sorter.
private ScanController	loadSorter() Load up the sorter.
void	openCore() Open the scan.
void	reopenCore() reopen a scan on the table. scan parameters are evaluated at each open, so there is probably some way of altering their values...

Methods inherited from class org.apache.derby.impl.sql.execute.ScalarAggregateResultSet

accumulateScalarAggregation, addWarning, attachStatementContext, checkRowPosition, cleanUp, clearCurrentRow, clearOrderableCache, close, closeRowSource, dumpTimeStats, finish, finishAggregation, finishAndRTS, getAbsoluteRow, getAutoGeneratedKeysResultset, getBeginExecutionTimestamp, getCompactRow, getCurrentRow, getCurrentTimeMillis, getCursorName, getElapsedMillis, getEndExecutionTimestamp, getEstimatedRowCount, getExecuteTime, getExecutionFactory, getFirstRow, getLanguageConnectionContext, getLastRow, getNextRow, getNextRowFromRowSource, getPointOfAttachment, getPreviousRow, getRelativeRow, getResultDescription, getRowLocation, getRowNumber, getScanIsolationLevel, getSortAggregators, getSubqueryTrackingArray, getTimeSpent, getTransactionController, getValidColumns, getWarnings, isClosed, isForUpdate, markAsTopResultSet, modifiedRowCount, needsRowLocation, needsToClone, open, printQualifiers, requiresRelocking, resultSetNumber, returnsRows, rowLocation, setAfterLastRow, setBeforeFirstRow, setCheckConstraints, setCompactRow, setCompatRow, setCurrentRow, setHeapConglomerate, setNeedsRowLocation, setTargetResultSet, skipRow, skipScan

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.derby.iapi.sql.ResultSet

checkRowPosition, cleanUp, finish, getAbsoluteRow, getAutoGeneratedKeysResultset, getBeginExecutionTimestamp, getCursorName, getEndExecutionTimestamp, getExecuteTime, getFirstRow, getLastRow, getNextRow, getPreviousRow, getRelativeRow, getResultDescription, getRowNumber, getSubqueryTrackingArray, getWarnings, isClosed, modifiedRowCount, open, returnsRows, setAfterLastRow, setBeforeFirstRow

Field Detail

order

private ColumnOrdering[] order

maxRowSize

private int maxRowSize

dropDistinctAggSort

private boolean dropDistinctAggSort

sortId

private long sortId

scanController

private ScanController scanController

sortResultRow

private ExecIndexRow sortResultRow

sorted

private boolean sorted

Constructor Detail

DistinctScalarAggregateResultSet

public DistinctScalarAggregateResultSet(NoPutResultSet s,
                                        boolean isInSortedOrder,
                                        int aggregateItem,
                                        int orderingItem,
                                        Activation a,
                                        GeneratedMethod ra,
                                        int maxRowSize,
                                        int resultSetNumber,
                                        boolean singleInputRow,
                                        double optimizerEstimatedRowCount,
                                        double optimizerEstimatedCost,
                                        GeneratedMethod c)
                                 throws StandardException

Constructor

Parameters:

s - input result set

isInSortedOrder - true if the source results are in sorted order

aggregateItem - indicates the number of the SavedObject off of the PreparedStatement that holds the AggregatorInfoList used by this routine.

a - activation

ra - generated method to build an empty output row

resultSetNumber - The resultSetNumber for this result set

Throws:

StandardException - Thrown on error

Method Detail

openCore

public void openCore()
              throws StandardException

Open the scan. Load the sorter and prepare to get rows from it.

Specified by:

openCore in interface NoPutResultSet

Overrides:

openCore in class ScalarAggregateResultSet

Throws:

StandardException - thrown if cursor finished.

getNextRowCore

public ExecRow getNextRowCore()
                       throws StandardException

Return the next row. If it is a scalar aggregate scan

Specified by:

getNextRowCore in interface NoPutResultSet

Overrides:

getNextRowCore in class ScalarAggregateResultSet

Returns:

the next row in the result

Throws:

StandardException - thrown on failure.

StandardException - ResultSetNotOpen thrown if not yet open.

reopenCore

public void reopenCore()
                throws StandardException

reopen a scan on the table. scan parameters are evaluated at each open, so there is probably some way of altering their values...

Specified by:

reopenCore in interface NoPutResultSet

Overrides:

reopenCore in class ScalarAggregateResultSet

Throws:

StandardException - thrown if cursor finished.

getRowFromResultSet

public ExecIndexRow getRowFromResultSet(boolean doClone)
                                 throws StandardException

Get a row from the sorter. Side effects: sets currentRow.

Overrides:

getRowFromResultSet in class ScalarAggregateResultSet

Parameters:

doClone - - true of the row should be cloned

Throws:

StandardException - Thrown on error

closeSource

protected void closeSource()
                    throws StandardException

Close the source of whatever we have been scanning.

Throws:

StandardException - thrown on error

loadSorter

private ScanController loadSorter()
                           throws StandardException

Load up the sorter. Feed it every row from the source scan. If we have a vector aggregate, initialize the aggregator for each source row. When done, close the source scan and open the sort. Return the sort scan controller.

Returns:

the sort controller

Throws:

StandardException - thrown on failure.