Class B2IMaxScan
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.BTreeMaxScan
org.apache.derby.impl.store.access.btree.index.B2IMaxScan
- All Implemented Interfaces:
ScanManager
,GenericScanController
,GroupFetchScanController
,RowCountable
,ScanController
Scan used to find maximum value in the secondary index.
This class implements an optimized interface to find the maximum row,
for a set of rows between an input start and stop key.
Note most work of this class is inherited from the generic btree implementation.
This class initializes the top level object and deals with locking information
specific to a secondary index implementation of a btree.
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Field Summary
FieldsFields 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_state, stat_numdeleted_rows_visited, stat_numpages_visited, stat_numrows_qualified, stat_numrows_visited
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
Fields inherited from interface org.apache.derby.iapi.store.access.ScanController
GE, GT, NA
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
close()
Close the scan.boolean
closeForEndTransaction
(boolean closeHeldScan) Close the scan, a commit or abort is about to happen.void
init
(TransactionManager xact_manager, Transaction rawtran, int open_mode, int lock_level, LockingPolicy locking_policy, int isolation_level, boolean open_for_locking, FormatableBitSet scanColumnList, B2I conglomerate, B2IUndo undo) Initialize the scan for use.Methods inherited from class org.apache.derby.impl.store.access.btree.BTreeMaxScan
fetchMax, fetchRows, positionAtStartPosition
Methods inherited from class org.apache.derby.impl.store.access.btree.BTreeScan
delete, didNotQualify, doesCurrentPositionQualify, fetch, fetchLocation, fetchNext, fetchNextGroup, fetchNextGroup, fetchSet, fetchWithoutQualify, getCurrentRecordHandleForDebugging, getScanInfo, init, isCurrentPositionDeleted, isHeldAfterCommit, isKeyed, newRowLocationTemplate, next, positionAtDoneScan, positionAtDoneScanFromClose, positionAtNextPage, positionAtPreviousPage, positionAtRowLocation, positionAtStartForForwardScan, process_qualifier, reopenScan, reopenScanByRowLocation, replace, reposition, 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, isTableLocked, reopen, setEstimatedRowCount, setLockingPolicy, test_errors
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface org.apache.derby.iapi.store.access.GenericScanController
isTableLocked
Methods inherited from interface org.apache.derby.iapi.store.access.RowCountable
getEstimatedRowCount, setEstimatedRowCount
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Field Details
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base_cc_for_locking
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Constructor Details
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B2IMaxScan
B2IMaxScan()
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Method Details
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close
Close the scan.- Specified by:
close
in interfaceGenericScanController
- Overrides:
close
in classBTreeScan
- Throws:
StandardException
- Standard exception policy.- See Also:
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closeForEndTransaction
Close the scan, a commit or abort is about to happen.- Specified by:
closeForEndTransaction
in interfaceScanManager
- Overrides:
closeForEndTransaction
in classBTreeScan
- Parameters:
closeHeldScan
- If true, means to close scan even if it has been opened to be kept opened across commit. This is used to close these scans on abort.- Returns:
- boolean indicating that the close has resulted in a real close of the scan. A held scan will return false if called by closeForEndTransaction(false), otherwise it will return true. A non-held scan will always return true.
- Throws:
StandardException
- Standard exception policy.
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init
public void init(TransactionManager xact_manager, Transaction rawtran, int open_mode, int lock_level, LockingPolicy locking_policy, int isolation_level, boolean open_for_locking, FormatableBitSet scanColumnList, B2I conglomerate, B2IUndo undo) throws StandardException Initialize the scan for use.Any changes to this method may have to be reflected in close as well.
The btree init opens the container (super.init), and stores away the state of the qualifiers. The actual searching for the first position is delayed until the first next() call.
- Throws:
StandardException
- Standard exception policy.
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