Sync Bug

Overview

This page is intended to explain the so-called "sync bug" that many players are experiencing for the first time following the issue 12 release. (note: this bug is actually much older, and tends to occur whenever the server populations are high)

It's also intended as something that Professor Immortal can point to so he doesn't have to keep explaining things on /help. (As such, it contains mostly information Professor Immortal has obtained himself, which may be of dubious accuracy on some points, plus possibly submissions from other wiki editors.)

Description

The Sync Bug usually occurs when the player is experiencing high latency. (Latency can be monitored using the /netgraph command.)

At some critical point during client/server communications, an error occurs that causes the player's client to cease being synchronized with the server. This results in the player being unable to move or target powers, because his client isn't relaying commands to the server correctly. Additionally, he can't see or interact with any other game character who is out of range of his real position (including objects like doors and the edges of the zone). Note that teammates can be still be seen regardless.

The really strange thing that occurs during a sync bug is that the player still appears to retain control of his character and can move around in an "abandoned" zone, from his point of view. Other players see him standing still, but the player sees himself apparently able to move around normally. However, he can't see or interact with anything that isn't near his real position.

This is apparently caused by the communication error between the client and server, with the client attempting to extrapolate what the player should be seeing in response to his movements, but without updating the server on the player's actions or receiving updates from the server on the position of everything else relative to the player. (Something similar probably happens during rubberbanding.)

Luckily, chat channels still function normally.

Solutions

Any power or command which forces the player's position to change outside of normal movement (normal movement including running, jumping, flying) should correct the bug, although it will not eliminate the cause of the bug.

Teleportation powers should correct a player's position instantly, and force the client and server to correct their synchronization. Due to targetting issues the player is having, Teleport and Team Teleport may not work, but Recall Friend and Teleport Foe should correct the issue. Assemble the Team and Summon Teammates should also work. Other powers imitating these teleportation abilities (such as those belonging to Warshades) are equivalent).

Self-transportation powers (that don't require a target) should also instantly correct a player's position, however a player who is susceptible to the sync bug may experience it again in the new zone. The Pocket D VIP Pass, the Consignment House Transporter, the Black Market Transporter, and the Base Transporter should do the trick.

Additionally, a player can use an Ouroboros Portal to leave, although he may have trouble using his own. A teammate's should work fine, if the player who is desynced is near his actual location.

Finally, if all of the above options fail, a player can log out of the game and back in (restarting the game should not be necessary).

An upcoming slash command, /sync will resynchronize the client and server and is being tested on the training server. [1]

Further Reading

Lighthouse has asked players suffering from this bug to report, as can be read here [2].