org.apache.derby.impl.store.access.btree.index
Class B2IRowLockingRR
java.lang.Object
org.apache.derby.impl.store.access.btree.index.B2IRowLocking3
org.apache.derby.impl.store.access.btree.index.B2IRowLockingRR
- All Implemented Interfaces:
- BTreeLockingPolicy
- Direct Known Subclasses:
- B2IRowLocking2
class B2IRowLockingRR
- extends B2IRowLocking3
- implements BTreeLockingPolicy
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
B2IRowLockingRR
B2IRowLockingRR(Transaction rawtran,
int lock_level,
LockingPolicy locking_policy,
ConglomerateController base_cc,
OpenBTree open_btree)
- Constructors for This class:
lockScanRow
public boolean lockScanRow(OpenBTree open_btree,
BTree btree,
BTreeRowPosition pos,
FetchDescriptor lock_fetch_desc,
DataValueDescriptor[] lock_template,
RowLocation lock_row_loc,
boolean previous_key_lock,
boolean forUpdate,
int lock_operation)
throws StandardException
- Lock a row as part of doing the scan.
Lock the row at the given slot (or the previous row if slot is 0).
If this routine returns true all locks were acquired while maintaining
the latch on leaf. If this routine returns false, locks may or may
not have been acquired, and the routine should be called again after
the client has researched the tree to reget the latch on the
appropriate page.
- Specified by:
lockScanRow
in interface BTreeLockingPolicy
- Overrides:
lockScanRow
in class B2IRowLocking3
- Parameters:
open_btree
- The open_btree to associate latches with -
used if routine has to scan backward.btree
- the conglomerate info.pos
- The position of the row to lock.lock_template
- A scratch area to use to read in rows.previous_key_lock
- Is this a previous key lock call?forUpdate
- Is the scan for update or for read only.lock_operation
- For what operation are we requesting the lock,
this should be one of the following 4 options:
LOCK_READ [read lock],
(LOCK_INS | LOCK_UPD) [ lock for insert],
(LOCK_INSERT_PREVKEY | LOCK_UPD) [lock for
previous key to insert],
(LOCK_UPD) [lock for delete or replace]
- Returns:
- Whether locks were acquired without releasing latch on leaf.
- Throws:
StandardException
- Standard exception policy.
unlockScanRecordAfterRead
public void unlockScanRecordAfterRead(BTreeRowPosition pos,
boolean forUpdate)
throws StandardException
- Unlock a record after it has been locked for read.
In repeatable read only unlock records which "did not qualify". For
example in a query like "select * from foo where a = 1" on a table
with no index it is only necessary to hold locks on rows where a=1, but
in the process of finding those rows the system will get locks on other
rows to verify they are committed before applying the qualifier. Those
locks can be released under repeatable read isolation.
if it is forUpdate then get S lock and release U lock, else there is
nothing to do in serializable - we keep the S locks until end of
transaction.
- Specified by:
unlockScanRecordAfterRead
in interface BTreeLockingPolicy
- Overrides:
unlockScanRecordAfterRead
in class B2IRowLocking3
- Parameters:
forUpdate
- Is the scan for update or for read only.pos
- Data structure that defines the current position
in the scan to be unlocked.
- Throws:
StandardException
- Standard exception policy.
Apache Derby V10.6 Internals - Copyright © 2004,2007 The Apache Software Foundation. All Rights Reserved.