org.tentackle.persist

Class MpxConnectionManager

java.lang.Object

java.lang.Thread

org.tentackle.persist.DefaultConnectionManager

org.tentackle.persist.MpxConnectionManager

All Implemented Interfaces:

Runnable, SessionManager, ConnectionManager

public class MpxConnectionManager
extends DefaultConnectionManager

Multiplexing connection manager.
A connection manager for applications with a large number of Db instances, e.g. application servers. The manager will multiplex N Db instances against M connections, allowing N > M. This is not to be mixed up with db-pooling, as connection multiplexing is completely transparent to the application whereas pooling requires an explicit relation to something like a session. Note that the authentication must be done at the application level because the pool's connections are derived from the userinfo of a server db.

Author:

harald

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields

Modifier and Type	Field and Description
protected int	incSize increment size.
protected boolean	initialized true if initialized.
protected int	maxMinutes max hours to close connections.
protected int	minMinutes min hours to close connections.
protected int	minSize minimum size.
protected Random	random randomizer.
protected Db	serverDb server Db to clone.
protected int	unConCount number of entries in unConList.
protected int[]	unConList free list for unattached connections.

Fields inherited from class org.tentackle.persist.DefaultConnectionManager

conList, dbSize, freeConCount, freeConList, freeDbCount, freeDbList, idOffset, iniSize, maxConSize, maxDbSize, name

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor and Description
MpxConnectionManager(Db serverDb) Creates a connection manager with reasonable values for most servers.
MpxConnectionManager(String name, Db serverDb, int maxDb, int idOffset, int iniSize, int incSize, int minSize, int maxSize, int minMinutes, int maxMinutes) Creates a new connection manager.

Method Summary

Modifier and Type	Method and Description
void	attach(Session session) Attaches a Db to a connection. A Db must be attached before it can use any statements.
protected int	createConnections(int count) Create spare connections.
void	detach(Session session) Detaches a connection from a Db. A Db must be detached to release the connection for use of other Db instances.
void	forceDetach(Session session) Detaches but also scans for pending statements to cleanup.
int	getInfoLogSize() Gets the number of connections when to start info logging.
int	getWarnLogSize() Gets the number of connections when to start warning logging.
int	login(Session session)
void	logout(Session session)
protected int	popUnattached() Gets a connection from the unattached freelist.
protected void	pushUnattached(int index) Adds the index of an unused connection to the freelist.
void	setInfoLogSize(int infoLogSize) Sets the number of connections when to start info logging.
void	setWarnLogSize(int warnLogSize) Sets the number of connections when to start warning logging.
void	shutdown() Shuts down this connection manager. All connections are closed and the threads stopped.

Methods inherited from class org.tentackle.persist.DefaultConnectionManager

addConnection, addDb, assertSessionBelongsToMe, convertConnectionIdToIndex, getAttachTimeout, getConnectionCount, getConnections, getMaxConnections, getMaxCountForClearWarnings, getMaxSessions, getNumConnections, getNumSessions, removeConnection, removeDb, run, setAttachTimeout, setMaxCountForClearWarnings, toString

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, yield

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.tentackle.pdo.SessionManager

getName

Field Detail

serverDb

protected final Db serverDb

server Db to clone.

incSize

protected final int incSize

increment size.

minSize

protected final int minSize

minimum size.

minMinutes

protected final int minMinutes

min hours to close connections.

maxMinutes

protected final int maxMinutes

max hours to close connections.

unConList

protected int[] unConList

free list for unattached connections.

unConCount

protected int unConCount

number of entries in unConList.

random

protected Random random

randomizer.

initialized

protected boolean initialized

true if initialized.

Constructor Detail

MpxConnectionManager

public MpxConnectionManager(String name,
                            Db serverDb,
                            int maxDb,
                            int idOffset,
                            int iniSize,
                            int incSize,
                            int minSize,
                            int maxSize,
                            int minMinutes,
                            int maxMinutes)

Creates a new connection manager.

Parameters:

name - the name of the connection manager

serverDb - the root db to use for creating connections (may be open or closed)

maxDb - the maximum number of Db instances, 0 = no limit

idOffset - the offset for connection ids (> 0)

iniSize - the initial size of the connection pool

incSize - the number of connections to add if all in use

minSize - the minimum number of connections

maxSize - the maximum number of connections

minMinutes - minimum minutes a connection should be used

maxMinutes - maximum minutes a connection should be used

MpxConnectionManager

public MpxConnectionManager(Db serverDb)

Creates a connection manager with reasonable values for most servers. Maximum of 1000 Db instances (500 clients). Start with 8 connections. Add 2 connections at a time if all connections are in use. Don't drop below 4 connections. Maximum of 100 connections, i.e. concurrent db operations (i.e. info above 25, warning above 50) Within 12 to 36h (approx. once a day), close and reopen connections (allows updates of the database servers's QEPs, prepared statements cache, etc...). The idOffset will be the connectionId of the serverDb + 1 (i.e. normally 2 for application servers)

Parameters:

serverDb - the root db to use for creating connections (may be open or closed).

Method Detail

shutdown

public void shutdown()

Shuts down this connection manager.
All connections are closed and the threads stopped. Application servers should invoke this method when shut down.

Specified by:

shutdown in interface SessionManager

Overrides:

shutdown in class DefaultConnectionManager

getInfoLogSize

public int getInfoLogSize()

Gets the number of connections when to start info logging.

The default is 1/4th of the maximum number of connections.

Returns:

the info level

setInfoLogSize

public void setInfoLogSize(int infoLogSize)

Sets the number of connections when to start info logging.

Parameters:

infoLogSize - the info level

getWarnLogSize

public int getWarnLogSize()

Gets the number of connections when to start warning logging.

The default is half of the maximum number of connections.

Returns:

the warning level

setWarnLogSize

public void setWarnLogSize(int warnLogSize)

Sets the number of connections when to start warning logging.

Parameters:

warnLogSize - the warning level

pushUnattached

protected void pushUnattached(int index)

Adds the index of an unused connection to the freelist.

Parameters:

index - the index of the connection in the connections list

popUnattached

protected int popUnattached()

Gets a connection from the unattached freelist.

Returns:

the index to the connections list, -1 if no more unattached found

createConnections

protected int createConnections(int count)

Create spare connections.

Parameters:

count - the number of connections to create

Returns:

the number of connections created

login

public int login(Session session)

Specified by:

login in interface SessionManager

Overrides:

login in class DefaultConnectionManager

logout

public void logout(Session session)

Specified by:

logout in interface SessionManager

Overrides:

logout in class DefaultConnectionManager

attach

public void attach(Session session)

Description copied from interface: ConnectionManager

Attaches a Db to a connection.
A Db must be attached before it can use any statements. The framework will attach at the begining of a transaction or when getting a prepared statement or when getting a one-shot non-prepared statement. Note that attachments can be nested to any depth, i.e. only the first attach really binds the connection to the Db.

Upon return the the session will reference the connection.

Specified by:

attach in interface ConnectionManager

Overrides:

attach in class DefaultConnectionManager

Parameters:

session - the session

detach

public void detach(Session session)

Description copied from interface: ConnectionManager

Detaches a connection from a Db.
A Db must be detached to release the connection for use of other Db instances. The framework will detach the db on every commit or rollback, after executeUpdate or after a resultset is closed for an executeQuery. Note that attachments can be nested to any depth, i.e. only the last detach really unbinds the connection from the Db.

Specified by:

detach in interface ConnectionManager

Overrides:

detach in class DefaultConnectionManager

Parameters:

session - the session

forceDetach

public void forceDetach(Session session)

Description copied from interface: ConnectionManager

Detaches but also scans for pending statements to cleanup.

This will detach at any nesting level!

Specified by:

forceDetach in interface ConnectionManager

Overrides:

forceDetach in class DefaultConnectionManager

Parameters:

session - the session