Class BulkTableScanResultSet

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

org.apache.derby.impl.sql.execute.BulkTableScanResultSet

All Implemented Interfaces:

Cloneable, CursorResultSet, NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

class BulkTableScanResultSet
extends TableScanResultSet
implements CursorResultSet

Read a base table or index in bulk. Most of the work for this method is inherited from TableScanResultSet. This class overrides getNextRowCore (and extends re/openCore) to use a row array and fetch rows from the Store in bulk (using fetchNextGroup).

Since it retrieves rows in bulk, locking is not as is usual -- locks may have already been released on rows as they are returned to the user. Hence, this ResultSet is not suitable for a query running Isolation Level 1, cursor stability.

Note that this code is only accessable from an optimizer override. If it makes sense to have the optimizer select bulk reads, then this should probably be rolled into TableScanResultSet.

Nested Class Summary

Nested classes/interfaces inherited from class BasicNoPutResultSetImpl

BasicNoPutResultSetImpl.FieldComparator

Field Summary

Fields

Modifier and Type	Field	Description
private int	baseColumnCount
private int	curRowPosition
private int	numRowsInArray
private static int	OUT_OF_ROWS
private int	resultColumnCount
private DataValueDescriptor[][]	rowArray
private RowLocation[]	rowLocations

Fields inherited from class TableScanResultSet

coarserLock, conglomId, currentRowIsValid, dcoci, firstScan, forUpdate, indexCols, isConstraint, isKeyed, nextDone, oneRowScan, past2FutureTbl, qualifiers, qualify, rowsPerRead, rowsThisScan, runTimeStatisticsOn, sameStartStopPosition, scanController, scanControllerOpened, scanRepositioned, scoci, startKeyGetter, startPosition, startPositionString, startSearchOperator, stopKeyGetter, stopPosition, stopPositionString, stopSearchOperator, 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

BulkTableScanResultSet(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 disableForHoldable, boolean oneRowScan, double optimizerEstimatedRowCount, double optimizerEstimatedCost)

Constructor.

Method Summary

Modifier and Type	Method	Description
private static int	adjustBulkFetchSize(Activation activation, int rowsPerRead, boolean disableForHoldable)	Adjust the bulk fetch size according to the parameters.
protected boolean	canGetInstantaneousLocks()	Can we get instantaneous locks when getting share row locks at READ COMMITTED.
void	close()	If the result set has been opened, close the open scan.
ExecRow	getNextRowCore()	Return the next row (if any) from the scan (if open).
private DataValueDescriptor[]	lopOffRowLocation()	Get a blank row by cloning the candidate row and lopping off the trailing RowLocation column for scans done on behalf of MERGE statements.
void	openCore()	Open up the result set.
protected void	openScanController(TransactionController tc)	Open the scan controller
private int	reloadArray()
void	reopenCore()	Reopen the result set.
boolean	requiresRelocking()	Do we need to relock the row when going to the heap.

Methods inherited from class TableScanResultSet

clone, getCurrentRow, getRowLocation, getScanProperties, getTimeSpent, initStartAndStopKey, isForUpdate, loopControl, positionScanAtRowLocation, printStartPosition, printStopPosition, reopenScanController, setRowCountIfPossible

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 CursorResultSet

getCurrentRow, getRowLocation

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, getTimeSpent, getWarnings, isClosed, modifiedRowCount, open, returnsRows, setAfterLastRow, setBeforeFirstRow, toXML

Field Details

rowArray

private DataValueDescriptor[][] rowArray

rowLocations

private RowLocation[] rowLocations

curRowPosition

private int curRowPosition

numRowsInArray

private int numRowsInArray

baseColumnCount

private int baseColumnCount

resultColumnCount

private int resultColumnCount

OUT_OF_ROWS

private static int OUT_OF_ROWS

Constructor Details

BulkTableScanResultSet

BulkTableScanResultSet(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 disableForHoldable,
 boolean oneRowScan,
 double optimizerEstimatedRowCount,
 double optimizerEstimatedCost)
                throws StandardException

Constructor. Just save off the rowsPerRead argument and pass everything else down to TableScanResultSet

Throws:

StandardException - thrown on failure to open

See Also:

• ResultSetFactory.getBulkTableScanResultSet(Activation, long, int, int, int, GeneratedMethod, int, GeneratedMethod, int, boolean, Qualifier[][], String, String, String, boolean, boolean, int, int, int, boolean, int, int, boolean, boolean, double, double)

Method Details

adjustBulkFetchSize

private static int adjustBulkFetchSize(Activation activation,
 int rowsPerRead,
 boolean disableForHoldable)

Adjust the bulk fetch size according to the parameters. Bulk fetch may be disabled by returning 1 from this method. Disabling of bulk fetch may happen if the cursor is holdable and it contains LOB columns (DERBY-1511) because

Parameters:

activation - the activation for the executing statement

rowsPerRead - how many rows to read in each chunk if a bulk fetch is OK to use

disableForHoldable - whether or not bulk fetch should be disabled for holdable cursors

Returns:

the bulk fetch size to use

openScanController

protected void openScanController(TransactionController tc)
                           throws StandardException

Open the scan controller

Overrides:

openScanController in class TableScanResultSet

Parameters:

tc - transaction controller will open one if null

Throws:

StandardException - thrown on failure to open

openCore

public void openCore()
              throws StandardException

Open up the result set. Delegate most work to TableScanResultSet.openCore(). Create a new array with rows for use in fetchNextGroup().

Specified by:

openCore in interface NoPutResultSet

Overrides:

openCore in class TableScanResultSet

Throws:

StandardException - thrown on failure to open

lopOffRowLocation

private DataValueDescriptor[] lopOffRowLocation()
                                         throws StandardException

Get a blank row by cloning the candidate row and lopping off the trailing RowLocation column for scans done on behalf of MERGE statements.

Throws:

StandardException

reopenCore

public void reopenCore()
                throws StandardException

Reopen the result set. Delegate most work to TableScanResultSet.reopenCore(). Reuse the array of rows.

Specified by:

reopenCore in interface NoPutResultSet

Overrides:

reopenCore in class TableScanResultSet

Throws:

StandardException - thrown on failure to open

See Also:

• NoPutResultSet.openCore()

getNextRowCore

public ExecRow getNextRowCore()
                       throws StandardException

Return the next row (if any) from the scan (if open). Reload the rowArray as necessary.

Specified by:

getNextRowCore in interface NoPutResultSet

Overrides:

getNextRowCore in class TableScanResultSet

Returns:

the next row in the result

Throws:

StandardException - thrown on failure to get next row

See Also:

• NoPutResultSet.getNextRowCore()

reloadArray

private int reloadArray()
                 throws StandardException

Throws:

StandardException

close

public void close()
           throws StandardException

If the result set has been opened, close the open scan. Delegate most of the work to TableScanResultSet.

Specified by:

close in interface ResultSet

Overrides:

close in class TableScanResultSet

Throws:

StandardException - on error

canGetInstantaneousLocks

protected boolean canGetInstantaneousLocks()

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

Overrides:

canGetInstantaneousLocks in class TableScanResultSet

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 TableScanResultSet

Returns:

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

See Also:

• NoPutResultSet.requiresRelocking()