CraftBukkit added synchronization to read and write methods. This adds
much more contention on this object for accessing region files, as
the entire read and write of NBT data is now a blocking operation.
This causes issues when something then simply needs to check if a chunk exists
on the main thread, causing a block...
However, this synchronization was unnecessary, because there is already
enough synchronization done to keep things safe
1) Obtaining a Region File: Those methods are still static synchronized.
Meaning we can safely obtain a Region File concurrently.
2) RegionFile data access: Methods reading and manipulating data from
a region file are also marked synchronized, ensuring that no 2 processes
are reading or writing data at the same time.
3) Checking a region file for chunkExists: getOffset is also synchronized
ensuring that even if a chunk is currently being written, it will be safe.
By removing these synchronizations, we reduce the locking to only
when data is being write or read.
GZIP compression and NBT Buffer creation will no longer be part of the
synchronized context, reducing lock times.
Ultimately: This brings us back to Vanilla, which has had no indication of region file loss.
Closes#1260
* master:
Add some debug for entity slices
Mark chunk dirty on entity changes
Reduce and improve dupe uuid resolve message
Add more entity debug info
Bring some 1.13 authors to master
Fixed more stuff
Remove unsed method
Extend player profile API to support skin changes
Extend player profile API to support skin changes
Cleaned up some implementation notes to use existing Vanilla method for some things.
merged into parent patch
9526c764 Fixed more stuff (NickAcPT)
8672424c Remove unsed method (NickAcPT)
a7f45fb1 Extend player profile API to support skin changes (NickAcPT)
4cccd48a Extend player profile API to support skin changes (NickAcPT)
* pull/1250/head:
Fixed more stuff
Remove unsed method
Extend player profile API to support skin changes
Extend player profile API to support skin changes
5e14f241 Put the decompile fixes into MC Dev Fixes patch (Andrew Steinborn)
9399a74c Optimize RegistryID.c() (Andrew Steinborn)
* pull/1257/head:
Put the decompile fixes into MC Dev Fixes patch
Optimize RegistryID.c()
It's possible we won't hit this on the servers current state since nothing is async,
but we are working towards that.
I experienced a crash due to this code during my work.
Our changes for the spawn radius have the potential to throw an ArithmeticException
should the server be stopped before we've loaded worlds, we check if the server is
running earlier to check if we should even consider attempting to load chunks, which
would cause us to, 1) not load chunks anyways, as we're disabled; 2) throw an
ArithmeticException due to us expecting that we're going to be loading more than 0 chunks.
These chunks are unfinished, and waste cpu time saving these unfinished chunks.
the loadChunk method refuses to acknoledge they exists, and will restart
a new chunk generation process to begin with, so saving them serves no benefit.
* master:
Duplicate UUID Resolve Option
Add more information to Entity.toString
change LAST_EDIT to PAPER_LAST_EDIT for edit commands
Add more information to Entity.toString()
Add Debug Entities option to debug dupe uuid issues
Guard the Entity.SHARED_RANDOM from seed changes
Create a symlink on not-windows to current minecraft decompile dir
Due to a bug in bd75ff8b5b
which was added all the way back in March of 2016, it was unknown (potentially not at the time)
that an entity might actually change the seed of the random object.
At some point, EntitySquid did start setting the seed. Due to this shared random, this caused
every entity to use a Random object with a predictable seed.
This has caused entities to potentially generate with the same UUID....
Over the years, servers have had entities disappear, but no sign of trouble
because CraftBukkit removed the log lines indicating that something was wrong.
We have fixed the root issue causing duplicate UUID's, however we now have chunk
files full of entities that have the same UUID as another entity!
When these chunks load, the 2nd entity will not be added to the world correctly.
If that chunk loads in a different order in the future, then it will reverse and the
missing one is now the one added to the world and not the other. This results in very
inconsistent entity behavior.
This change allows you to recover any duplicate entity by generating a new UUID for it.
This also lets you delete them instead if you don't want to risk having new entities added to
the world that you previously did not see.
But for those who are ok with leaving this inconsistent behavior, you may use WARN or NOTHING options.
It is recommended you regenerate the entities, as these were legit entities, and deserve your love.
