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
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:
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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
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected 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
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
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
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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Constructor Details
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BTreeForwardScan
public BTreeForwardScan()
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Method Details
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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.
- 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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