Class TableScanResultSet

java.lang.Object

org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl

org.apache.derby.impl.sql.execute.NoPutResultSetImpl

org.apache.derby.impl.sql.execute.ScanResultSet

org.apache.derby.impl.sql.execute.TableScanResultSet

All Implemented Interfaces:

Cloneable, CursorResultSet, NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

Direct Known Subclasses:

BulkTableScanResultSet, MultiProbeTableScanResultSet, ValidateCheckConstraintResultSet

class TableScanResultSet
extends ScanResultSet
implements CursorResultSet, Cloneable

Takes a table and a table filter and returns the table's rows satisfying the filter as a result set. There are several things we could do during object construction that are done in the open and next calls, to improve performance.

Nested Class Summary

Nested classes/interfaces inherited from class BasicNoPutResultSetImpl

BasicNoPutResultSetImpl.FieldComparator

Field Summary

Fields

Modifier and Type	Field	Description
boolean	coarserLock
protected long	conglomId
protected boolean	currentRowIsValid
protected DynamicCompiledOpenConglomInfo	dcoci
private long	estimatedRowCount
protected boolean	firstScan
boolean	forUpdate
protected int[]	indexCols
boolean	isConstraint
protected boolean	isKeyed
protected boolean	nextDone
boolean	oneRowScan
protected BackingStoreHashtable	past2FutureTbl	This field is used by beetle 3865, updateable cursor using index.
Qualifier[][]	qualifiers
protected boolean	qualify
private RowLocation	rlTemplate
int	rowsPerRead
protected long	rowsThisScan
protected boolean	runTimeStatisticsOn
(package private) final boolean	sameStartStopPosition
protected ScanController	scanController
protected boolean	scanControllerOpened
private Properties	scanProperties
protected boolean	scanRepositioned
protected StaticCompiledOpenConglomInfo	scoci
protected GeneratedMethod	startKeyGetter
protected ExecIndexRow	startPosition
String	startPositionString
protected int	startSearchOperator
protected GeneratedMethod	stopKeyGetter
protected ExecIndexRow	stopPosition
String	stopPositionString
protected int	stopSearchOperator
String	userSuppliedOptimizerOverrides

Fields inherited from class ScanResultSet

accessedCols, candidate, fetchRowLocations, indexName, isolationLevel, lockMode, resultRowBuilder, tableName

Fields inherited from class NoPutResultSetImpl

checkNullCols, clonedExecRow, cncLen, resultSetNumber, targetResultSet

Fields inherited from class 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 NoPutResultSet

ABSOLUTE, FIRST, LAST, NEXT, PREVIOUS, RELATIVE, TEMPORARY_RESULT_SET_NUMBER

Fields inherited from interface ResultSet

CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST

Constructor Summary

Constructors

Constructor

Description

TableScanResultSet(long conglomId, StaticCompiledOpenConglomInfo scoci, Activation activation, int resultRowTemplate, int resultSetNumber, GeneratedMethod startKeyGetter, int startSearchOperator, GeneratedMethod stopKeyGetter, int stopSearchOperator, boolean sameStartStopPosition, Qualifier[][] qualifiers, String tableName, String userSuppliedOptimizerOverrides, String indexName, boolean isConstraint, boolean forUpdate, int colRefItem, int indexColItem, int lockMode, boolean tableLocked, int isolationLevel, int rowsPerRead, boolean oneRowScan, double optimizerEstimatedRowCount, double optimizerEstimatedCost)

Method Summary

Modifier and Type	Method	Description
protected boolean	canGetInstantaneousLocks()	Can we get instantaneous locks when getting share row locks at READ COMMITTED.
Object	clone()	Shallow clone this result set.
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 (if any) from the scan (if open).
RowLocation	getRowLocation()	This result set has its row location from the last fetch done.
Properties	getScanProperties()
long	getTimeSpent(int type)	Return the total amount of time spent in this ResultSet
(package private) void	initStartAndStopKey()	Initialize the startPosition and stopPosition fields which are used to limit the rows returned by the scan.
boolean	isForUpdate()	Is this ResultSet or it's source result set for update
(package private) boolean	loopControl(boolean moreRows)
void	openCore()	open a scan on the table. scan parameters are evaluated at each open, so there is probably some way of altering their values...
protected void	openScanController(TransactionController tc)
void	positionScanAtRowLocation(RowLocation rl)	Positions the cursor in the specified rowLocation.
private String	printPosition(int searchOperator, GeneratedMethod positionGetter, ExecIndexRow positioner)	Return a start or stop positioner as a String.
String	printStartPosition()	Print an array of Qualifiers to the trace stream.
String	printStopPosition()
void	reopenCore()	Reopen a table scan.
protected void	reopenScanController()
boolean	requiresRelocking()	Do we need to relock the row when going to the heap.
protected final void	setRowCountIfPossible(long rowsThisScan)	Update the number of rows in the scan controller.

Methods inherited from class ScanResultSet

getScanIsolationLevel, initIsolationLevel, setRowLocationsState, toXML

Methods inherited from class NoPutResultSetImpl

clearCurrentRow, clearOrderableCache, closeRowSource, getCursorName, getNextRowFromRowSource, getResultDescription, getValidColumns, markRowAsDeleted, needsRowLocation, needsRowLocationForDeferredCheckConstraints, needsToClone, offendingRowLocation, printQualifiers, resultSetNumber, rowLocation, setCurrentRow, setHasDeferrableChecks, setNeedsRowLocation, setTargetResultSet, skipRow, skipScan, unpackHashValue, updateRow

Methods inherited from class BasicNoPutResultSetImpl

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

Methods inherited from class Object

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

Methods inherited from interface 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, toXML

Field Details

scanController

protected ScanController scanController

scanControllerOpened

protected boolean scanControllerOpened

isKeyed

protected boolean isKeyed

firstScan

protected boolean firstScan

startPosition

protected ExecIndexRow startPosition

stopPosition

protected ExecIndexRow stopPosition

conglomId

protected long conglomId

dcoci

protected DynamicCompiledOpenConglomInfo dcoci

scoci

protected StaticCompiledOpenConglomInfo scoci

startKeyGetter

protected GeneratedMethod startKeyGetter

startSearchOperator

protected int startSearchOperator

stopKeyGetter

protected GeneratedMethod stopKeyGetter

stopSearchOperator

protected int stopSearchOperator

qualifiers

public Qualifier[][] qualifiers

userSuppliedOptimizerOverrides

public String userSuppliedOptimizerOverrides

runTimeStatisticsOn

protected boolean runTimeStatisticsOn

indexCols

protected int[] indexCols

rowsPerRead

public int rowsPerRead

forUpdate

public boolean forUpdate

sameStartStopPosition

final boolean sameStartStopPosition

nextDone

protected boolean nextDone

rlTemplate

private RowLocation rlTemplate

scanProperties

private Properties scanProperties

startPositionString

public String startPositionString

stopPositionString

public String stopPositionString

isConstraint

public boolean isConstraint

coarserLock

public boolean coarserLock

oneRowScan

public boolean oneRowScan

rowsThisScan

protected long rowsThisScan

estimatedRowCount

private long estimatedRowCount

past2FutureTbl

protected BackingStoreHashtable past2FutureTbl

This field is used by beetle 3865, updateable cursor using index. It is a hash table containing updated rows that are thrown into future direction of the index scan, and as a result we'll hit it again but should skip it. The hash table will spill to disk if it grows too big to be kept in memory.

qualify

protected boolean qualify

currentRowIsValid

protected boolean currentRowIsValid

scanRepositioned

protected boolean scanRepositioned

Constructor Details

TableScanResultSet

TableScanResultSet(long conglomId,
 StaticCompiledOpenConglomInfo scoci,
 Activation activation,
 int resultRowTemplate,
 int resultSetNumber,
 GeneratedMethod startKeyGetter,
 int startSearchOperator,
 GeneratedMethod stopKeyGetter,
 int stopSearchOperator,
 boolean sameStartStopPosition,
 Qualifier[][] qualifiers,
 String tableName,
 String userSuppliedOptimizerOverrides,
 String indexName,
 boolean isConstraint,
 boolean forUpdate,
 int colRefItem,
 int indexColItem,
 int lockMode,
 boolean tableLocked,
 int isolationLevel,
 int rowsPerRead,
 boolean oneRowScan,
 double optimizerEstimatedRowCount,
 double optimizerEstimatedCost)
            throws StandardException

Throws:

StandardException

Method Details

openCore

public void openCore()
              throws StandardException

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

Specified by:

openCore in interface NoPutResultSet

Throws:

StandardException - thrown on failure to open

initStartAndStopKey

void initStartAndStopKey()
                  throws StandardException

Initialize the startPosition and stopPosition fields which are used to limit the rows returned by the scan.

Throws:

StandardException

openScanController

protected void openScanController(TransactionController tc)
                           throws StandardException

Throws:

StandardException

reopenScanController

protected void reopenScanController()
                             throws StandardException

Throws:

StandardException

reopenCore

public void reopenCore()
                throws StandardException

Reopen a table scan. Here we take advantage of the reopenScan() interface on scanController for optimimal performance on joins where we are an inner table.

Specified by:

reopenCore in interface NoPutResultSet

Overrides:

reopenCore in class BasicNoPutResultSetImpl

Throws:

StandardException - thrown on failure to open

See Also:

• NoPutResultSet.openCore()

loopControl

boolean loopControl(boolean moreRows)
             throws StandardException

Throws:

StandardException

getNextRowCore

public ExecRow getNextRowCore()
                       throws StandardException

Return the next row (if any) from the scan (if open).

Specified by:

getNextRowCore in interface NoPutResultSet

Specified by:

getNextRowCore in class BasicNoPutResultSetImpl

Returns:

the next row in the result

Throws:

StandardException - thrown on failure to get next row

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 ScanResultSet

Throws:

StandardException - 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. If the cursor is closed, or the row has been deleted a null is returned.

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, the row has been deleted, or no longer qualifies (for forward only result sets) a null is returned.

Specified by:

getCurrentRow in interface CursorResultSet

Returns:

the last row returned;

Throws:

StandardException - thrown on failure.

See Also:

• CursorResultSet

positionScanAtRowLocation

public void positionScanAtRowLocation(RowLocation rl)
                               throws StandardException

Description copied from interface: NoPutResultSet

Positions the cursor in the specified rowLocation. Used for scrollable insensitive result sets in order to position the cursor back to a row that has already be visited.

Specified by:

positionScanAtRowLocation in interface NoPutResultSet

Overrides:

positionScanAtRowLocation in class NoPutResultSetImpl

Parameters:

rl - row location of the current cursor row

Throws:

StandardException - thrown on failure to get location from storage engine

See Also:

• Also sets qualify to false so that later calls to getCurrentRow will not attempt to re-qualify the current row.

printStartPosition

public String printStartPosition()

Print an array of Qualifiers to the trace stream.

printStopPosition

public String printStopPosition()

printPosition

private String printPosition(int searchOperator,
 GeneratedMethod positionGetter,
 ExecIndexRow positioner)

Return a start or stop positioner as a String. If we already generated the information, then use that. Otherwise, invoke the activation to get it.

getScanProperties

public Properties getScanProperties()

requiresRelocking

public boolean requiresRelocking()

Description copied from interface: NoPutResultSet

Do we need to relock the row when going to the heap.

Specified by:

requiresRelocking in interface NoPutResultSet

Overrides:

requiresRelocking in class BasicNoPutResultSetImpl

Returns:

Whether or not we need to relock the row when going to the heap.

See Also:

• NoPutResultSet.requiresRelocking()

setRowCountIfPossible

protected final void setRowCountIfPossible(long rowsThisScan)
                                    throws StandardException

Update the number of rows in the scan controller. NOTE: It would be more efficient to only update the scan controller if the optimizer's estimated number of rows were wrong by more than some threshold (like 10%). This would require a little more work than I have the time for now, however, as the row estimate that is given to this result set is the total number of rows for all scans, not the number of rows per scan.

Parameters:

rowsThisScan - The number of rows to update the scanController to

Throws:

StandardException - Thrown on error

canGetInstantaneousLocks

protected boolean canGetInstantaneousLocks()

Can we get instantaneous locks when getting share row locks at READ COMMITTED.

Specified by:

canGetInstantaneousLocks in class ScanResultSet

isForUpdate

public boolean isForUpdate()

Is this ResultSet or it's source result set for update

Specified by:

isForUpdate in interface NoPutResultSet

Overrides:

isForUpdate in class NoPutResultSetImpl

Returns:

Whether or not the result set is for update.

clone

public Object clone()

Shallow clone this result set. Used in trigger reference. beetle 4373.

Overrides:

clone in class Object