Package com.illumon.iris.db.v2.utils

Class RuntimeMemory

java.lang.Object

com.illumon.iris.db.v2.utils.RuntimeMemory

public class RuntimeMemory
extends Object

Cache memory utilization.

Calling Runtime.getRuntime().getFreeMemory() is expensive; and we may do it a lot when we have automatically computed tables, such as in a byExternal. Instead of calling the runtime directly from the performance instrumentation framework, we call this class's methods; which cache the result for a configurable number of milliseconds to avoid repeated calls that are not likely any different.

Additionally, we log our JVM heap usage on a regular basis; to enable users to quickly examine their worker logs and understand memory issues.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	RUNTIME_MEMORY_LOG_INTERVAL_DEFAULT
static final String	RUNTIME_MEMORY_LOG_INTERVAL_PROPERTY

Method Summary

Modifier and Type	Method	Description
long	freeMemory()	See Runtime.freeMemory().
static RuntimeMemory	getInstance()	Return a singleton RuntimeMemory object.
long	getMaxMemory()	See Runtime.maxMemory().
long	totalMemory()	See Runtime.totalMemory().

Methods inherited from class java.lang.Object

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

Field Details

RUNTIME_MEMORY_LOG_INTERVAL_PROPERTY

public static final String RUNTIME_MEMORY_LOG_INTERVAL_PROPERTY

See Also:

• Constant Field Values

RUNTIME_MEMORY_LOG_INTERVAL_DEFAULT

public static final int RUNTIME_MEMORY_LOG_INTERVAL_DEFAULT

See Also:

• Constant Field Values

Method Details

getInstance

public static RuntimeMemory getInstance()

Return a singleton RuntimeMemory object.

Returns:

the RuntimeMemory singleton

freeMemory

public long freeMemory()

See Runtime.freeMemory().

totalMemory

public long totalMemory()

See Runtime.totalMemory().

getMaxMemory

public long getMaxMemory()

See Runtime.maxMemory().