Speed up reading *Auxiliary fields in RNTupleTempSource

[makortel]

PR description:

In the context of #48400 (but not as full resolution) this PR speeds up the initial reading of the *Auxiliary fields. With the input file in #48400 that had 2.5M tiny events, the initial read of EventAuxiliary went from 6.6 hours to ~1 second.

Resolves cms-sw/framework-team#1785

PR validation:

Workflow 139.005 step3 starts much faster.

[cmsbuild]

cms-bot internal usage

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-49902/47636

[cmsbuild]

A new Pull Request was created by @makortel for master.

It involves the following packages:

• FWIO/RNTupleTempInput (core)

@Dr15Jones, @cmsbuild, @makortel, @smuzaffar can you please review it and eventually sign? Thanks.
@ftenchini, @mandrenguyen, @sextonkennedy you are the release manager for this.

cms-bot commands are listed here

[makortel]

test parameters:

• enable_tests = rntuple

[makortel]

@cmsbuild, please test

[cmsbuild]

+1

Size: This PR adds an extra 40KB to repository
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-8a4860/50822/summary.html
COMMIT: 23de48d
CMSSW: CMSSW_16_1_X_2026-01-22-1100/el8_amd64_gcc13
Additional Tests: RNTUPLE
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/49902/50822/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially removed 4 lines from the logs
• Reco comparison results: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 52
• DQMHistoTests: Total histograms compared: 4025536
• DQMHistoTests: Total failures: 3
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 4025513
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 51 files compared)
• Checked 222 log files, 193 edm output root files, 52 DQM output files
• TriggerResults: no differences found

[makortel]

+core

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @sextonkennedy, @mandrenguyen, @ftenchini (and backports should be raised in the release meeting by the corresponding L2)

[makortel]

@gartung @smuzaffar The max memory report does not seem to be reported for RNTuple presently. Is that expected?

[mandrenguyen]

+1

[smuzaffar]

@gartung @smuzaffar The max memory report does not seem to be reported for RNTuple presently. Is that expected?

@makortel , as cms-sw/cms-bot#2651 is not yet merged (which enables rntuple tests comparison) so that is why you dop not see max memory comparsion results for rntuple . We need to fix the issue of hanging edm tools before enabling the runtuple PR comparsion

[makortel]

Ok, thanks for the clarification!