Class MemoryMonitor

java.lang.Object
org.infinispan.commons.util.MemoryMonitor
public class MemoryMonitor extends Object
Monitors JVM memory usage and garbage collection activity, raising alerts when configurable thresholds are exceeded.

Two types of conditions are tracked:

  • Memory threshold — alerts when old generation heap usage exceeds a configured fraction of the maximum heap. The alert auto-clears after a GC if usage drops back below the threshold. Requires a JVM that exposes an old generation memory pool with usage threshold support. All collectors on JDK 25+ are supported; on older JDKs, ZGC and non-generational Shenandoah may lack this, in which case the monitor is automatically disabled and a warning is logged.
  • GC pressure — alerts when the ratio of time spent in GC over a rolling window exceeds a configured fraction. Auto-clears when pressure drops below the threshold.

Individual GC pauses exceeding the duration threshold are logged as warnings but do not raise a persistent alert.

All thresholds are mutable at runtime. A single instance is registered per cache manager in the GlobalComponentRegistry.

Since:
16.2

  • Constructor Details

    • MemoryMonitor

      public MemoryMonitor(double memoryThresholdPercentage, long gcDurationThresholdMs, double gcPressureThreshold, long gcPressureWindowMs)
      Creates a new monitor with the specified thresholds and immediately registers JMX listeners.
      Parameters:
      memoryThresholdPercentage - fraction (0, 1.0] of old gen usage that triggers a low memory alert
      gcDurationThresholdMs - GC pause duration in ms above which a warning is logged
      gcPressureThreshold - fraction (0, 1.0] of time spent in GC over the pressure window that triggers an alert
      gcPressureWindowMs - rolling window in ms over which GC pressure is computed

    • MemoryMonitor

      public MemoryMonitor()
      Creates a new monitor with default thresholds: 85% memory, 5000ms GC duration, 20% GC pressure over a 60s window.

  • Method Details

    • stop

      public void stop()
      Removes all registered JMX notification listeners. Called during cache manager shutdown.

    • isMemoryLow

      public boolean isMemoryLow()
      Returns:
      true if old generation heap usage has exceeded the memory threshold

    • isGcPressureExceeded

      public boolean isGcPressureExceeded()
      Returns:
      true if GC time over the pressure window has exceeded the pressure threshold

    • reset

      public void reset()
      Clears all alerts and discards recorded GC events.

    • setMemoryThreshold

      public void setMemoryThreshold(double percentage)
      Sets the old generation heap usage threshold. Clears any active low memory alert and re-applies the threshold to the memory pool.
      Parameters:
      percentage - fraction (0, 1.0]
      Throws:
      CacheConfigurationException - if the value is out of range

    • setGcDurationThreshold

      public void setGcDurationThreshold(long durationMs)
      Sets the GC pause duration threshold for log warnings.
      Parameters:
      durationMs - duration in milliseconds, must be positive
      Throws:
      CacheConfigurationException - if the value is not positive

    • setGcPressureThreshold

      public void setGcPressureThreshold(double percentage)
      Sets the GC pressure threshold. Clears any active GC pressure alert.
      Parameters:
      percentage - fraction (0, 1.0]
      Throws:
      CacheConfigurationException - if the value is out of range

    • setGcPressureWindow

      public void setGcPressureWindow(long windowMs)
      Sets the rolling window for GC pressure computation. Clears any active GC pressure alert and discards all recorded GC events.
      Parameters:
      windowMs - window duration in milliseconds, must be positive
      Throws:
      CacheConfigurationException - if the value is not positive

    • getMemoryThreshold

      public double getMemoryThreshold()

    • getGcDurationThreshold

      public long getGcDurationThreshold()

    • getGcPressureThreshold

      public double getGcPressureThreshold()

    • getGcPressureWindow

      public long getGcPressureWindow()