From cdb7534af1e2b9eccff805ba33c17dbe7173b8bf Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Thu, 27 Aug 2015 01:15:02 -0400
Subject: [PATCH] Optimize Chunk Access

getting a loaded chunk is one of the most hottest pieces of code in the game.
getChunkAt is called for the same chunk multiple times in a row, often from getType();

Optimize this look up by using a Last Access cache.

diff --git a/src/main/java/net/minecraft/server/ChunkMap.java b/src/main/java/net/minecraft/server/ChunkMap.java
index 0c2386f5e..5757aa80f 100644
--- a/src/main/java/net/minecraft/server/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/ChunkMap.java
@@ -106,8 +106,22 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
             }
         }
 
+        // Paper start
+        if (lastChunkByPos != null && i == lastChunkByPos.chunkKey) {
+            lastChunkByPos = null;
+        }
         return chunk;
     }
+    private Chunk lastChunkByPos = null; // Paper
+
+    @Override
+    public Chunk get(long l) {
+        if (lastChunkByPos != null && l == lastChunkByPos.chunkKey) {
+            return lastChunkByPos;
+        }
+        return super.get(l);
+    }
+    // Paper end
 
     public Chunk a(Object object) {
         return this.a(((Long) object).longValue());
-- 
2.18.0