org.apache.derby.impl.store.access.btree
Class BTreeForwardScan
java.lang.Object
org.apache.derby.impl.store.access.btree.OpenBTree
org.apache.derby.impl.store.access.btree.BTreeScan
org.apache.derby.impl.store.access.btree.BTreeForwardScan
- All Implemented Interfaces:
- ScanManager, GenericScanController, GroupFetchScanController, RowCountable, ScanController
- Direct Known Subclasses:
- B2IForwardScan
public class BTreeForwardScan
- extends BTreeScan
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
Fields inherited from class org.apache.derby.impl.store.access.btree.BTreeScan |
fetchNext_one_slot_array, init_fetchDesc, init_forUpdate, init_hold, init_lock_fetch_desc, init_qualifier, init_rawtran, init_scanColumnList, init_startKeyValue, init_startSearchOperator, init_stopKeyValue, init_stopSearchOperator, init_template, init_useUpdateLocks, lock_operation, SCAN_DONE, SCAN_HOLD_INIT, SCAN_HOLD_INPROGRESS, SCAN_INIT, SCAN_INPROGRESS, scan_position, scan_state, stat_numdeleted_rows_visited, stat_numpages_visited, stat_numrows_qualified, stat_numrows_visited |
Methods inherited from class org.apache.derby.impl.store.access.btree.BTreeScan |
close, closeForEndTransaction, delete, didNotQualify, doesCurrentPositionQualify, fetch, fetchLocation, fetchNext, fetchNextGroup, fetchNextGroup, fetchSet, fetchWithoutQualify, getCurrentRecordHandleForDebugging, getScanInfo, init, isCurrentPositionDeleted, isHeldAfterCommit, isKeyed, newRowLocationTemplate, next, positionAtDoneScan, positionAtDoneScanFromClose, positionAtNextPage, positionAtRowLocation, positionAtStartForForwardScan, process_qualifier, reopenScan, reopenScanByRowLocation, replace, reposition, savePositionAndReleasePage, savePositionAndReleasePage, toString |
Methods inherited from class org.apache.derby.impl.store.access.btree.OpenBTree |
checkConsistency, debugConglomerate, getColumnSortOrderInfo, getConglomerate, getContainer, getContainerHandle, getEstimatedRowCount, getHeight, getHold, getLockingPolicy, getLockLevel, getOpenMode, getRawTran, getRuntimeMem, getSpaceInfo, getXactMgr, init, isClosed, isIndexableRowConsistent, isTableLocked, reopen, setEstimatedRowCount, setLockingPolicy, test_errors |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
BTreeForwardScan
public BTreeForwardScan()
positionAtStartPosition
protected void positionAtStartPosition(BTreeRowPosition pos)
throws StandardException
- 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.
- Specified by:
positionAtStartPosition
in class BTreeScan
- Throws:
StandardException
- Standard exception policy.
fetchRows
protected int fetchRows(BTreeRowPosition pos,
DataValueDescriptor[][] row_array,
RowLocation[] rowloc_array,
BackingStoreHashtable hash_table,
long max_rowcnt,
int[] key_column_numbers)
throws StandardException
- Fetch the next N rows from the table.
Utility routine used by both fetchSet() and fetchNextGroup().
- Specified by:
fetchRows
in class BTreeScan
- Throws:
StandardException
- Standard exception policy.
Apache Derby V10.6 Internals - Copyright © 2004,2007 The Apache Software Foundation. All Rights Reserved.