org.apache.derby.impl.store.access.btree

Class OpenBTree

java.lang.Object

org.apache.derby.impl.store.access.btree.OpenBTree

Direct Known Subclasses:

BTreeController, BTreeCostController, BTreeScan

public class OpenBTree
extends java.lang.Object

An open b-tree contains fields and methods common to scans and controllers.

Concurrency Notes

An instance of an open b-tree is owned by a single context. The b-tree code assumes that the context ensures that only one thread at a time is using the open b-tree. The open b-tree itself does not enforce or check this.

Constructor Summary

Constructors

Constructor and Description
OpenBTree()

Method Summary

Modifier and Type	Method and Description
void	checkConsistency() Check consistency of a btree.
void	close() Close the open conglomerate.
void	debugConglomerate() Dump information about tree into the log.
boolean[]	getColumnSortOrderInfo()
BTree	getConglomerate()
ContainerHandle	getContainer()
ContainerHandle	getContainerHandle() Return the container handle.
long	getEstimatedRowCount() Get the total estimated number of rows in the container.
int	getHeight() get height of the tree.
boolean	getHold()
BTreeLockingPolicy	getLockingPolicy()
int	getLockLevel()
int	getOpenMode()
Transaction	getRawTran()
OpenConglomerateScratchSpace	getRuntimeMem()
SpaceInfo	getSpaceInfo()
TransactionManager	getXactMgr() Public Accessors of This class:
void	init(TransactionManager open_user_scans, TransactionManager xact_manager, ContainerHandle input_container, Transaction rawtran, boolean hold, int open_mode, int lock_level, BTreeLockingPolicy btree_locking_policy, BTree conglomerate, LogicalUndo undo, DynamicCompiledOpenConglomInfo dynamic_info) Initialize the open conglomerate.
boolean	isClosed()
boolean	isTableLocked() is the open btree table locked?
ContainerHandle	reopen() Open the container after it has been closed previously.
void	setEstimatedRowCount(long count) Set the total estimated number of rows in the container.
void	setLockingPolicy(BTreeLockingPolicy policy)
static boolean	test_errors(OpenBTree open_btree, java.lang.String debug_string, BTreeRowPosition pos, BTreeLockingPolicy btree_locking_policy, LeafControlRow leaf, boolean input_latch_released) Testing infrastructure to cause unusual paths through the code.

Methods inherited from class java.lang.Object

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

Constructor Detail

OpenBTree

public OpenBTree()

Method Detail

getXactMgr

public final TransactionManager getXactMgr()

Public Accessors of This class:

getRawTran

public final Transaction getRawTran()

getLockLevel

public final int getLockLevel()

getContainer

public final ContainerHandle getContainer()

getOpenMode

public final int getOpenMode()

getConglomerate

public final BTree getConglomerate()

getHold

public final boolean getHold()

getLockingPolicy

public final BTreeLockingPolicy getLockingPolicy()

setLockingPolicy

public final void setLockingPolicy(BTreeLockingPolicy policy)

isClosed

public final boolean isClosed()

getRuntimeMem

public final OpenConglomerateScratchSpace getRuntimeMem()

getEstimatedRowCount

public long getEstimatedRowCount()
                          throws StandardException

Get the total estimated number of rows in the container.

The number is a rough estimate and may be grossly off. In general the server will cache the row count and then occasionally write the count unlogged to a backing store. If the system happens to shutdown before the store gets a chance to update the row count it may wander from reality.

This call is currently only supported on Heap conglomerates, it will throw an exception if called on btree conglomerates.

Returns:

The total estimated number of rows in the conglomerate.

Throws:

StandardException - Standard exception policy.

setEstimatedRowCount

public void setEstimatedRowCount(long count)
                          throws StandardException

Set the total estimated number of rows in the container.

Often, after a scan, the client of RawStore has a much better estimate of the number of rows in the container than what store has. For instance if we implement some sort of update statistics command, or just after a create index a complete scan will have been done of the table. In this case this interface allows the client to set the estimated row count for the container, and store will use that number for all future references.

This call is currently only supported on Heap conglomerates, it will throw an exception if called on btree conglomerates.

Parameters:

count - the estimated number of rows in the container.

Throws:

StandardException - Standard exception policy.

checkConsistency

public void checkConsistency()
                      throws StandardException

Check consistency of a btree.

Read in root and check consistency of entire tree. Currently raises sanity check errors.

RESOLVE (mikem) if this is to be supported in non-sanity servers what should it do?

Throws:

StandardException - Standard exception policy.

isTableLocked

public boolean isTableLocked()

is the open btree table locked?

init

public void init(TransactionManager open_user_scans,
                 TransactionManager xact_manager,
                 ContainerHandle input_container,
                 Transaction rawtran,
                 boolean hold,
                 int open_mode,
                 int lock_level,
                 BTreeLockingPolicy btree_locking_policy,
                 BTree conglomerate,
                 LogicalUndo undo,
                 DynamicCompiledOpenConglomInfo dynamic_info)
          throws StandardException

Initialize the open conglomerate.

If container is null, open the container, otherwise use the container passed in. The container is always opened with no locking, it is up to the caller to make the appropriate container locking call.

Parameters:

open_user_scans - The user transaction which opened this btree.

xact_manager - The current transaction, usually the same as "open_user_scans", but in the case of split it is the internal xact nested below the user xact.

input_container - The open container holding the index, if it is already open, else null which will mean this routine will open it.

rawtran - The current raw store transaction.

open_mode - The opening mode for the ContainerHandle.

conglomerate - Readonly description of the conglomerate.

undo - Logical undo object to associate with all updates done on this open btree.

Throws:

StandardException - Standard exception policy.

reopen

public ContainerHandle reopen()
                       throws StandardException

Open the container after it has been closed previously.

Open the container, obtaining necessary locks. Most work is actually done by RawStore.openContainer(). Will only reopen() if the container is not already open.

Throws:

StandardException - Standard exception policy.

close

public void close()
           throws StandardException

Close the open conglomerate.

Throws:

StandardException

getContainerHandle

public ContainerHandle getContainerHandle()

Return the container handle.

Returns:

The open container handle of the btree.

getHeight

public int getHeight()
              throws StandardException

get height of the tree.

Read in root and return the height (number of levels) of the tree. The level of a tree is 0 in the leaf and increases by 1 for each level of the tree as you go up the tree.

Throws:

StandardException - Standard exception policy.

debugConglomerate

public void debugConglomerate()
                       throws StandardException

Dump information about tree into the log.

Traverse the tree dumping info about tree into the log.

Throws:

StandardException - Standard exception policy.

test_errors

public static boolean test_errors(OpenBTree open_btree,
                                  java.lang.String debug_string,
                                  BTreeRowPosition pos,
                                  BTreeLockingPolicy btree_locking_policy,
                                  LeafControlRow leaf,
                                  boolean input_latch_released)
                           throws StandardException

Testing infrastructure to cause unusual paths through the code.

Through the use of debug flags allow test code to cause otherwise hard to cause paths through the code.

Parameters:

pos - the current scan position if the condition simulated by this call would have resulted in the position being saved

Returns:

whether the latch has been released by this routine.

Throws:

StandardException - Standard exception policy.

getSpaceInfo

public SpaceInfo getSpaceInfo()
                       throws StandardException

Throws:

StandardException

getColumnSortOrderInfo

public boolean[] getColumnSortOrderInfo()
                                 throws StandardException

Throws:

StandardException