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

Class RowLocking3Escalate

java.lang.Object

org.apache.derby.impl.store.raw.xact.ContainerLocking3

org.apache.derby.impl.store.raw.xact.RowLocking3Escalate

All Implemented Interfaces:

LockingPolicy

public class RowLocking3Escalate
extends ContainerLocking3

A locking policy that implements row level locking with isolation degree 3.

See Also:

LockingPolicy

Field Summary

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

MODE_CONTAINER, MODE_NONE, MODE_RECORD

Method Summary

Modifier and Type	Method and Description
boolean	lockContainer(Transaction t, ContainerHandle container, boolean waitForLock, boolean forUpdate) Escalates Row Locking 3 to Container Locking 3.
boolean	lockRecordForRead(Transaction t, ContainerHandle container, RecordHandle record, boolean waitForLock, boolean forUpdate) Called before a record is fetched.
boolean	lockRecordForWrite(Transaction t, RecordHandle record, boolean lockForInsert, boolean waitForLock) Called before a record is inserted, updated or deleted.
void	unlockContainer(Transaction t, ContainerHandle container) Called when a container is closed.
void	unlockRecordAfterRead(Transaction t, ContainerHandle container, RecordHandle record, boolean forUpdate, boolean row_qualified) Called after a record has been fetched.
boolean	zeroDurationLockRecordForWrite(Transaction t, RecordHandle record, boolean lockForPreviousKey, boolean waitForLock) Request a write lock which will be released immediately upon grant.

Methods inherited from class org.apache.derby.impl.store.raw.xact.ContainerLocking3

getMode

Methods inherited from class java.lang.Object

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

Method Detail

lockContainer

public boolean lockContainer(Transaction t,
                             ContainerHandle container,
                             boolean waitForLock,
                             boolean forUpdate)
                      throws StandardException

Escalates Row Locking 3 to Container Locking 3.

This call is made by code which tracks the number of locks on a container. When the number of locks exceeds the escalate threshold the caller creates this new locking policy, calls lockContainer(), and substitues it for the old locking policy. The lockContainer call determines which table lock to get (S or X), gets that table lock, and then releases the row locks on the table. It is assumed that this is called on a open container for lock only.

Specified by:

lockContainer in interface LockingPolicy

Overrides:

lockContainer in class ContainerLocking3

Parameters:

t - Transaction to associate lock with.

container - Container to lock.

waitForLock - Ignored - will never wait for a lock.

forUpdate - Ignored, mode determined from current lock state.

Returns:

true if the lock was obtained, false if it wasn't. False should only be returned if the waitForLock policy was set to "false," and the lock was unavailable.

Throws:

StandardException - Standard exception policy.

See Also:

ContainerHandle

unlockContainer

public void unlockContainer(Transaction t,
                            ContainerHandle container)

Description copied from interface: LockingPolicy

Called when a container is closed.

Specified by:

unlockContainer in interface LockingPolicy

See Also:

ContainerHandle, ContainerHandle.close()

lockRecordForRead

public boolean lockRecordForRead(Transaction t,
                                 ContainerHandle container,
                                 RecordHandle record,
                                 boolean waitForLock,
                                 boolean forUpdate)
                          throws StandardException

Description copied from interface: LockingPolicy

Called before a record is fetched.

Specified by:

lockRecordForRead in interface LockingPolicy

Parameters:

t - Transaction to associate lock with.

container - Open Container used to get record. Will be used to row locks by the container they belong to.

record - Record to lock.

waitForLock - Should lock request wait until granted?

forUpdate - Should container be locked for update, or read?

Throws:

StandardException - Standard Derby error policy

See Also:

Page

zeroDurationLockRecordForWrite

public boolean zeroDurationLockRecordForWrite(Transaction t,
                                              RecordHandle record,
                                              boolean lockForPreviousKey,
                                              boolean waitForLock)
                                       throws StandardException

Description copied from interface: LockingPolicy

Request a write lock which will be released immediately upon grant.

Specified by:

zeroDurationLockRecordForWrite in interface LockingPolicy

Parameters:

t - Transaction to associate lock with.

record - Record to lock.

lockForPreviousKey - Lock is for a previous key of a insert.

waitForLock - Should lock request wait until granted?

Returns:

true if the lock was obtained, false if it wasn't. False should only be returned if the waitForLock argument was set to "false," and the lock was unavailable.

Throws:

StandardException - Standard Derby error policy

See Also:

Page

lockRecordForWrite

public boolean lockRecordForWrite(Transaction t,
                                  RecordHandle record,
                                  boolean lockForInsert,
                                  boolean waitForLock)
                           throws StandardException

Description copied from interface: LockingPolicy

Called before a record is inserted, updated or deleted. If zeroDuration is true then lock is released immediately after it has been granted.

Specified by:

lockRecordForWrite in interface LockingPolicy

Parameters:

t - Transaction to associate lock with.

record - Record to lock.

lockForInsert - Lock is for an insert.

waitForLock - Should lock request wait until granted?

Returns:

true if the lock was obtained, false if it wasn't. False should only be returned if the waitForLock argument was set to "false," and the lock was unavailable.

Throws:

StandardException - Standard Derby error policy

See Also:

Page

unlockRecordAfterRead

public void unlockRecordAfterRead(Transaction t,
                                  ContainerHandle container,
                                  RecordHandle record,
                                  boolean forUpdate,
                                  boolean row_qualified)
                           throws StandardException

Description copied from interface: LockingPolicy

Called after a record has been fetched.

Specified by:

unlockRecordAfterRead in interface LockingPolicy

Throws:

StandardException - Standard Derby error policy

See Also:

Page