Heap Substitute: An Alternative to Heap Dump Analysis

When analyzing large heap dump files, it’s often necessary to allocate a significant amount of memory for the analysis tool to parse the file and load the heap report in the browser. As a general recommendation, we suggest configuring the -Xmx value to 1.25x to 2x the size of the uncompressed heap dump file to ensure smooth processing. However, as heap dump files can vary greatly in size and complexity, this heap memory (-Xmx) allocation might not always be feasible, especially for very large heap dumps.

Heap Substitute as an Alternative

To help you manage memory limitations, we offer an alternative to large heap dumps through our Heap Substitute option. This lightweight substitute provides a high-level overview of the heap such as a summary of all objects in the heap, along with their count and the size they occupy without the complexity of a full heap dump. It’s especially useful in situations where a heap dump is too large to handle or where memory constraints make it difficult to allocate sufficient heap memory (-Xmx).

Unlike a full heap dump, Heap Substitute does not allow you to drill down into each object or examine the raw data and references between objects. However, it provides valuable insights into memory consumption and object distribution in a much more memory-efficient way.

Benefits of Heap Substitute

• Memory Efficiency: Heap Substitute requires significantly less memory than a full heap dump, making it suitable for large heap dumps that are otherwise too difficult to analyze due to memory constraints.

+ Quick Overview: Provides a high-level summary of memory usage and object allocation, which can help you quickly identify potential areas of concern without requiring extensive memory resources.

Limitations

Less Detail: Unlike a full heap dump, Heap Substitute does not provide in-depth analysis, such as the ability to drill down into specific objects, their references, or raw data. It’s a summary tool that gives you an overview of memory usage and object counts but lacks the detailed analysis available with a full heap dump.

Capturing Heap Substitute

You can use our open-source script to capture Heap Substitute, along with other essential troubleshooting artifacts from your application, as shown in the screenshot below.