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java.lang.Objectorg.apache.derby.impl.store.access.btree.OpenBTree
org.apache.derby.impl.store.access.btree.BTreeScan
org.apache.derby.impl.store.access.btree.BTreeForwardScan
A b-tree scan controller corresponds to an instance of an open b-tree scan.
Concurrency Notes<\B>
The concurrency rules are derived from OpenBTree.
OpenBTree
Field Summary |
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 |
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 |
Constructor Summary | |
BTreeForwardScan()
|
Method Summary | |
void |
close()
Close the scan. |
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. |
void |
init(TransactionManager xact_manager,
Transaction rawtran,
boolean hold,
int open_mode,
int lock_level,
BTreeLockingPolicy btree_locking_policy,
FormatableBitSet scanColumnList,
DataValueDescriptor[] startKeyValue,
int startSearchOperator,
Qualifier[][] qualifier,
DataValueDescriptor[] stopKeyValue,
int stopSearchOperator,
BTree conglomerate,
LogicalUndo undo,
StaticCompiledOpenConglomInfo static_info,
DynamicCompiledOpenConglomInfo dynamic_info)
Initialize the scan for use. |
protected void |
positionAtStartPosition(BTreeRowPosition pos)
Position scan at "start" position. |
Methods inherited from class org.apache.derby.impl.store.access.btree.BTreeScan |
closeForEndTransaction, delete, didNotQualify, doesCurrentPositionQualify, fetch, fetchLocation, fetchNext, fetchNextGroup, fetchSet, getCurrentRecordHandleForDebugging, getScanInfo, isCurrentPositionDeleted, isKeyed, newRowLocationTemplate, next, positionAtDoneScan, positionAtDoneScanFromClose, positionAtNextPage, positionAtStartForBackwardScan, positionAtStartForForwardScan, process_qualifier, reopenScan, reopenScanByRowLocation, replace, reposition, savePosition, 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, makeRecordHandle, 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 |
Constructor Detail |
public BTreeForwardScan()
Method Detail |
protected void positionAtStartPosition(BTreeRowPosition pos) throws StandardException
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.
positionAtStartPosition
in class BTreeScan
StandardException
- Standard exception policy.public void init(TransactionManager xact_manager, Transaction rawtran, boolean hold, int open_mode, int lock_level, BTreeLockingPolicy btree_locking_policy, FormatableBitSet scanColumnList, DataValueDescriptor[] startKeyValue, int startSearchOperator, Qualifier[][] qualifier, DataValueDescriptor[] stopKeyValue, int stopSearchOperator, BTree conglomerate, LogicalUndo undo, StaticCompiledOpenConglomInfo static_info, DynamicCompiledOpenConglomInfo dynamic_info) throws StandardException
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.
init
in class BTreeScan
StandardException
- Standard exception policy.public void close() throws StandardException
close
in interface GenericScanController
close
in class BTreeScan
StandardException
protected int fetchRows(BTreeRowPosition pos, DataValueDescriptor[][] row_array, RowLocation[] rowloc_array, BackingStoreHashtable hash_table, long max_rowcnt, int[] key_column_numbers) throws StandardException
Utility routine used by both fetchSet() and fetchNextGroup().
fetchRows
in class BTreeScan
StandardException
- Standard exception policy.
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