Taking snapshots of your running ColdFusion application’s memory state and active threads, known as heap and thread dumps, can provide invaluable diagnostic insights. This information helps in debugging, identifying performance issues, and troubleshooting potential problems within your application. The goal of this article is to explain how to use the jcmd tool to generate these dumps.
Prerequisites
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Java JDK has to be installed for this to work.
If you do not have the Java JDK installed on your VPS, then you will need to follow the documentation below:
How to Download and install Java JDK - Drafts - xByte Hosting Wiki
1. Heap Dump
A heap dump is a snapshot of all objects present in the memory at any given moment, serving as a critical tool for understanding memory usage patterns and spotting potential memory leaks.
To generate a heap dump in ColdFusion using jcmd:
For Windows
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Ensure you have the JDK installed, which provides the
jcmdtool. -
Open Command Prompt with Administrator privileges.
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Identify the process id (PID) of your ColdFusion service. You can achieve this by following the instructions here on finding process PID:
Finding a Process PID on Windows - Windows - xByte Hosting Wiki
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Run the command:
jcmd <PID> GC.heap_dump <filepath>Replace<filepath>with the path and filename where you want the dump to be stored, and<PID>with the process id of your ColdFusion service.
2. Thread Dump
A thread dump is a snapshot of all threads currently active in your Java Virtual Machine (JVM). It is an excellent tool for identifying issues related to concurrent execution and potential bottlenecks.
To generate a thread dump in ColdFusion using jcmd:
For Windows
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Make sure the JDK is installed.
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Open Command Prompt with Administrator privileges.
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Identify the process id (PID) of your ColdFusion service. You can achieve this by following the instructions here on finding process PID:
Finding a Process PID on Windows - Windows - xByte Hosting Wiki.
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Run the command:
jcmd <PID> Thread.print > <filepath>Replace<PID>with the process id of your ColdFusion service, and<filepath>with the path and filename where you want the dump to be stored.
In all the above cases, make sure that you replace <filepath> with the complete path and filename of the dump file you want to create. Replace <PID> with the process id of the running ColdFusion service.
By leveraging the jcmd tool, you can efficiently generate heap and thread dumps of your ColdFusion application service. The resulting dumps can then be used to analyze the state of your application, offering crucial insights into potential performance issues or bottlenecks.
You can submit a thread dump and heap dump to our team at [email protected] and we’ll perform root cause analysis on it