From IRC: > categorical histograms could be stored in structs which is what we are already doing in main_summary: > https://github.com/mozilla/telemetry-batch-view/blob/master/src/main/scala/com/mozilla/telemetry/views/MainSummaryView.scala#L387 > Probably using maps is the better choice as it allows to use cross join unnest

I need some clarification on this. The histograms.json [0] file only lists two example categorical histograms. Are there histograms missing from this set or are we expecting more in the future? Is there an easy way to enumerate these besides filtering past pings? [0] https://hg.mozilla.org/releases/mozilla-release/raw-file/tip/toolkit/components/telemetry/Histograms.json

(In reply to Ryan Harter [:harter] from comment #1) > I need some clarification on this. The histograms.json [0] file only lists > two example categorical histograms. Are there histograms missing from this > set or are we expecting more in the future? Is there an easy way to > enumerate these besides filtering past pings? We are expecting more in the future. AFAIU the plan is that once the tooling is in place, data collection reviewers can point engineers to using them.

(In reply to Ryan Harter [:harter] from comment #1) > Is there an easy way to enumerate these besides filtering past pings? Not right now, although i'm thinking about how to fix this.

I tried to find some example pings from the test histograms, but they don't seem to be reporting [0]. Do we have examples or a spec for these histograms payloads? The docs mention these will be like enumerated histograms with labels, but the format's still unclear to me. Will they payload be an array, as in a enumerated histogram, or a map? Thanks! [0] https://gist.github.com/harterrt/ed44bdd4e07b75be652154f5d706eef6

(In reply to Ryan Harter [:harter] from comment #4) > Will they payload be an array, as in a enumerated > histogram, or a map? Thanks! Yes, in the payload they are just like enumerated histograms. The labels are only used in the client API, internally it is just like an enumerated histogram. E.g. for TELEMETRY_TEST_CATEGORICAL, adding 1 to the labels "CommonLabel" & "Label2", <ping>/payload/histograms/TELEMETRY_TEST_CATEGORICAL looks like this: > {"range":[1,3],"bucket_count":4,"histogram_type":1,"values":{"0":1,"1":1,"2":0},"sum":1}

Note that we are changing the bucket logic in bug 1312806 to reduce user error. Bug 1324478 was filed to deal with this from telemetry-batch-view.

Moving to P3. I do not plan on addressing this in Q2.

Moving to P2, due to Bug 1376596

I will not be able to take care of this in the next month. Moving to P3.