From 39097e7eef729fb5a6c9aa9d52b16ddb3ced4008 Mon Sep 17 00:00:00 2001
From: md_5 <git@md-5.net>
Date: Sun, 12 Jan 2014 21:07:18 +1100
Subject: [PATCH] Improve AutoSave Mechanism

The problem here is that MinecraftServer.save(..), will attempt to sleep whilst all pending chunks are written to disk.
however due to various and complicated bugs, it will wait for an incorrect amount of chunks, which may cause it to sleep for an overly long amount of time.

Instead we will mimic the save-all command in its behaviour, which is both safe and performant.

Also, only save modified chunks, or chunks with entities after 4 auto save passes

diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index f461f50..994903f 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -942,7 +942,7 @@ public class Chunk {
             if (this.r && this.world.getTime() != this.lastSaved || this.q) {
                 return true;
             }
-        } else if (this.r && this.world.getTime() >= this.lastSaved + 600L) {
+        } else if (this.r && this.world.getTime() >= this.lastSaved + MinecraftServer.getServer().autosavePeriod * 4) { // Spigot - Only save if we've passed 2 auto save intervals without modification
             return true;
         }
 
diff --git a/src/main/java/net/minecraft/server/ChunkProviderServer.java b/src/main/java/net/minecraft/server/ChunkProviderServer.java
index af77eef..975d666 100644
--- a/src/main/java/net/minecraft/server/ChunkProviderServer.java
+++ b/src/main/java/net/minecraft/server/ChunkProviderServer.java
@@ -323,7 +323,7 @@ public class ChunkProviderServer implements IChunkProvider {
                 this.saveChunk(chunk);
                 chunk.f(false);
                 ++i;
-                if (i == 24 && !flag) {
+                if (i == 24 && !flag && false) { // Spigot
                     return false;
                 }
             }
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 1244fbf..95b4d0f 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -653,7 +653,17 @@ public abstract class MinecraftServer implements Runnable, ICommandListener, IAs
             SpigotTimings.worldSaveTimer.startTiming(); // Spigot
             this.methodProfiler.a("save");
             this.v.savePlayers();
-            this.saveChunks(true);
+            // Spigot Start
+            // We replace this with saving each individual world as this.saveChunks(...) is broken,
+            // and causes the main thread to sleep for random amounts of time depending on chunk activity
+            // Also pass flag to only save modified chunks
+            server.playerCommandState = true;
+            for (World world : worlds) {
+                world.getWorld().save(false);
+            }
+            server.playerCommandState = false;
+            // this.saveChunks(true);
+            // Spigot End
             this.methodProfiler.b();
             SpigotTimings.worldSaveTimer.stopTiming(); // Spigot
         }
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 20e2416..0629805 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -740,12 +740,17 @@ public class CraftWorld implements World {
     }
 
     public void save() {
+    // Spigot start
+        save(true);
+    }
+    public void save(boolean forceSave) {
+    // Spigot end
         this.server.checkSaveState();
         try {
             boolean oldSave = world.savingDisabled;
 
             world.savingDisabled = false;
-            world.save(true, null);
+            world.save(forceSave, null); // Spigot
 
             world.savingDisabled = oldSave;
         } catch (ExceptionWorldConflict ex) {
-- 
2.1.4