Closed Bug 1420885 Opened 2 years ago Closed 9 months ago
Google Page-Hiding Snippet un-hide logic is delayed by tracker tailing leaving the document blank with opacity:0 for at least 4 seconds
User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36 Steps to reproduce: The problem can be reproduced with Firefox 57 Just visit our site: https://www.traum-ferienwohnungen.de/suchergebnis/ergebnisse/?is_in_clicked_search=1 Actual results: The page stays blank until the content is fully loaded. Expected results: Chunked content should be rendered partially as before (FF < 57)
User arai from the firefox irc channel could provide me with the following ticket that seemed to be helpful https://bugzilla.mozilla.org/show_bug.cgi?id=1406159 When I set network.http.tailing.enabled to false everything works fine in latest FF (just like before 57)
Thanks for the regressions range! Going to look at this.
Assignee: nobody → honzab.moz
Priority: -- → P2
Okay I'm not sure if this is relevant but the "bug" seems to be related to the page hide snippet https://developers.google.com/optimize/ from Google's Optimize tool. If I remove that one, everything works as expected, just like when I set network.http.tailing.enabled to false or use an older FF version. My brain implodes.
(In reply to Anton Frick from comment #4) > Okay I'm not sure if this is relevant but the "bug" seems to be related to > the page hide snippet https://developers.google.com/optimize/ from Google's > Optimize tool. If I remove that one, everything works as expected, just like > when I set network.http.tailing.enabled to false or use an older FF version. > My brain implodes. That's a helper, thanks and also thanks for this whole report! This is not about chunked encoding at all. The snippet hides the document content (opacity:0) and shows it in either 4 seconds or when unhidden sooner by the A/B testing script. That script loads dynamically from the ga script, we tail both because both are loading from a tracking script, and it's even worse because the tailing cascades (analytics.js has to load to start loading gtm/js?id=GTM-57Z8VSB&cid=897476427.1512149439 which unhides the document content.) It's bad that a tracking script may have such an effect, but it's understandable. It's also unfortunate that we didn't catch something like this during the Beta phase. I have to think on how we should fix this, since the first reaction to this is that we fail performance, even though the cause here is obviously not a perf issue. The intention of tailing is to help performance by delaying something that is assumed to not have any visible effect. The google's A/B experiment and the Page-Hiding Snippet apparently has...
(In reply to Honza Bambas (:mayhemer) from comment #5) > both are loading from a tracking script tracking *domain*
Summary: Chunked content only rendering when page load completed → Google Page-Hiding Snippet un-hide logic is delayed by tracker tailing leaving the document blank with opacity:0 for at least 4 seconds
Whiteboard: [necko-triaged][comment 5 explanation]
Hey Honza, can you give us a status update on this bug?
(In reply to Jim Mathies [:jimm] from comment #7) > Hey Honza, can you give us a status update on this bug? There is currently nothing we could do on our side except completely disabling the tailing (de-prioritization) feature. There is a study pending to figure out what effect tailing has on various metrics like domcontentloaded, onload, first-paint etc. If there is a regression or only very negligible improvement, we may consider it to disable. OTOH, note that the symptoms of this bug manifest also when users turn Tracking Protection to Always Enable or when they use Private Browsing windows (where TP is enabled by default). So, I think we can make this pending on the result of the study, bug 1434379.
Depends on: 1434379
Did we ever circle back to this in the 3 months since the study completed?
(In reply to Ryan VanderMeulen [:RyanVM][PTO July 4-9] from comment #9) > Did we ever circle back to this in the 3 months since the study completed? We did, but it was inconclusive (no reg, no improve). We are likely going to include tailing in the upcoming study for FastBlock (Smart Blocking) that is more detailed. Also, if FastBlock approach shows better results than tailing, tailing will be disabled for trackers (I will then file necessary bugs and duplicate this one to it.) So far I want to keep this open for reference.
It would be interesting to think about a solution here, but this is definitely no more a P2. There are no major complains regarding this issue to my knowledge. OTOH, IIRC a similar/same bug appeared more often with FastBlock being enabled. Ehsan, do you recall?
Assignee: honzab.moz → nobody
Priority: P2 → P3
Status: NEW → RESOLVED
Closed: 9 months ago
Resolution: --- → DUPLICATE
Duplicate of bug: 1516552
Resolution: DUPLICATE → WONTFIX
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