SiPixelPhase1TrackingParticleV does not clear trackIdToHitPtr_

[Dr15Jones]

SiPixelPhase1TrackingParticleV has the member data

std::vector<std::pair<unsigned int, const PSimHit *>> trackIdToHitPtr_

which it fills with PSimHits from the event and then does a lookup later for the hits. The problem is the code never clears the container. This means the container holds stale pointers which were from old events.

The relevant function is:

cmssw/Validation/SiPixelPhase1TrackingParticleV/src/SiPixelPhase1TrackingParticleV.cc

Line 49 in 026420d

void SiPixelPhase1TrackingParticleV::analyze(const edm::Event& iEvent, const edm::EventSetup& iSetup) {

The simplest solution would be to remove trackIdToHitPtr_ as a member data and just have it a local variable of the module.

[cmsbuild]

A new Issue was created by @Dr15Jones Chris Jones.

@davidlange6, @Dr15Jones, @smuzaffar can you please review it and eventually sign/assign? Thanks.

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[Dr15Jones]

@slava77 here is the memory problem.

[Dr15Jones]

@davidcarbonis

[Dr15Jones]

assign dqm

[cmsbuild]

New categories assigned: dqm

@kmaeshima,@vanbesien,@vazzolini,@dmitrijus you have been requested to review this Pull request/Issue and eventually sign? Thanks

[davidcarbonis]

@Dr15Jones Thanks for spotting the cause of this. Will resolve shortly.

[davidcarbonis]

PR #21084 opened with fix.

[dmitrijus]

+1

[cmsbuild]

This issue is fully signed and ready to be closed.

[Dr15Jones]

Fixed

[davidcarbonis]

@Dr15Jones I note that the current target for the closed PR is CMSSW_10_0_X and that there isn't a 9_4_0 release (only pre-release) yet. Would it be prudent/worth it to open a PR for adding this fix to 9_4_0 (assuming that the plans for using 9_4_0 haven't changed)?

[Dr15Jones]

@davidlange6 would you want a 9_4 backport of #21084 ? It would get rid of some memory hoarding and fix a reproducibility issue.