org.tentackle.db
Class MpxConnectionManager

java.lang.Object
  org.tentackle.db.DefaultConnectionManager
      org.tentackle.db.MpxConnectionManager

All Implemented Interfaces:

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

Field Summary

protected int	incSize
protected int	maxMinutes
protected int	maxSize
protected int	minMinutes
protected int	minSize
protected Random	random
protected Db	serverDb
protected int	unConCount
protected int[]	unConList

Fields inherited from class org.tentackle.db.DefaultConnectionManager

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

Constructor Summary

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

ManagedConnection	attach(int id) 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(int id) Detaches a connection from a Db. A Db must be detached to release the connection for use of other Db instances.
int	login(Db db) Logs in a Db connection. It is up to the manager how to verify whether the Db is allowed to open, a real connection is initiated or just an application level authorization is performed.
Db	logout(int id) Logs out a Db connection.
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	shutdown() Shuts down this connection manager. All connections are closed and the threads stopped.

Methods inherited from class org.tentackle.db.DefaultConnectionManager

addConnection, addDb, getConnectionCount, getDbCount, getMaxConnections, getMaxCountForClearWarnings, getMaxLogins, removeConnection, removeDb, setMaxCountForClearWarnings, toString

Methods inherited from class java.lang.Object

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

Field Detail

serverDb

protected Db serverDb

incSize

protected int incSize

minSize

protected int minSize

maxSize

protected int maxSize

minMinutes

protected int minMinutes

maxMinutes

protected int maxMinutes

unConList

protected int[] unConList

unConCount

protected int unConCount

random

protected Random random

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 ConnectionManager

Overrides:

shutdown in class DefaultConnectionManager

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(Db db)
          throws DbRuntimeException

Description copied from interface: ConnectionManager

Logs in a Db connection.
It is up to the manager how to verify whether the Db is allowed to open, a real connection is initiated or just an application level authorization is performed. Note that the ID may be recycled by the manager after a Db is logged out.

Specified by:

login in interface ConnectionManager

Overrides:

login in class DefaultConnectionManager

Parameters:

db - the db to login

Returns:

the connection ID of the db (> 0)

Throws:

DbRuntimeException - if login failed.

logout

public Db logout(int id)
          throws DbRuntimeException

Description copied from interface: ConnectionManager

Logs out a Db connection. The Db is not allowed to attach anymore. If the Db is still attached, a rollback of any pending tx is done and an exception thrown.

Specified by:

logout in interface ConnectionManager

Overrides:

logout in class DefaultConnectionManager

Parameters:

id - the connection ID of the db

Returns:

the logged out Db

Throws:

DbRuntimeException - if logout failed.

attach

public ManagedConnection attach(int id)
                         throws DbRuntimeException

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.

Specified by:

attach in interface ConnectionManager

Overrides:

attach in class DefaultConnectionManager

Parameters:

id - the connection ID of the db

Returns:

the connection attached to be used by subsequent operations

Throws:

DbRuntimeException - if attach failed.

detach

public void detach(int id)
            throws DbRuntimeException

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:

id - the connection ID of the db

Throws:

DbRuntimeException - if detach failed.