HPCC-33244 Extend BlockedTimeTracker to allow concurrent query load to be estimated

[ghalliday]

Type of change:

• This change is a bug fix (non-breaking change which fixes an issue).
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• This change alters the query API (existing queries will have to be recompiled)

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[github-actions]

Jira Issue: https://hpccsystems.atlassian.net//browse/HPCC-33244

Jirabot Action Result:
Assigning user: gavin.halliday@lexisnexisrisk.com
Workflow Transition To: Merge Pending
Updated PR

[ghalliday]

@mckellyln the unit tests demonstrate how to use the code.
I am in two minds about the interface. It would be simpler if the 3rd parameter was removed from the extractOverlapInfo() function, but that means the critical section would need to be obtained twice. There is unlikely to be much contention, but it is a minor overhead. I have tried to minimize the cs window reduce contention.

The two unit tests illustrate the difference with or without the 3rd parameter.

[mckellyln]

I think this looks good.

[mckellyln]

Can DummyInfo be used in parallel ?

[ghalliday]

Can DummyInfo be used in parallel ?

It could - in practice it would be another thread calling those functions with real values.
Any opinion on whether it is better with or without that 3rd parameter?

[mckellyln]

I am ok with the increment arg, but I do like the interface a little better without it.
So I guess lets go with removing it.

[ghalliday]

@mckellyln cleaned up interface pushed and test case simplified to match it. Will merge once tests pass.