723590 - [Telemetry dashboard] Histogram with 1 data point is displayed badly.

Status: RESOLVED WONTFIX

(Mozilla Metrics :: Frontend Reports, defect)

Description

[Justin Lebar (not reading bugmail)]

See IMAGE_DECODE_RATE_JPEG.  I added this histogram in a patch, but it hasn't been pushed yet, so there is just one sample: "1 points (all applicable samples)."

And yet there's more than one non-zero bar in the histogram.  Is some kind of smoothing being applied?  Whatever it is, it's generating a flat-out incorrect histogram.

Moreover, why doesn't the "Submissions By Date" graph at the bottom reflect the filtering I've applied?  It seems to be showing all submissions, rather than all submissions which include the relevant histogram.

Comment 1

[Paulo Pires]

1 point means that only one person has "worked" on that measure.

The bars correspond to the count of each value, such as:
"3501":0
"4387":1
"6888":1
"10813":2
"16975":5
"21269":16
"26650":58
"33392":65
"41839":53
"52423":6
"65685":0

The filters below the title "Histogram" are only applied to the Histogram.
The filters on the left, and the date on top, affect all the dashboard.

Comment 2

[Justin Lebar (not reading bugmail)]

> 1 point means that only one person has "worked" on that measure.

I don't understand what you mean.

Does "1 point" mean we only received one relevant telemetry ping?  If so, perhaps it should say "1 ping"; that would line up with the nomenclature we use.

> The filters below the title "Histogram" are only applied to the Histogram.
> The filters on the left, and the date on top, affect all the dashboard.

Understood.  I'm saying this is not how things should be.  Or at least, that there should be a way to see how the number of pings you've gotten *for this histogram* has changed over time.  That is usually what I'm interested in.

There should also be a way to see this current global histogram.

Comment 3

[Pedro Alves]

> Understood.  I'm saying this is not how things should be.  Or at least, that
> there should be a way to see how the number of pings you've gotten *for this
> histogram* has changed over time.  That is usually what I'm interested in.


This is exactly the kind of information that telemetry evolution provides. Isn't that what you're looking for?

Comment 4

[Justin Lebar (not reading bugmail)]

Well, that page certainly looks cool, if it ever finishes loading!

I'm specifically interested in having a subset of that information available while I'm looking at the histogram.  Put another way, the per-histogram submission frequency is much more important to understanding the main histogram than the global submission frequency.

Again, a use-case is understanding that a histogram suddenly stopped being reported in recent pings, either because the histogram was removed from the code, there was a bug, or something.  Or understanding that a histogram just started getting pings a day ago.  At the moment, this is not clear unless you go to the Telemetry Evolution page and wait for it to load.

Comment 5

[Annie Elliott]

Marking: in group of > 33 asks for Telemetry that need PM priority before triage/scheduling.

Comment 6

[Annie Elliott]

Triaged.

Comment 7

[(dormant account)]

Justin, IMAGE_DECODE_RATE_JPEG is no longer shown. I don't see it in the histograms file, do you have another example of this problem?

Comment 8

[Justin Lebar (not reading bugmail)]

IMAGE_DECODE_RATE_JPEG was a temporary name for a histogram I was playing with, I think.

If I understand this (old) bug correctly, the problem was that the "ping count" at the bottom did not reflect filtering above.  So it was showing tons of pings received, when I thought it should have been showing very few pings received, because very few pings that we received had this histogram present.  

That's what I think I'm talking about in comment 2, iiuc.

I never use the old histogram view anymore, so I can't say this matters to me.

Comment 9

[Lawrence Mandel [:lmandel] (use needinfo)]

Given that Justin no longer has an issue I'm going to resolve this bug. We can reopen if someone else has the same issue.