IBM WebSphere Application Server Performance Cookbook

IBM App Connect Enterprise

IBM App Connect Enterprise (ACE) is formerly known as IBM Integration Bus (IIB), and before that, WebSphere Message Broker (WMB). It is a combination of a C/C++ program and a JVM.

Terms

  • Integration Server (also known as a DataFlowEngine [DFE] or an Execution Group): Where message flows and resources are deployed and executed. This process includes the JVM.
  • Integration Node: An optional process that manages a set of integration servers (not applicable to containers).
  • "Additional instances" are basically the available number of worker threads.

Set JVM options

Java arguments may be specified with environment variables (e.g. IBM_JAVA_OPTIONS) or with mqsichangeproperties [...] jvmSystemProperty. The downside of using environment variables is that multiple execution groups may use a single profile script, thus, per-execution group settings cannot be specified.

jvmSystemProperty

To set JVM options using the mqsichangeproperties jvmSystemProperty sub-command, first list the existing system properties:

mqsireportproperties $NODE -e $SERVER -o ComIbmJVMManager -n jvmSystemProperty

Then, prepend the results of the above command (if any) with the updated arguments into the last argument of the following command. Wrap the entire JVM options string with single quotes and each argument inside with double quotes; for example:

mqsichangeproperties $NODE -e $SERVER -o ComIbmJVMManager -n jvmSystemProperty -v '"-Xverbosegclog:verbosegc.%seq.log,20,50000" "-Doption1=true"'

Using environment variables

Java arguments may be specified with the environment variable IBM_JAVA_OPTIONS for IBM Java. Environment variables are generally set in the profile. First, check if IBM_JAVA_OPTIONS is already in the profile. If it is, append the arguments; otherwise, add the export; for example:

export IBM_JAVA_OPTIONS="-Xverbosegclog:verbosegc.%seq.log,20,50000 -Doption1=true"

Verbose garbage collection

Verbose garbage collection is generally recommended for production with benchmarks showing an overhead of ~0.1%. Verbosegc helps investigate OutOfMemoryErrors and garbage collection overhead.

ACE/IIB JVMs may share the same current working directory (e.g. $WORKPATH/common/errors); therefore, to allow sets of rotating verbosegc files for each JVM, add a unique name to each JVM's added options; for example, replace both instances of $SERVER with each JVM's unique name in the following example (combining with pre-existing mqsireportproperties, if any):

mqsichangeproperties $NODE -e $SERVER -o ComIbmJVMManager -n jvmSystemProperty -v '"-Xverbosegclog:verbosegc.$SERVER.%seq.log,20,50000"'

Request Thread Dump

By default, ACE/IIB set -Xdump:heap:events=user -Xdump:snap:events=user so kill -3 $PID will produce a heapdump (*.phd) and snapdumps (Snap*.trc) in addition to a thread dump (javacore*txt). There is no way to disable this.

To produce a thread dump without a heapdump and snapdump, on ACE >= 11.0.0.9 and IIB >= 10.0.0.9, you may use mqsichangeproperties [...] core:

mqsichangeproperties $NODE -e $SERVER -o ComIbmInternalSupportManager/Java/JVM -n dump -v core

Thread dumps are generally written to $WORKPATH/common/errors/

Request Heap Dump

To produce a heap dump, on ACE >= 11.0.0.9 and IIB >= 10.0.0.9, you may use mqsichangeproperties [...] heap:

mqsichangeproperties $NODE -e $SERVER -o ComIbmInternalSupportManager/Java/JVM -n dump -v heap

Heap dumps are generally written to $WORKPATH/common/errors/

Request System Dump

To produce a system dump, on ACE >= 11.0.0.9 and IIB >= 10.0.0.9, you may use mqsichangeproperties [...] system:

mqsichangeproperties $NODE -e $SERVER -o ComIbmInternalSupportManager/Java/JVM -n dump -v system

However, currently, this mechanism does not use request=exclusive+prepwalk so it is not recommended. Instead, see J9 System Dump Recipe.

JDBC

The JDBC connection pool idle timeout is set with the environment variable MQSI_JDBC_POOL_EXPIRY (in seconds) which defaults to 900 seconds (15 minutes). The maximum value is 100000000 (~3 years).

The JDBC query timeout is set with the environment variable MQSI_POOL_DBCALL_TIMEOUT (in seconds) which defaults to 15 or 60 seconds depending on APAR IT34228. The maximum value is 600 or 18000 seconds depending on APAR IT34228.

The JDBC monitoring statistics include connection pool utilization but do not include average drive response time.

Diagnostic Trace