Players vanishing in SMP after travelling on boats

[Mesh]

This is a problem that has been happening for a long time, but with the recent update it has become so prevalent that whenever we have to travel by boat, upon landing on shore we each have to log out and back in again because at least half of us are invisible. Boats have always had weird rubber banding issues in SMP to be fair, it just seems as though since the latest BTW update the invisibility problem is occuring with an alarmingly high frequency, unless it's just a very strange coincidence.

I've put this in Tech support because I'm not sure if it's a BTW problem or vanilla, or whether or not other people are having this problem? I suppose it could be server related because I've only really used Fragnet. So if anyone can confirm this I'd appreciate it.

Anyway it should be easy to replicate, just go out on a boat with a friend across multiple chunk distances (so the chunk in which you boarded the boat gets unloaded, before you get off the boat).

[FlowerChild]

Will take a look as what you described above rings a few bells with regards to code I revamped with the chunk stuff.

Moving over to bug reports to that end.

[FlowerChild]

My hunch did not pan out. Sorry man, I should probably not have moved this out of tech support as it may have stifled you getting additional feedback.

Will move it back there. If anyone has additional info on this, fire away.

[Ethazeriel]

Don't know that I have much more to contribute about why this is happening, but we did a bunch of boating around on a recent stream, and experienced this issue.

https://www.twitch.tv/videos/348891833

in particular, the first and last ~minute of video show this occuring.

(video starts at around 1:50 into this archive, for reference)

I did a bit more exploring later, leaving app at home - I found that even if he didn't boat at all, if I boated far away and came back he'd be invisible to me until I relogged.

[FlowerChild]

I just had a thought on this while working on something else that I wanted to record for my future reference:

Maybe this is occurring more frequently after my chunk loading rework because I'm unloading chunks more efficiently than in vanilla? Would this then imply that if the chunk where the player boarded the boat is unloaded while in transit, the player entity associated with that player on other clients is also being unloaded at that original position? Now that more chunks are being unloaded this has increased the odds of the boarding chunk being unloaded?

Will investigate further when I get a chance. Might be as simple as update the player's position throughout the boat ride, or forcing an entity unload on boarding.

[Ozziie]

Just want to add that this happened when me and my friend split up earlier in opposite directions, with no boating involved.

Fixed with a relog.

We'll be playing again tonight so will test a bit further.

[Mesh]

Well I know that entities in boats in smp have been buggy for as long as I've played minecraft. When travelling, boats are just empty, with the players rubber banding occasionally between the boat and the place they boarded it. However in the past, the players have almost always appeared fine on the other side when disembarking, until the recent update that spawned this thread. Also as Ozziie also mentions, this is now happening any time you split up from another player. This may well have happened before, but it happens almost every time now. I don't know if that helps at all

[FlowerChild]

Oh yeah, it's definitely a thing:

https://bugs.mojang.com/browse/MC-1291

I'll get to it eventually for sure. I'm on a bit of a bug fixing crusade these days :)

[Mesh]

Haha I noticed, there seems to be a hell of a lot of work going on under the hood, the animals not dying by suffocation sounds exciting. I won't mention the lighting bug though because I don't want to derail the thread or anything :O

Spoiler

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[FlowerChild]

Wow dude.

[FlowerChild]

Going to move this over to bug reports, as it appears to be part of a lager problem in multiplayer where players are disappearing even without boats being involved. This was popping up a lot in Whuppee's recent SMP streams.

Any additional info people have on the circumstances under which they've seen this occur would be appreciated, as I've yet to be able to replicate it myself.

[Hiracho]

I set up the server Whuppee used on his streams. The server is run by a .bat file with some arguments for garbage collection that were recommended to me. I am unsure this has anything to do with the issue at hand but it might be relevant.

the server bat file flags

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@ECHO OFF
java -Xms4G -Xmx6G -XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:MaxGCPauseMillis=100 -XX:+DisableExplicitGC -XX:TargetSurvivorRatio=90 -XX:G1NewSizePercent=50 -XX:G1MaxNewSizePercent=80 -XX:G1MixedGCLiveThresholdPercent=50 -XX:+AlwaysPreTouch -jar btwserver.jar
pause

I could run the server in basic settings next playthrough if you think this might affect anything

[FlowerChild]

I could run the server in basic settings next playthrough if you think this might affect anything

I suspect it wouldn't affect it, but I'm really not familiar with those settings so it's hard for me to say for certain. It might be worth a shot to play a session without them to see if it helps.

[FlowerChild]

Ok, I took some pretty drastic internal measures to try and ensure this doesn't happen, so I think it'll likely be fixed as of next release.

I'll leave the bug open though for awhile though in case anyone runs into another occurrence. Please do let me know if you do.

[FlowerChild]

Given a couple of months have gone by without additional incidents being reported, I'll assume this is dead and buried. Let me know if not.