Thread Manager

Thread Manager starts and manages client threads in the Java Virtual Machine. It saves system resources by controlling the number of threads at a particular moment and the way they are started. Thread Manager enables you to reuse threads, which it keeps in a pool. This manager runs on both server and dispatcher nodes of the cluster.

When initializing Thread Manager the following types of structures are created:

A thread pool for execution of registered threads
A queue that holds registered threads
A pool of inner reusable objects that participate in the queue

Objects registered for execution in a thread are assigned with priorities.

Visual Administrator

Properties

	Dispatcher
Property	Description	Default Value

InitialThreadCount	Initial size of thread pool.	100
CurrentThreadCount	Current size of thread pool.	100
MinThreadCount	Minimum size of thread pool.	50
MaxThreadCount	Maximum size of thread pool.	200
ChangeThreadCountStep	The step width, which is used to change the size of the thread pool.	100
InitialRQSize	Initial size of waiting objects queue.	100
MinRQSize	Minimum size of waiting objects queue.	100
MaxRQSize	Maximum size of waiting objects queue.	200
ChangeRQSizeStep	The step at which the size of the queue is changed.	50
CheckForDecreaseTimeout	Specifies the period between checks performed on Thread Manager to determine if the current number of threads must be decreased to avoid nonworking threads and to release memory. When thread count grows, check time must decrease.	3 min
NeededPositiveDecreaseChecks	Specifies the number of consecutive checks returned as “true,” after which the number of threads is decreased.	3
AlertLogFileName	Specifies the filename to which alert log messages are written.	./managers/log /ALERT.log
NormalLogFileName	This parameter specifies the filename to which messages with normal priority are written. This file is used by the Log viewer of the system to display the messages.	DEFAULT.log
WarningLogFileName	Specifies the filename to which warning log messages for Thread Manager are written.	./managers/log /thread/WARNING.log
CriticalLogFileName	Specifies the filename to which critical log messages are written.	./managers/log /CRITICAL.log
ErrorLogFileName	Specifies the filename to which error log messages are written.	./managers/log /ERROR.log
NoticeLogFileName	Specifies the filename to which notice log messages for Thread Manager are written.	./managers/log /thread/NOTICE.log
NormalLogLevel	Specifies the types of log messages that have normal priority. It is a number from 0 to 7 specifying that log messages within [0, NormalLogLevel] are written in the DefaultNormalFile.	5
CriticalLogLevel	Specifies the types of log messages that have critical priority. It is a number from 0 to 7 specifying that log messages within [CriticalLogLevel,7] are written in the DefaultCriticalFile.	3
EmergencyLogFileName	Specifies the filename to which emergency log messages are written.	./managers/log /EMERGENCY.log
InfoLogFileName	Specifies the filename to which info log messages for Thread Manager are written.	./managers/log /thread/INFO.log
DebugLogFileName	Specifies the filename to which debug log messages for Thread Manager are written.	./managers/log /thread/DEBUG.log

	Server
Property	Description	Default Value

InitialThreadCount	Initial size of thread pool.	40
CurrentThreadCount	Current size of thread pool.	40
MinThreadCount	Minimum size of thread pool.	40
MaxThreadCount	Maximum size of thread pool.	40
ChangeThreadCountStep	The step at which the size of the thread pool is changed.	100
InitialRQSize	Initial size of waiting objects queue.	500
MinRQSize	Minimum size of waiting objects queue.	100
MaxRQSize	Maximum size of waiting objects queue.	6000
ChangeRQSizeStep	The step at which the size of the queue is changed.	100
InitialFOQSize	This value specifies the initial size of the pool of inner objects. These objects are referred to as reusable objects.	200
MinFOQSize	Minimum size of the pool with reusable objects.	100
MaxFOQSize	Maximum size of the pool with reusable objects.	5000
ChangeFOQSizeStep	The step at which the size of the pool with reusable objects is changed.	100
CheckForDecreaseTimeout	Specifies period between checks performed on Thread Manager to determine if the current number of threads must be decreased to avoid nonworking threads and to release memory. When thread count grows, check time must decrease.	3 min
NeededPositiveDecreaseChecks	Specifies the number of consecutive checks returned as “true,” after which the number of threads is decreased.	3
AlertLogFileName	Specifies the filename to which alert log messages are written.	./managers/log /ALERT.log
NormalLogFileName	This parameter specifies the filename to which messages with normal priority are written. This file is used by the Log viewer of the system to display the messages.	DEFAULT.log
WarningLogFileName	Specifies the filename to which warning log messages for Thread Manager are written.	./managers/log /thread/WARNING.log
CriticalLogFileName	Specifies the filename to which critical log messages are written.	./managers/log /CRITICAL.log
ErrorLogFileName	Specifies the filename to which error log messages are written.	./managers/log /ERROR.log
NoticeLogFileName	Specifies the filename to which notice log messages for Thread Manager are written.	./managers/log /thread/NOTICE.log
NormalLogLevel	Specifies the types of log messages that have normal priority. It is a number from 0 to 7 specifying that log messages within [0,NormalLogLevel] are written in the DefaultNormalFile.	5
CriticalLogLevel	Specifies the types of log messages that have critical priority. It is a number from 0 to 7 specifying that log messages within [CriticalLogLevel,7] are written in the DefaultCriticalFile.	3
EmergencyLogFileName	Specifies the filename to which emergency log messages are written.	./managers/log /EMERGENCY.log
InfoLogFileName	Specifies the filename to which info log messages for Thread Manager are written.	./managers/log /thread/INFO.log
DebugLogFileName	Specifies the filename to which debug log messages for Thread Manager are written.	./managers/log /thread/DEBUG.log

Property Files

../cluster/dispatcher/managers/settings/ThreadManager.properties
Thread Manager properties specified in the Visual Administrator section can be set from this property file as well.

../cluster/server/managers/settings/ThreadManager.properties
Thread Manager properties specified in the Visual Administrator section can be set from this property file as well.

Critical Information and Troubleshooting Tips

When setting the minimum and maximum number of threads to be started (MinThreadCount and MaxThreadCount properties), the capacity of the operating system used must be considered carefully. There is no point in assigning MaxThreadCount a value greater than the number of threads the operating system allows to be started. Performance may be improved as the size of the queue of waiting objects is increased; however, this must be done only if enough memory resources are available. Do not overload the virtual machine. When check time for the current threads status is below the default value (three minutes) frequent verifications can slow down the execution of system processes.