Memory Manager

Memory Manager stores information about the level of memory usage in SAP J2EE Engine 6.20. Memory is divided into five levels that specify the part used. SAP J2EE Engine 6.20 Managers and Services obtain this information using registered listeners to Memory Manager. It runs on both dispatcher and server nodes.

Visual Administrator

Properties

	Dispatcher
Property	Description	Default Value

MaxMemory	Specifies the amount of memory that the Java Virtual Machine (JVM) can use (in MB). The administrator can increase its default value, depending on the physical machine configuration. It is recommended that the default value be at least 20 MB.	64
MemoryLevels	Defines the upper limits of memory usage (in per cent) as memory levels. They are five in number and each one is of `byte` type. The values are in ascending order and the last value is less than 100. Integer values are required. When the memory usage passes from one level to another, this event is denoted using the NoticeLogFileName property of Log Manager.	{50,65,75,80,81}
SleepTimes	Defines the time limits (in milliseconds), after which Memory Manager checks the status of memory. The values are in descending order and of `long` type in Java.	{3200,1600,800,400,200,100}
ErrorLogFileName	Specifies the filename to which error log messages are written.	./managers/log /ERROR.log
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
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
InfoLogFileName	Specifies the filename to which info log messages for Memory Manager are written.	./managers/log /memory/INFO.log
CriticalLogFileName	Specifies the filename to which critical log messages are written.	./managers/log /CRITICAL.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
AlertLogFileName	Specifies the filename to which alert log messages are written.	./managers/log /ALERT.log
EmergencyLogFileName	Specifies the filename to which emergency log messages are written.	./managers/log /EMERGENCY.log
DebugLogFileName	Specifies the filename to which debug log messages for Memory Manager are written.	./managers/log /memory/DEBUG.log
NoticeLogFileName	Specifies the filename to which notice log messages for Memory Manager are written.	./managers/log /memory/NOTICE.log
WarningLogFileName	Specifies the filename to which warning log messages for Memory Manager are written.	./managers/log /memory/WARNING.log

	Server
Property	Description	Default Value

MaxMemory	Specifies the amount of memory that JVM can use (in MB). The administrator can increase its default value, depending on the physical machine configuration. It is recommended that the default value be at least 20 MB.	64
MemoryLevels	This property defines the upper limits of memory usage (in per cent) as memory levels. There are five values and each one is of `byte` type. The values are in ascending order and the last value is less than 100. Integer values are required. When the memory usage passes from one level to another, this event is denoted using the NoticeLogFileName property of Log Manger.	{50,65,75,80,81}
SleepTimes	This property defines the time limits (in milliseconds), after which Memory Manager checks the status of memory. The values are in descending order and of `long` type in Java.	{3200,1600,800,400,200,100}
ErrorLogFileName	Specifies the filename to which error log messages are written.	./managers/log /ERROR.log
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
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
InfoLogFileName	Specifies the filename to which info log messages for Memory Manager are written.	./managers/log /memory/INFO.log
CriticalLogFileName	Specifies the filename to which critical log messages are written.	./managers/log /CRITICAL.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
AlertLogFileName	Specifies the filename to which alert log messages are written.	./managers/log /ALERT.log
EmergencyLogFileName	Specifies the filename to which emergency log messages are written.	./managers/log /EMERGENCY.log
DebugLogFileName	Specifies the filename to which debug log messages for Memory Manager are written.	./managers/log /memory/DEBUG.log
NoticeLogFileName	Specifies the filename to which notice log messages for Memory Manager are written.	./managers/log /memory/NOTICE.log
WarningLogFileName	Specifies the filename to which warning log messages for Memory Manager are written.	./managers/log /memory/WARNING.log

Property Files

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

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

Critical Information and Troubleshooting Tips

The system administrator must be careful when setting the MaxMemory property. Typically, its value must never exceed the maximum value of physical machine operating memory. In addition, if the value is set below 20MB, it is critical that not all of the core services are loaded and a timeout is caused. The server will not load correctly. Therefore, the recommended memory value is 64MB, which provides for all services loading successfully, and available additional memory. Optionally, the system administrator may choose to change the limits of memory levels. This property can be reconfigured so that unused objects are more frequently removed, thereby ensuring the JVM does not run out of memory.