Bentobox: Island deletion is taking too long

[Sckaletz]

Description
Our server keeps crashing after a few minutes with this error. Using the latest Spigot 1.13.2 build:

https://pastebin.com/L76VvkPX

Server Information:

• Database being used: YAML
• OS: Ubuntu 18.04
• Java Version: Java 8
• BentoBox version: 1.0

• Addons installed?
  BSkyBlock 1.0, BentoBox-Challenges 0.0.3-SNAPSHOT, Level 0.2.0

• Other plugins?
  PlaceholderAPI, NametagEdit, AutomaticInventory, Arconix, AuctionHouse, DeluxeTags, ChatFeelings, ChestMaster, LuckPerms, WorldEdit, Skript, OpenInv, ClearLag, ChatControl, SkQuery, Votifier, ProtocolLib, NightVision, LibsDisguises, GuiRedeemMCMMO, VotingPlugin, MVdWPlaceholderAPI, AsyncWorldEdit, IPWhitelist, VoidGenerator, Sellwands, FeatherBoard, GhostBlockKiller, mcMMO, Vault, EpicHeads, HolographicDisplays, WolvSK, WorldGuard, Essentials, GadgetsMenu, MarriageMaster, Jobs, EpicSpawners, BuycraftX, DeluxeChat, Citizens, BentoBox, SuperVanish, WildStacker, EssentialsSpawn, TitleManager, ShopGUIPlus, CrateReloaded, AdvancedOreGen

[Poslovitch]

@tastybento The error comes from BSkyBlock's generator. Any ideas?

[BONNe]

It could be the same as in #431

[BONNe]

I do not know if...
but isn't it an issue with ore generators? Here AdvancedOreGen but in 431 is used CustomOreGen.

[mercurialmusic]

This looks similar to an error and server timeout (not crash) we've been experiencing every time someone resets their island. Throws errors about chunk generation, and while we don't use any OreGen plugins, we are also running it on the same server that has PlotSquared (another custom generator), although the two shouldn't be interacting. The error thrown seems to finger PlotSquared as the culprit, which is why I haven't submitted a report here, but I notice these also use another custom generator (VoidGenerator) and I wonder if BentoBox might be not playing nice with other world generators? It doesn't make sense, and I know this isn't very helpful since I don't have my error reports on hand, but who knows. I'll see if I can dig it up and will post it.

[tastybento]

No. This is not an issue with other plugins or anything. It's that the island deletion is taking too long in the main thread and so the Spigot watchdog timer is kicking in. This occurs if the island distance setting is large, where "large" means the server can't regenerate the chunks fast enough.

Quick workarounds that should help (stop the server before changing settings):

1. Turn off the Nether roof (in BSkyBlock/AcidIsland's config.yml) i.e., set it to false.
2. Reduce the island distance setting (not an option if you are mid-game)

Real fix - We'll work on this but we need to move the island deletion code into a periodic "async" deletion approach that does a few chunks at a time so the server doesn't timeout. That'll have some knock-on effects that we'll have to account for, such as not placing a new island in the location being deleted until it is fully deleted.