Troubleshooting FA125 Temperature Plugin Failure In Hall D Reconstruction

Hey guys,

I'm writing this because I've run into a really puzzling issue with the fa125_temp plugin in the Hall D reconstruction software. This plugin, which is designed to extract the FA125 temperature from the Df125BORConfig object within the data stream, has suddenly stopped working, and I'm scratching my head trying to figure out why. Let's dive into the details and see if anyone has some insights.

Background on the FA125 Temperature Plugin

First, a little background. The fa125_temp plugin is relatively new, designed to grab the FA125 temperature data from the Df125BORConfig object. Typically, this object is found in the very first event of the data stream. The original implementation aimed to create a histogram of these temperatures. If you are interested in the original implementation, you can check the source code on GitHub. There is also a pull request associated with it, which includes an example of the histogram output.

My initial goal was to modify this plugin. Instead of a histogram, I wanted to use a profile. This would allow us to sum data from different runs without the temperature values being incorrectly added together. However, before I even got to making those changes, I discovered that the original plugin, completely unchanged, was no longer filling the histogram. It appears the plugin is now unable to locate the Df125BORConfigs in the EVIO file. Interestingly, when using hd_dump, these configurations are found without any issues in event 0. This points to a potential problem within the plugin's data retrieval mechanism rather than the data files themselves.

The Problem: Df125BORConfig Not Found

The snippet of code used to retrieve the configurations is as follows:

auto BORvector = event->Get<Df125BORConfig>();

And the number of configurations is then counted using:

uint32_t nb = (uint32_t)BORvector.size();

The frustrating part is that when I run the plugin now, the value of nb is consistently zero, leading to an empty histogram. What's even more perplexing is that this issue persists even when using older version sets (6.1.0 and 6.2.0). The plugin definitely used to work. In fact, Alex originally identified the issue where summing histograms from multiple runs resulted in the measured temperature being multiplied by the number of runs.

This behavior is quite strange, and I’m really stumped as to what could be causing it. The fact that it's happening even in older versions suggests that something external to the plugin's code itself might be at play.

Exploring Potential Solutions and Workarounds

I do have an alternative plugin that retrieves configuration information through the CDC pulse. This plugin first retrieves Df125CDCPulse objects and then uses GetSingle to obtain the BORConfig information for the FADC that generated the pulse. While I could potentially rewrite the fa125_temp plugin to use this method, there's a significant drawback. To accurately fill the histogram, the plugin would need to wait until every FADC has written out a pulse. This could introduce significant delays and inefficiencies, especially in high-occupancy events.

Suspecting an Issue with event->Get

My current suspicion is that Df125BORConfig has somehow been removed or excluded from the list of objects accessible through event->Get. This would explain why the plugin can no longer find the configurations, even though they are present in the EVIO file and accessible via hd_dump.

This raises a critical question: What might cause Df125BORConfig to become unavailable to event->Get? Is there a configuration setting, a change in the data format, or some other factor that could be influencing this? It's crucial to identify the root cause to ensure the accurate extraction of temperature data and the proper functioning of the monitoring system.

Possible Causes and Troubleshooting Steps

To get to the bottom of this, let's brainstorm some potential causes and troubleshooting steps.

1. Data Format Changes

One possibility is that there have been changes to the data format that affect how Df125BORConfig objects are stored or accessed. This could include modifications to the EVIO format or the way the data is serialized. It's important to review any recent changes to the data acquisition system or the data format definitions.

• Action: Compare the structure of the EVIO files from a period when the plugin was working correctly with the current files. Look for any differences in the way Df125BORConfig objects are stored. Tools like EVIO browser or custom scripts can be used for this comparison.

2. Reconstruction Software Updates

Updates to the Hall D reconstruction software itself might have introduced changes that impact the plugin's ability to access Df125BORConfig objects. This could include modifications to the event processing framework, the data access API, or the way objects are registered for access.

• Action: Review the release notes and commit logs for recent software updates. Look for any changes that might affect the event->Get mechanism or the handling of configuration objects. Try reverting to an older version of the software to see if the issue is resolved.

3. Configuration Issues

Incorrect or missing configuration settings could also be a factor. The plugin might rely on specific configuration parameters to locate and access Df125BORConfig objects. If these settings are not properly configured, the plugin might fail to find the objects.

• Action: Check the plugin's configuration file and any relevant environment variables. Ensure that all necessary settings are correctly configured. Compare the configuration settings with those from a working setup.

4. Data Stream Problems

Issues with the data stream itself, such as corrupted data or missing events, could potentially prevent the plugin from accessing Df125BORConfig objects. While hd_dump can find the objects, there might be subtle issues that affect the plugin's processing.

• Action: Analyze the data stream for any signs of corruption or missing events. Check the data stream logs for any error messages or warnings. Try running the plugin on different data sets to see if the issue is specific to a particular run.

5. Object Registration Issues

It's possible that Df125BORConfig objects are not being properly registered with the event processing framework. This could prevent event->Get from finding the objects, even if they are present in the data stream.

• Action: Investigate the object registration mechanism in the reconstruction software. Ensure that Df125BORConfig objects are being correctly registered. Look for any errors or warnings related to object registration.

6. Plugin Dependencies

The plugin might have dependencies on other software components or libraries. If these dependencies are not properly installed or configured, the plugin might fail to function correctly.

• Action: Check the plugin's dependencies and ensure that all required components are installed and configured correctly. Look for any version conflicts or compatibility issues.

7. Memory Corruption

Although less likely, memory corruption could also be a cause. If memory is being corrupted, it could lead to unpredictable behavior, including the failure to find Df125BORConfig objects.

• Action: Run memory debugging tools to check for memory leaks or corruption. This can help identify if memory issues are contributing to the problem.

Next Steps and Call for Help

I'm planning to dig deeper into these potential causes. Specifically, I'm going to start by:

• Examining the data format: I’ll compare the EVIO file structure between working and non-working datasets.
• Reviewing software updates: I'll check the release notes and commit logs for any relevant changes.
• Verifying configuration settings: I'll double-check the plugin's configuration and environment variables.

I'm also open to any suggestions or insights you guys might have. Has anyone else encountered a similar issue with event->Get or the Df125BORConfig object? Any ideas on where else to look or what to try? Let's collaborate and get this sorted out!

Thanks for your help, and I'll keep you updated on my progress.

Conclusion: A Community Effort for Resolution

The mystery of the fa125_temp plugin's sudden failure highlights the complexities of large-scale scientific software. Pinpointing the root cause often requires a collaborative approach, leveraging the expertise of the entire community. By systematically exploring potential issues, from data format changes to software updates and configuration settings, we can collectively work towards a solution. The fact that the issue persists across different software versions suggests a deeper underlying problem, potentially related to object registration or data access mechanisms. Your insights and experiences are invaluable in this troubleshooting process. Please share any thoughts or suggestions you may have. Together, we can restore the functionality of this crucial plugin and ensure the accurate monitoring of FA125 temperatures in Hall D.