1226337 - EVENTLOOP_UI_{LAG,ACTIVITY}_EXP_MS needs to become an "exceptional case" in histogram.py

Status: RESOLVED FIXED

Description

[Chris H-C :chutten]

With bug 1198196, we needed to add some special-casing in the server pipeline so that queries against EVENTLOOP_UI_{LAG,ACTIVITY}_EXP_MS histograms don't explode.

How it's been described to me: If you ask for a histogram that isn't in the data, we shouldn't fail because not all samples will have all histograms. If you ask for a histogram that _is_ in the data but whose definition is missing, we explode because it ought to be defined someplace.

bug 1198196 ran afoul of it by taking away a definition from a version where pings still contained data.

Steps to reproduce:
0) Spin up a cluster
1)
pings = get_pings(sc, app="Firefox", channel="nightly", version="45.0a1", fraction=0.01)
subset = get_pings_properties(pings, ["clientId",
                                      "environment/system/os/name",
                                      "payload/histograms/EVENTLOOP_UI_ACTIVITY_EXP_MS",
                                      "payload/histograms/EVENTLOOP_UI_LAG_EXP_MS",
                                      "payload/histograms/GOBBLEDYGOOK",
                                      "payload/simpleMeasurements/firstPaint"])
subset.count()

It'll throw a "KeyError: 'EVENTLOOP_UI_LAG_EXP_MS'"

Comment 1

[Roberto Agostino Vitillo (:rvitillo)]

I have landed the required changes in new-dev. The current t.m.o dashboard is based on the data produced in the old-dev IAM account though. Once 1220262 is fixed, the dashboard will switch over to the new-dev account.