Class BTreeForwardScan
- java.lang.Object
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- org.apache.derby.impl.store.access.btree.OpenBTree
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- org.apache.derby.impl.store.access.btree.BTreeScan
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- org.apache.derby.impl.store.access.btree.BTreeForwardScan
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- 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
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Field Summary
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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
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Fields inherited from class org.apache.derby.impl.store.access.btree.OpenBTree
btree_undo, container, err_containerid, init_lock_level, init_open_user_scans, runtime_mem
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Fields inherited from interface org.apache.derby.iapi.store.access.ScanController
GE, GT, NA
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Constructor Summary
Constructors Constructor Description BTreeForwardScan()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected int
fetchRows(BTreeRowPosition pos, DataValueDescriptor[][] row_array, RowLocation[] rowloc_array, BackingStoreHashtable hash_table, long max_rowcnt, int[] key_column_numbers)
Fetch the next N rows from the table.protected void
positionAtStartPosition(BTreeRowPosition pos)
Position scan at "start" position.-
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, isEmpty, isHeldAfterCommit, isKeyed, newRowLocationTemplate, next, positionAtDoneScan, positionAtDoneScanFromClose, positionAtNextPage, positionAtPreviousPage, positionAtRowLocation, positionAtStartForForwardScan, process_qualifier, reopenScan, reopenScanByRowLocation, replace, reposition, savePositionAndReleasePage, savePositionAndReleasePage, toString
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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
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.apache.derby.iapi.store.access.GenericScanController
isTableLocked
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Methods inherited from interface org.apache.derby.iapi.store.access.RowCountable
getEstimatedRowCount, setEstimatedRowCount
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Method Detail
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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 classBTreeScan
- Throws:
StandardException
- Standard exception policy.
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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 classBTreeScan
- Throws:
StandardException
- Standard exception policy.
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