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

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

All Implemented Interfaces:

CursorResultSet, NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

Direct Known Subclasses:

DistinctScalarAggregateResultSet

 class ScalarAggregateResultSet
extends GenericAggregateResultSet
implements CursorResultSet

This ResultSet evaluates scalar, non distinct aggregates. It will scan the entire source result set and calculate the scalar aggregates when scanning the source during the first call to next().

Field Summary

protected int	countOfRows
protected boolean	isInSortedOrder
private boolean	nextSatisfied
int	rowsInput
boolean	singleInputRow
protected ExecIndexRow	sourceExecIndexRow

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

aggInfoList, aggregates, originalSource, source

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

checkNullCols, clonedExecRow, cncLen, resultSetNumber, targetResultSet

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

activation, beginTime, closeTime, compactRow, constructorTime, currentRow, endExecutionTime, finished, isOpen, isTopResultSet, nextTime, numOpens, openTime, optimizerEstimatedCost, optimizerEstimatedRowCount, resultDescription, rowsFiltered, rowsSeen, startExecutionTime, subqueryTrackingArray

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

ScalarAggregateResultSet(NoPutResultSet s, boolean isInSortedOrder, int aggregateItem, Activation a, int ra, int resultSetNumber, boolean singleInputRow, double optimizerEstimatedRowCount, double optimizerEstimatedCost)
Constructor

Method Summary

protected void	accumulateScalarAggregation(ExecRow inputRow, ExecRow accumulateRow, boolean hasDistinctAggregates) Run accumulation on every aggregate in this row.
void	close() If the result set has been opened, close the open scan.
ExecRow	getCurrentRow() This result set has its row from the last fetch done.
ExecRow	getNextRowCore() Return the next row.
ExecIndexRow	getRowFromResultSet(boolean doClone) Get a row from the input result set.
RowLocation	getRowLocation() This result set has its row location from the last fetch done.
long	getTimeSpent(int type) Return the total amount of time spent in this ResultSet
private void	initializeScalarAggregation(ExecRow row)
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.GenericAggregateResultSet

finish, finishAggregation, getRowTemplate, getSortAggregators

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

clearCurrentRow, clearOrderableCache, closeRowSource, getCursorName, getNextRowFromRowSource, getResultDescription, getValidColumns, isForUpdate, markRowAsDeleted, needsRowLocation, needsToClone, positionScanAtRowLocation, printQualifiers, resultSetNumber, rowLocation, setCurrentRow, setNeedsRowLocation, setTargetResultSet, skipRow, skipScan, updateRow

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

addWarning, attachStatementContext, checkCancellationFlag, checkRowPosition, cleanUp, dumpTimeStats, finishAndRTS, getAbsoluteRow, getActivation, getAutoGeneratedKeysResultset, getBeginExecutionTimestamp, getCompactRow, getCurrentTimeMillis, getElapsedMillis, getEndExecutionTimestamp, getEstimatedRowCount, getExecuteTime, getExecutionFactory, getFirstRow, getLanguageConnectionContext, getLastRow, getNextRow, getPointOfAttachment, getPreviousRow, getRelativeRow, getRowNumber, getScanIsolationLevel, getSubqueryTrackingArray, getTransactionController, getWarnings, isClosed, markAsTopResultSet, modifiedRowCount, open, recordConstructorTime, requiresRelocking, returnsRows, setAfterLastRow, setBeforeFirstRow, setCompactRow, setCompatRow

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

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

Field Detail

rowsInput

public int rowsInput

singleInputRow

public boolean singleInputRow

isInSortedOrder

protected boolean isInSortedOrder

sourceExecIndexRow

protected ExecIndexRow sourceExecIndexRow

nextSatisfied

private boolean nextSatisfied

countOfRows

protected int countOfRows

Constructor Detail

ScalarAggregateResultSet

ScalarAggregateResultSet(NoPutResultSet s,
                         boolean isInSortedOrder,
                         int aggregateItem,
                         Activation a,
                         int ra,
                         int resultSetNumber,
                         boolean singleInputRow,
                         double optimizerEstimatedRowCount,
                         double optimizerEstimatedCost)
                   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 - saved object that builds 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

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

Specified by:

getNextRowCore in class BasicNoPutResultSetImpl

Returns:

the next row in the result

Throws:

StandardException - thrown on failure.

StandardException - ResultSetNotOpen thrown if not yet open.

See Also:

NoPutResultSet.getNextRowCore()

close

public void close()
           throws StandardException

If the result set has been opened, close the open scan.

Specified by:

close in interface ResultSet

Overrides:

close in class NoPutResultSetImpl

Throws:

StandardException - thrown on error

getTimeSpent

public long getTimeSpent(int type)

Return the total amount of time spent in this ResultSet

Specified by:

getTimeSpent in interface ResultSet

Parameters:

type - CURRENT_RESULTSET_ONLY - time spent only in this ResultSet ENTIRE_RESULTSET_TREE - time spent in this ResultSet and below.

Returns:

long The total amount of time spent (in milliseconds).

getRowLocation

public RowLocation getRowLocation()
                           throws StandardException

This result set has its row location from the last fetch done. Always returns null.

Specified by:

getRowLocation in interface CursorResultSet

Returns:

the row location of the current cursor row.

Throws:

StandardException - thrown on failure to get row location

See Also:

CursorResultSet

getCurrentRow

public ExecRow getCurrentRow()
                      throws StandardException

This result set has its row from the last fetch done. If the cursor is closed, a null is returned.

Specified by:

getCurrentRow in interface CursorResultSet

Returns:

the last row returned;

Throws:

StandardException - thrown on failure.

See Also:

CursorResultSet

getRowFromResultSet

public ExecIndexRow getRowFromResultSet(boolean doClone)
                                 throws StandardException

Get a row from the input result set.

Parameters:

doClone - - true of the row should be cloned

Throws:

StandardException - Thrown on error

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 BasicNoPutResultSetImpl

Throws:

StandardException - thrown if cursor finished.

See Also:

NoPutResultSet.openCore()

accumulateScalarAggregation

protected void accumulateScalarAggregation(ExecRow inputRow,
                                           ExecRow accumulateRow,
                                           boolean hasDistinctAggregates)
                                    throws StandardException

Run accumulation on every aggregate in this row. This method is useful when draining the source or sorter, depending on whether or not there were any distinct aggregates. Remember, if there are distinct aggregates, then the non-distinct aggregates were calculated on the way into the sorter and only the distinct aggregates will be accumulated here. Otherwise, all aggregates will be accumulated here.

Parameters:

inputRow - the input row

accumulateRow - the row with the accumulator (may be the same as the input row.

hasDistinctAggregates - does this scan have distinct aggregates. Used to figure out whether to merge or accumulate nondistinct aggregates.

Throws:

StandardException - Thrown on error

initializeScalarAggregation

private void initializeScalarAggregation(ExecRow row)
                                  throws StandardException

Throws:

StandardException