MC-9886Maps in item frames cause un-necessary lag
Currently, EntityTrackerEntry.track when sending map data for item frames is sending the data to all players in the same world.
Theres 2 issues:
1) The code is using the supplied "list" parameter passed to .track() which includes every player in the current world.
It should actually be using this.trackedPlayers, so that only players in range of the itemframe will receive the data.
2) It is checking the low priority queue for load, which is not used anymore so will always be true.
So on a large server, a single user can setup a large number of maps in item frames and totally destroy the servers performance as it spams the map data to every player in the world.
The main issue can be fixed by simply with CraftBukkit naming:
diff --git a/src/main/java/net/minecraft/server/EntityTrackerEntry.java b/src/main/java/net/minecraft/server/EntityTrackerEntry.java index c629046..f482f34 100644 --- a/src/main/java/net/minecraft/server/EntityTrackerEntry.java +++ b/src/main/java/net/minecraft/server/EntityTrackerEntry.java @@ -80,7 +80,7 @@ public class EntityTrackerEntry { if (i5 != null && i5.getItem() instanceof ItemWorldMap) { WorldMap i7 = Item.MAP.getSavedMap(i5, this.tracker.world); - Iterator j0 = list.iterator(); + Iterator j0 = this.trackedPlayers.iterator(); // CraftBukkit - Only send to players in range
Linked Issues
Created Issue:
Maps in item frames cause un-necessary lag and can be used to grief servers.
Currently, EntityTrackerEntry.track when sending map data for item frames is sending the data to all players in the same world.
Theres 2 issues:
1) The code is using the supplied "list" parameter passed to .track() which includes every player in the current world.It should actually be using this.trackedPlayers, so that only players in range of the itemframe will receive the data.
2) It is checking the low priority queue for load, which is not used anymore so will always be true.
So on a large server, a single user can setup a large number of maps in item frames and totally destroy the servers performance as it spams the map data to every player in the world.
The main issue can be fixed by simply with CraftBukkit naming:
diff --git a/src/main/java/net/minecraft/server/EntityTrackerEntry.java b/src/main/java/net/minecraft/server/EntityTrackerEntry.java index c629046..f482f34 100644 --- a/src/main/java/net/minecraft/server/EntityTrackerEntry.java +++ b/src/main/java/net/minecraft/server/EntityTrackerEntry.java @@ -80,7 +80,7 @@ public class EntityTrackerEntry { if (i5 != null && i5.getItem() instanceof ItemWorldMap) { WorldMap i7 = Item.MAP.getSavedMap(i5, this.tracker.world); - Iterator j0 = list.iterator(); + Iterator j0 = this.trackedPlayers.iterator(); // CraftBukkit - Only send to players in range
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duplicates
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duplicates
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Maps in item frames cause un-necessary lagand can be used to grief servers.
Duplicate of
MC-1138. Please use the search function to check before posting in the future.I did, this is not a duplicate. Please reopen and raise the priority of this.
This issue has nothing to do with that issue. This is a server issue, that is a client issue.
This needs to be fixed for 1.5 so please open and get it pushed to proper people ASAP.
Also, I have found another issue in the code.
The boolean logic for the "is an item frame and once every 10 ticks" is broken.
The update counter is never incremented, so this code will run EVERY tick, not one in ten.
The code needs to look something like this:
Id also recommend lowering the default itemframe tracking range so that so many people arent tracking them so far away.... at distances they cant even see the things really.
I contributed to the Spigot project with this fix, and multiple server owners are now running this slightly modified (to only send the map once) with great results.
Previously this issue was tearing servers apart.
It needs to be fixed ASAP before its wide spread to the public that you can take down servers and waste massive amounts of bandwidth with very little effort.
I will re-open this, however note that all issues have the same priority, and this cannot be changed.
Is this still a concern in the current Minecraft version 1.7.2 / Launcher version 1.3.4 ? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.
This was not a duplicate of that issue, but this is likely improved slightly in 1.7.