org.apache.derby.impl.store.raw.xact

Class RowLockingRR

java.lang.Object

org.apache.derby.impl.store.raw.xact.NoLocking

org.apache.derby.impl.store.raw.xact.RowLocking3

org.apache.derby.impl.store.raw.xact.RowLockingRR

All Implemented Interfaces:

LockingPolicy

Direct Known Subclasses:

RowLocking2

public class RowLockingRR
extends RowLocking3

A locking policy that implements row level locking with repeatable read isolation. Since phantom protection with previous key locking is actually handled by the upper level access methods, the only difference in repeatable read is that read locks are of type RowLock.RS2. This type will not conflict with a previous key insert lock.

See Also:

LockingPolicy

Field Summary

Fields inherited from class org.apache.derby.impl.store.raw.xact.RowLocking3

lf

Fields inherited from interface org.apache.derby.iapi.store.raw.LockingPolicy

MODE_CONTAINER, MODE_NONE, MODE_RECORD

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RowLockingRR(LockFactory lf)

Method Summary

Modifier and Type	Method and Description
protected RowLock	getReadLockType() Get type of lock to get while reading data.
protected RowLock	getUpdateLockType() Get type of lock to get while requesting "update" lock.
protected RowLock	getWriteLockType() Get type of lock to get while writing data.
void	unlockRecordAfterRead(Transaction t, ContainerHandle container_handle, RecordHandle record, boolean forUpdate, boolean row_qualified) Unlock a record after it has been locked for read.

Methods inherited from class org.apache.derby.impl.store.raw.xact.RowLocking3

getMode, lockContainer, lockRecordForRead, lockRecordForWrite, zeroDurationLockRecordForWrite

Methods inherited from class org.apache.derby.impl.store.raw.xact.NoLocking

unlockContainer

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RowLockingRR

protected RowLockingRR(LockFactory lf)

Method Detail

getReadLockType

protected RowLock getReadLockType()

Description copied from class: RowLocking3

Get type of lock to get while reading data.

This routine is provided so that class's like RowLockingRR can override just this routine to get RS2 locks vs RS3 locks, and still reuse all the other code in this class.

Overrides:

getReadLockType in class RowLocking3

Returns:

The lock type of a shared lock for this locking policy.

getUpdateLockType

protected RowLock getUpdateLockType()

Description copied from class: RowLocking3

Get type of lock to get while requesting "update" lock.

This routine is provided so that class's like RowLockingRR can override just this routine to get RU2 locks vs RU3 locks, and still reuse all the other code in this class.

Overrides:

getUpdateLockType in class RowLocking3

Returns:

The lock type of a shared lock for this locking policy.

getWriteLockType

protected RowLock getWriteLockType()

Description copied from class: RowLocking3

Get type of lock to get while writing data.

This routine is provided so that class's like RowLockingRR can override just this routine to get RX2 locks vs RX3 locks, and still reuse all the other code in this class.

Overrides:

getWriteLockType in class RowLocking3

Returns:

The lock type of a shared lock for this locking policy.

unlockRecordAfterRead

public void unlockRecordAfterRead(Transaction t,
                                  ContainerHandle container_handle,
                                  RecordHandle record,
                                  boolean forUpdate,
                                  boolean row_qualified)
                           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.

Specified by:

unlockRecordAfterRead in interface LockingPolicy

Overrides:

unlockRecordAfterRead in class NoLocking

Throws:

StandardException - Standard exception policy.

See Also:

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