Bugzilla

I ran into this issue again and am revisiting it.  I am using https://sql.telemetry.mozilla.org/queries/96083/source#237307 as the source of data, and we see the Unknown_none on 10-13% of page loads.

(In reply to Martin Balfanz [:mbalfanz] from comment #5)
> Just to share some thoughts here, in case they got lost in Slack:
> * In the sql query, we're getting page loads from 100% of users and all window types/ETP settings (via use counters)

In my query, yes this is what I do.

> * However, the subquery `sample` to get the canvas data works on a 1% sample. So 22 million are probably more like 2.2 billion

I had fixed this, and I query from telemetry.main

> * Another difference is that the canvas telemetry probe is collected per tab, not per page load.

Per tab meaning... if you use a tab to visit 10 pages on 3 origins and then close the tab - that's only one entry?  That seems crazy....

> * Lastly, I'm wondering: are we collecting canvas data on every page, or does it need to have at least a canvas element present in order to count even as unknown_none? If the latter, only ~45% of pages even use a canvas element (according to chromestatus)

This may be the culprit.  We only record things if [there is a canvas extraction](https://searchfox.org/mozilla-central/source/dom/html/HTMLCanvasElement.cpp#926).

I ran into this issue again and am revisiting it.  I am using https://sql.telemetry.mozilla.org/queries/96083/source#237307 as the source of data, and we see the Unknown_none on 10-13% of page loads.

(In reply to Martin Balfanz [:mbalfanz] from comment #5)
> Just to share some thoughts here, in case they got lost in Slack:
> * In the sql query, we're getting page loads from 100% of users and all window types/ETP settings (via use counters)

In my query, yes this is what I do.

> * However, the subquery `sample` to get the canvas data works on a 1% sample. So XX million are probably more like XX billion

I had fixed this, and I query from telemetry.main

> * Another difference is that the canvas telemetry probe is collected per tab, not per page load.

Per tab meaning... if you use a tab to visit 10 pages on 3 origins and then close the tab - that's only one entry?  That seems crazy....

> * Lastly, I'm wondering: are we collecting canvas data on every page, or does it need to have at least a canvas element present in order to count even as unknown_none? If the latter, only ~45% of pages even use a canvas element (according to chromestatus)

This may be the culprit.  We only record things if [there is a canvas extraction](https://searchfox.org/mozilla-central/source/dom/html/HTMLCanvasElement.cpp#926).