Top Description Fields Constructors Methods
org.apache.derby.impl.store.access.btree

public Class BTreeForwardScan

extends BTreeScan
Class Inheritance
Known Direct Subclasses
org.apache.derby.impl.store.access.btree.index.B2IForwardScan
Imports
org.apache.derby.shared.common.reference.SQLState, org.apache.derby.shared.common.sanity.SanityManager, org.apache.derby.shared.common.error.StandardException, org.apache.derby.iapi.store.access.ScanController, .BackingStoreHashtable, org.apache.derby.iapi.store.raw.RecordHandle, org.apache.derby.iapi.types.DataValueDescriptor, .RowLocation
A b-tree scan controller corresponds to an instance of an open b-tree scan.

Concurrency Notes

The concurrency rules are derived from OpenBTree.

See Also
OpenBTree

Field Summary

Inherited from org.apache.derby.impl.store.access.btree.BTreeScan:
fetchNext_one_slot_arrayinit_fetchDescinit_forUpdateinit_holdinit_lock_fetch_descinit_qualifierinit_rawtraninit_scanColumnListinit_startKeyValueinit_startSearchOperatorinit_stopKeyValueinit_stopSearchOperatorinit_templateinit_useUpdateLockslock_operationSCAN_DONESCAN_HOLD_INITSCAN_HOLD_INPROGRESSSCAN_INITSCAN_INPROGRESSscan_positionscan_statestat_numdeleted_rows_visitedstat_numpages_visitedstat_numrows_qualifiedstat_numrows_visited

Constructor Summary

AccessConstructor and Description
public
BTreeForwardScan()

Method Summary

Modifier and TypeMethod and Description
protected int
fetchRows(BTreeRowPosition pos, DataValueDescriptor[][] row_array, RowLocation[] rowloc_array, BackingStoreHashtable hash_table, long max_rowcnt, int[] key_column_numbers)

Implements abstract org.apache.derby.impl.store.access.btree.BTreeScan.fetchRows.

Fetch the next N rows from the table.

protected void
positionAtStartPosition(BTreeRowPosition pos)

Implements abstract org.apache.derby.impl.store.access.btree.BTreeScan.positionAtStartPosition.

Position scan at "start" position.

Inherited from org.apache.derby.impl.store.access.btree.BTreeScan:
closecloseForEndTransactiondeletedidNotQualifydoesCurrentPositionQualifyfetchfetchLocationfetchNextfetchNextGroupfetchNextGroupfetchSetfetchWithoutQualifygetCurrentRecordHandleForDebugginggetScanInfoinitisCurrentPositionDeletedisEmptyisHeldAfterCommitisKeyednewRowLocationTemplatenextpositionAtDoneScanpositionAtDoneScanFromClosepositionAtNextPagepositionAtPreviousPagepositionAtRowLocationpositionAtStartForForwardScanprocess_qualifierreopenScanreopenScanByRowLocationreplacerepositionsavePositionAndReleasePagesavePositionAndReleasePagetoString

Constructor Detail

BTreeForwardScanback to summary
public BTreeForwardScan()

Method Detail

fetchRowsback to summary
protected int fetchRows(BTreeRowPosition pos, DataValueDescriptor[][] row_array, RowLocation[] rowloc_array, BackingStoreHashtable hash_table, long max_rowcnt, int[] key_column_numbers) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.BTreeScan.fetchRows.

Fetch the next N rows from the table.

Utility routine used by both fetchSet() and fetchNextGroup().

Exceptions
StandardException:
Standard exception policy.
positionAtStartPositionback to summary
protected void positionAtStartPosition(BTreeRowPosition pos) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.BTreeScan.positionAtStartPosition.

Position scan at "start" position.

Positions the scan to the slot just before the first record to be returned from the scan. Returns the start page latched, and sets "current_slot" to the slot number.

Exceptions
StandardException:
Standard exception policy.