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.

Method Summary

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

Methods inherited from class java.lang.Object

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

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().