Strange data error!

Thomas_Webb1 · December 1, 2020, 6:44pm

Just wondering if anyone else has had this problem and/or know what could have caused it.

So was doing the McCarthy special workout today and everything was going fine until the 2nd and 3rd sets of highest interval. It seemed to be the more watts I was pushing out the more lag I was getting. (I was on the big downhill segment of innsbruck for the final set not sure if speed was an issue)

The screen would essentially just freeze up for 2 to 5 seconds then catch up and play for 2 seconds so on until the interval was complete. I was in the pain locker that much I ignored it and kept my cadence and just waited until i jumped along to the arch and could ease off.

So I put it down to wifi connection lag (tethering through 4G) but on analysing my activity on strava I realised it had completely messed up the final intervals. (Those that arent familiar with the workout all 3 sets of intervals should be similar, 3minutes each interval 9mins a set). Something has literally wiped off 40-60seconds from the intervals (lap 12 and 16) and wiped up to 100watts from the average.

On my PC and the graph version of stravas analysis essentially the last minute of the interval drops down by like 100watts but stays very consistent.

So yeah is this normal? What could have caused it? Is it a one in a million chance? Any advice to avoid this would be ideal! I seem to be having a problem almost every ride at the moment!

I was going to post a screenshot of the problem but cant post media, so thought link to my workout apparently not allowed either, so hopefully you understand my issue.

Any more questions or imagery let me know!

Dean · December 1, 2020, 7:57pm

Network issues will normally manifest themselves with symptoms like other riders, rider list etc disappearing. Zwift freezing for a few moments smacks of being a local issue of some description as Zwift doesnt need a network after the ride has started to display the environment you are riding in.

Can you put you log file through Zwiftalizer.com and see if it picks up any strangeness? I havent heard of time being wiped from intervals, and 100 watt drops like you describe!!

Thomas_Webb1 · December 1, 2020, 9:07pm

Yeah I’ve checked it out. (I’m not great with tech so it’s a bit foreign to me).

My frame rate is awful. Throughout the ride avg 23. The last 20minutes of the ride it was really sporadic.
My ant device had one re pair so nothing to worry about there
Network errors the last 5 minutes of the ride varies but the bars are there between 5 to 60 (whatever that means)
TCP connection attempts again last 5 minutes anything from 0 to 5
The game version is out of date now. But I am pretty sure at 10am UK during the ride it was in date.

It is so odd. Looking at the “Laps” now on strava PC it essentially looks like that I stopped and started the intervals too early. But there is a minute missing somewhere.

This may remain unsolved! Hopefully a one off. I’ve been online and played with settings to optimise my frame rate for future rides

I could have been blowing that much I thought I went through an arch, and eased off to early … but I wouldn’t have then started early after a 9min recovery

At some point when able I will post links and images

Dean · December 1, 2020, 9:14pm

People have been reporting adhoc ERG issues in recent times but I’m fairly sure taking on that workout, you’d be keeping a close eye on starts/ends.

No harm uninstalling your Zwift and reinstalling - that may just clear some gremlins.

If you want to send your log through to me, I’ll post up the pic, zwiftposts@gmail.com. Think the post count is 5~10 before you can put things up. Otherwise put pics on file share service and swaps “.” for say “_” in the url.

Thomas_Webb1 · December 3, 2020, 3:55pm

Haven’t yet got round to an uninstall just yet (work). However did another workout late last night and had to start again and use my phone as my laptop was lagging so much in the warmup.

Same lap data error on strava, however I have uploaded the fit file to training peaks and the laps reads correctly so essentially I think that the lap data is being messed up in the transfer from zwift to strava.
(EDIT: ON CLOSER INSPECTION THIS STATEMENT IS INCORRECT IT IS IN FACT DOING THE SAME ON TRAINING PEAKS)

This happens in and out of ERG mode. I usually prefer to ride manually but was forced to ride in ERG due to using my phone (wattbike atom no visual gear changes).

This doesnt solve my awful lag and FPS issues (the last ride was unworkable) but they dont seem to be related. I may start a new topic about my lag issues if i cant sort it myself this side of xmas!

Hopefully this thread will help if anyone else has the same strava problem or any suggestions.

Thomas_Webb1 · December 3, 2020, 10:50am

Not sure if this will work but here is a link to the initial workout that was wrong. The one yesterday is also public on my profile.

If you analyze the laps on the graph with a PC you can see where the laps have started and finished in the wrong places.

Check out my activity on Strava:
https://
strava_app_link/UIbm7mWGUbb

_ = .

Thomas_Webb1 · December 4, 2020, 2:03pm

FINALLY able to post images pictures paint a thousand words as you can see the laps shift right at some point, messing up all analysis

Dean · December 5, 2020, 2:26am

I dont know Training Peaks but presume the semi-transparent pink boxes are the “laps” or intervals. Yeah that is a strange timewarp thing happening there!

You seem to be getting a lot of network errors, at least in comparison to mine (none). I do wonder whether the workout mode is more reliant on the network and therefore causing yoru problems (lag). Do you mind sending me your log? Send to me on zwiftposts @ gmail.com - I’m keen to see the log msg’s to see if they throw any more light on this.

Questions - if you run an internet speed test, do you have good down/upload speeds and low latency (ping)? And if you were just riding in say Watopia, do riders flicker in and out now and then? From your description, its a once-off so far, so has anything changed in your environment recently (PC, network).

Thomas_Webb1 · December 5, 2020, 4:28pm

Yeah that is correct the pink boxes represent laps.

I have emailed over the 2 logs from those specific rides. I have since reverted to using my mobile phone instead on a 4G network and I have had zero problems apart from eye strain from a small screen, but I can live with it!

So my internet speeds are not the greatest when using wifi due to the bike being in an outhouse at the rear of my garden so runs through a booster. We are talking download 15MB/sec, upload 20MB/sec and ping 15 seconds. However recently it has dropped down to about 5 download, 15 upload and same ping (not sure if the winter weather is having a play as that is the only thing that has changed).

Because of this i decided to load my workout and the map in the house on main WiFi then move to the outhouse and use my phone as a dongle, strong 4g signal. Was getting about 30MB/sec download and upload 40 but the ping was about 35, I managed a fair few rides with this set up before the above problems started happening. However now because of the issues, i have just cut out all bridges and use the phone (so far so good).

Yes the riders do flicker when the screen is actually moving. It really got to a point where i was freezing and jumping along the road about 100m a time.

Many thanks for all your help so far!

Dean · December 6, 2020, 5:31am

Righto - just to clarify, your ping is 15 milliseconds and not seconds mentioned above, right? 15ms isnt exactly fast, but its not terrible. But you mention above your ping can get up to 35/40ms. I would suggest that is starting to push the limits.

I’ll post a pic of one of your Zwiftalizer view of logs here for others but some observations (and bear in mind I am not a pc person):

Your screen FPS drops to a really low number but is often OK. Something is being stressed periodically and may be consistent with the FPS issues some of us have been having for the past weeks since a Nov update.

You are getting quite a high 2-4% ANT failure rate is unlikely to be helping.

Networks - your network is not great and the error condition being picked up and mentioned in the logs is interesting Couldn’t resolve host name’ for: GET https://us-or-rly101.zwift.com/api/profiles? [snipped]

So this tells me Zwift is trying to get some data, likely your workout data, from a host but because it cant resolve the name, it cant get the data. This is in your Log (old 1). You could also be using a really slow DNS server and its not responding quickly enough for Zwift’s liking. It would be nice if Zwift had a FAQ covering log msg interpretation!

I’m guessing, with the recent updates where played around with video performance (to our detriment and causing a lot of lower FPS issues for some folks) will not have helped you at all. But with your network not being very clean, I think those events are causing the issue of causing Zwift to get confused with timestamps.

I’d suggest you log a support ticket with zwift with a focus on asking what the likely outcome of that error in your logs is. Many would suggest you get your network sorted too. Powerline if you cant run an ethernet cable seems popular for people. Also, you can x your fingers and hope Zwift fix up there current video problem. Also, some people here might be able to help you tune your vid card/pc a bit. Finally, if you did a workout in your house with current setup, would you get the issue? If not (which I suspect you wont), then that will really determine what you should do next (hardwire your network to your cave.).
FPS:

ANT:

Network: