Connections Manipulator

Connections Manipulator runs only on the dispatcher nodes of the cluster because its function is client connection management. It supports TCP and UDP connections.

Connections Manipulator runs in the follwoing modes:

Mode 1 – each client connection is associated with one thread in the Thread Manager. Each thread is blocked for linear calculated socket timeout, which specifies the time the thread the connection is associated with sleeps. When there is just one connection, this socket timeout is the maximum. When the number of connections increases to reach the maximum for this mode, socket timeout decreases linearly to reach its lowest value with the maximum number of connections.
Mode 2 – this is used when the number of connections exceeds the maximum for Mode 1. Each connection is not associated with just one thread, but each thread processes a number of connections.
Mode 3 – this is the so-called busy read in which the number of connections exceeds the maximum number of connections in Mode 2. The system administrator cannot set any properties for this mode.

Connections Manipulator supports both TCP and UDP connections. These two kinds of connection objects are stored in separate pools. The properties of these pools can be set by the system administrator.

Visual Administrator

Properties

	Dispatcher
Property	Description	Default Value

MaxSoTimeOutConnections	Specifies the maximum number of connections for Mode 1.	100
MaxThreadRepeatCount	Specifies the maximum number of connections each thread can process.	700
MaxRepeatConnections	Specifies the maximum number of connections for Mode 2.	3500
MinSoTimeOut	Specifies the minimum value of socket timeout in milliseconds.	1000
MaxSoTimeOut	Specifies the maximum value of socket timeout in milliseconds.	30000
TCPMinPoolSize	Specifies the minimum size of the pool for TCP connections.	100
TCPMaxPoolSize	Specifies the maximum size of the pool for TCP connections.	500
TCPIncreasePoolSize	Specifies the step value at which the pool for TCP connections is changed.	50
UDPMinPoolSize	Specifies the minimum size of the pool for UDP connections.	100
UDPMaxPoolSize	Specifies the maximum size of the pool for UDP connections.	500
UDPIncreasePoolSize	Specifies the step value at which the pool for UDP connections is changed.	50

Property Files

../cluster/dispatcher/managers/settings/ConnectionsManipulator.properties
Connections Manipulator properties specified in the Visual Administrator section can be set from this property file as well.

Critical Information and Troubleshooting Tips

When setting the Connections Manipulator properties, two key factors must be taken into consideration: the communication protocols used by the clients that connect, and the frequency of requests. These settings are specific for each particular situation, and it is up to the system administrator to configure them to achieve the optimal solution.

When Connections Manipulator is running in Mode 1, the system administrator must pay attention to the maxSoTimeOutConnections property setting. As it uses Thread Manager, and each connection is associated with one thread, the maximum number of connections must be approximately equal to the number of threads in Thread Manager. Otherwise, performance deteriorates severely.