1150529 - Remove code for expired telemetry histograms

Status: RESOLVED FIXED

(Firefox :: Session Restore, defect)

Description

[Tim Taubert [:ttaubert] (inactive)]

These telemetry histograms are going away:

FX_SESSION_RESTORE_COLLECT_SINGLE_WINDOW_DATA_MS
FX_SESSION_RESTORE_EXTRACTING_STATISTICS_DURATION_MS
FX_SESSION_RESTORE_INDIVIDUAL_CLOSED_TABS_IN_OPEN_WINDOWS_SIZE_BYTES
FX_SESSION_RESTORE_INDIVIDUAL_CLOSED_WINDOWS_SIZE_BYTES
FX_SESSION_RESTORE_INDIVIDUAL_COOKIES_SIZE_BYTES
FX_SESSION_RESTORE_INDIVIDUAL_FORMDATA_SIZE_BYTES
FX_SESSION_RESTORE_INDIVIDUAL_HISTORY_SIZE_BYTES
FX_SESSION_RESTORE_INDIVIDUAL_OPEN_WINDOWS_SIZE_BYTES
FX_SESSION_RESTORE_SEND_SERIALIZED_STATE_LONGEST_OP_MS
FX_SESSION_RESTORE_SESSION_LENGTH
FX_SESSION_RESTORE_TOTAL_CLOSED_TABS_IN_OPEN_WINDOWS_SIZE_BYTES
FX_SESSION_RESTORE_TOTAL_CLOSED_WINDOWS_SIZE_BYTES
FX_SESSION_RESTORE_TOTAL_COOKIES_SIZE_BYTES
FX_SESSION_RESTORE_TOTAL_DOM_STORAGE_SIZE_BYTES
FX_SESSION_RESTORE_TOTAL_FORMDATA_SIZE_BYTES
FX_SESSION_RESTORE_WRITE_FILE_LONGEST_OP_MS
FX_SESSION_RESTORE_WRITE_STATE_LONGEST_OP_MS

The code that submits values to those should be removed.

Comment 1

[Tim Taubert [:ttaubert] (inactive)]

Attachment: 0001-Bug-1150529-Remove-code-for-expired-telemetry-histog.patch

Comment 2

[David Teller [:Yoric] - still alive but not very active]

Comment on attachment 8600562 [details] [diff] [review]
0001-Bug-1150529-Remove-code-for-expired-telemetry-histog.patch

Review of attachment 8600562 [details] [diff] [review]:
-----------------------------------------------------------------

::: browser/components/sessionstore/SessionStore.jsm
@@ -2928,5 @@
>      if (state.session && state.session.startTime) {
>        this._sessionStartTime = state.session.startTime;
> -
> -      // ms to days
> -      let sessionLength = (Date.now() - this._sessionStartTime) / MS_PER_DAY;

Is MS_PER_DAY still used?

@@ +2911,5 @@
>     */
>    _updateSessionStartTime: function ssi_updateSessionStartTime(state) {
>      // Attempt to load the session start time from the session state
>      if (state.session && state.session.startTime) {
>        this._sessionStartTime = state.session.startTime;

This histogram strikes me as useful (although I'm not 100% sure about the implementation). Do we have any other source of data that can replace it?

Comment 3

[Tim Taubert [:ttaubert] (inactive)]

(In reply to David Rajchenbach-Teller [:Yoric] (use "needinfo" - away until May 6th) from comment #2)
> > -      // ms to days
> > -      let sessionLength = (Date.now() - this._sessionStartTime) / MS_PER_DAY;
> 
> Is MS_PER_DAY still used?

No, good catch!

> @@ +2911,5 @@
> >     */
> >    _updateSessionStartTime: function ssi_updateSessionStartTime(state) {
> >      // Attempt to load the session start time from the session state
> >      if (state.session && state.session.startTime) {
> >        this._sessionStartTime = state.session.startTime;
> 
> This histogram strikes me as useful (although I'm not 100% sure about the
> implementation). Do we have any other source of data that can replace it?

I don't know of any other source that would give us that kind of data. The current FX_SESSION_RESTORE_SESSION_LENGTH data looks rather equally distributed and doesn't tell a lot.

I'm not entirely sure if that kind of data, at least this implementation, is useful. All it tells us is that there are people that always start a new session and people that always restore their old session and thus send ping N today and N+1 tomorrow. I would argue that there are no users that would intentionally start a new session by resetting the prefs or removing the sessionstore data files. We simply have no support for starting a new session.

If we find a good definition for what a session length might be and how to implement that I wouldn't object re-adding a measurement like this. That should then just go into a separate/new bug.

I'd go and remove it. What do you think?

Comment 4

[David Teller [:Yoric] - still alive but not very active]

Sounds good to me.

Comment 5

[Pulsebot]

https://hg.mozilla.org/integration/fx-team/rev/f392bbb83496

Comment 6

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/f392bbb83496