JVM
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JVM

Heap size

By default, TIBCO StreamBase® Runtime doesn't modify the JVM heap (-Xms<size> and -Xmx<size>) or stack (-Xss<size>) memory options. If during testing, the JVM is found to run short of, or out of memory, these options can be modified either setting them as arguments to the deployment tool.

Both JConsole and VisualVM can be used for looking at heap memory utilization.

Garbage collection

By default, TIBCO StreamBase® Runtime doesn't modify any of the JVM garbage collection parameters.

For production systems deploying using the Oracle JVM, we recommend that you enable garbage collection logging using the following deployment options:

  • -XX:+PrintGCDateStamps

  • -XX:+PrintGCDetails

  • -Xloggc:gc.log

    Note: replace gc.log with a name unique to your deployed JVM to avoid multiple JVMs from colliding using the same log file.

This will be provide a relatively low overhead logging that can be used to look for memory issues and using the timestamps may be correlated to other application logging (e.g. request/response latency).

Another useful set of Oracle JVM option controls GC log file rotation. See (Java HotSpot VM Options).

  • -XX:-UseGCLogFileRotation

  • -XX:-NumberOfGCLogFiles

  • -XX:GCLogFileSize

Garbage collection tuning is a complex subject with dependencies upon the application, the target load, and the desired balance of application throughput, latency, and footprint. Because there is no best one-size-fits-all answer, most JVMs offer a variety of options for modifying the behavior of the garbage collector. An Internet search will show a large selection of writings on the subject. One book with good coverage on the implementation and tuning of garbage collection in Oracle JVMs is Java Performance by Charlie Hunt and Binu John.

Out of Memory Heap Dump

When deploying using the Oracle JVM we recommend setting the following JVM deploy option which will cause a JVM heap dump to be logged upon an out of memory error within the JVM:

-XX:+HeapDumpOnOutOfMemoryError

Multiple JVMs

Typically, an TIBCO StreamBase® Runtime deployment will consist of a single JVM per node. However, there may be cases where multiple JVMs per node are required (e.g. Exceeding a per-process limit on the number of file descriptors).

TIBCO StreamBase® Runtime supports multiple JVMs deployed within a single node. These JVMs may all access the same Managed objects.

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