xrootd connections through dask not working

[sihyunjeon]

Hello,

I am using uproot through CMS purdue analysis facility (uproot is 5.5.0).

I am facing errors when trying to get access to files through xrootd but only through when it's through uproot.dask.
Below are 4 test cases i had and only the 2nd case fails, which I understood that xcache was that allows some caching of accessed data through xrootd. The ones without xcache is using global redirector to access files.

Based on the fact that everything else worked fine

1. I don't think it's my proxy problem (all other tests should've failed as well)
2. Unlike the error message I pasted below suggests, I don't think it's different environment issue (otherwise dask with global redirector should've failed).

Error during deserialization of the task graph. This frequently occurs if the Scheduler and Client have different environments. For more information, see https://docs.dask.org/en/stable/deployment-considerations.html#consistent-software-environments

import uproot
try: 
    test = uproot.dask("root://cms-xrd-global.cern.ch//store/mc/Run3Summer23NanoAODv12/QCD-4Jets_HT-400to600_TuneCP5_13p6TeV_madgraphMLM-pythia8/NANOAODSIM/130X_mcRun3_2023_realistic_v14-v3/60000/c5b8293b-65fd-4a14-a25b-2073f9bf6ac7.root:Events")
    print (test["run"].compute())
except Exception as e:
    print ("test1 failed", e)
try: 
    test = uproot.dask("root://cms-xcache.rcac.purdue.edu:1094//store/mc/Run3Summer23NanoAODv12/QCD-4Jets_HT-400to600_TuneCP5_13p6TeV_madgraphMLM-pythia8/NANOAODSIM/130X_mcRun3_2023_realistic_v14-v3/60000/c5b8293b-65fd-4a14-a25b-2073f9bf6ac7.root:Events")
    print (test["run"].compute())
except Exception as e:
    print ("test2 failed", e)
try: 
    test = uproot.open("root://cms-xrd-global.cern.ch//store/mc/Run3Summer23NanoAODv12/QCD-4Jets_HT-400to600_TuneCP5_13p6TeV_madgraphMLM-pythia8/NANOAODSIM/130X_mcRun3_2023_realistic_v14-v3/60000/c5b8293b-65fd-4a14-a25b-2073f9bf6ac7.root")["Events"]
    print (test["run"].array())
except Exception as e:
    print ("test3 failed", e)
try: 
    test = uproot.open("root://cms-xcache.rcac.purdue.edu:1094//store/mc/Run3Summer23NanoAODv12/QCD-4Jets_HT-400to600_TuneCP5_13p6TeV_madgraphMLM-pythia8/NANOAODSIM/130X_mcRun3_2023_realistic_v14-v3/60000/c5b8293b-65fd-4a14-a25b-2073f9bf6ac7.root")["Events"]
    print (test["run"].array())
except Exception as e:
    print ("test4 failed", e)

As I wrote above, only the 2nd case fails when it tries to use dask and access through xcache. The other three cases, dask with global redirector, directly opening xcache, directly opening global redirector, all works fine

It will be great if you can provide some help with this.