GlueX Software Meeting, August 4, 2020

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GlueX Software Meeting
Tuesday, August 4, 2020
3:00 pm EDT
BlueJeans: 968 592 007


  1. Announcements
    1. Draft of DSelector documentation (Sean)
  2. Review of Minutes from the Last Software Meeting (all)
  3. Restoration of Execution Tests for Pull Request Builds (Sean)
  4. Sluggish Response on (all)
  5. Python 3 Compatible Build System (Mark)
  6. dE/dx theta Correction (Naomi)
  7. Review of recent issues and pull requests:
    1. halld_recon
    2. halld_sim
    3. CCDB
    4. RCDB
  8. Review of recent discussion on the GlueX Software Help List (all)
  9. Action Item Review (all)


Present: Alex Austregesilo, Thomas Britton, Mark Ito (chair), Richard Jones, Naomi Jarvis, David Lawrence, Susan Schadmand, Beni Zihlmann

There is a recording of his meeting on the BlueJeans site. Use your JLab credentials to authenticate.


Draft of DSelector documentation. See Beni for the link to edit the Overleaf document.

Review of Minutes from the Last Software Meeting

We went over the minutes from July 21.

Corrupt CCDB SQLite Files

Mark reported that instances of corrupt CCDB SQLite files have occurred several times over the past two weeks. Recall that the error is "Lost connection to MySQL server." The new size requirement has been catching them and bad ones are not getting shipped to Oasis.

Compiler upgrade discussion

Mark reported that Richard's HOWTO on installing and running cvmfsexec allowed him to easily install Oasis on Mark's RHEL7 box at the Lab. This, coupled with our standard container, allows almost instant access to a JLab-like development/running environment, as advertised. With a CentOS 8 container, which is in the works, it could ease our transition to a more advanced version of GCC.

Restoration of Execution Tests for Pull Request Builds

This] is working now. Sean Dobbs may have more to say at the next meeting. Mark pointed out that there is new environment set-up scheme to ensure consistency between building and running the binary tests.

Sluggish Response on

Several people have been noticing periods of slow response from our main webserver,, including, not not limited to, use of the wikis. Yesterday morning the server was timing out on requests, not good at all. Mark reported that during slow-downs, the webserver has plenty of idle CPU cycles and does not appear to be swapping. It is the case that the majority of web requests during these times are from the MCwrapper Dashboard, at the level of a few Hertz from multiple browser clients. Thomas assured us that those operations are light weight and cannot account for the slow-downs. Going forward:

  • Thomas has increased the period between updates requests from the browser application, despite his assertion that those requests cannot possibly be the problem, at Mark's request.
  • Naomi suggested that people submit ServiceNow requests (write an email to whenever a problem is encountered. That might raise the visibility of the issue.
  • Mark mentioned the possibility of putting up a dedicated server, either a webserver, database server, or both, to move the load away from other essential functions on halldweb.
  • Mark also suggested that the Computer Center implement some sort of history mechanism that might help identify the bottleneck.

dE/dx theta Correction

Naomi reported that her improvements to the CDC dE/dx measurement located on this branch are ready to go. She expressed her concern that the dE/dx quantities would undergo a sudden change if this branch were merged, making those quantities inconsistent with those encoded in REST files from previous reconstruction launches. Mark said that similar improvements are merged all the time. Beni gave a strong suggestion that the pull request be composed. [Added in press: Naomi submitted the pull request and Beni merged it with the comment "too good to not have."]

Python 3 Compatible Build System

Mark described the changes, announced last week, that allows us to build our software on either a Python-2-based system or on one based on Python 3. See his slides for details. This work is a first step at developing a container system for CentOS 8.

Review of recent issues and pull requests

David called our attention to halld_recon Issue #418, hd_root hangs at the end of evio file with is_valid_run_end = false, originally submitted by Naomi. Richard will have a look.

Review of recent discussion on the GlueX Software Help List

We went over two items: