Paper/patches/server/0456-incremental-chunk-saving.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Sun, 9 Jun 2019 03:53:22 +0100
Subject: [PATCH] incremental chunk saving


diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 9e5810eb0085ad956f0bd1cd69fa88909d9d638a..77e90a6b7d29ad989fd961e00a6fd97c7e5ec4fe 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -44,6 +44,21 @@ public class PaperWorldConfig {
         log( "Keep Spawn Loaded Range: " + (keepLoadedRange/16));
     }
 
+    public int autoSavePeriod = -1;
+    private void autoSavePeriod() {
+        autoSavePeriod = getInt("auto-save-interval", -1);
+        if (autoSavePeriod > 0) {
+            log("Auto Save Interval: " +autoSavePeriod + " (" + (autoSavePeriod / 20) + "s)");
+        } else if (autoSavePeriod < 0) {
+            autoSavePeriod = net.minecraft.server.MinecraftServer.getServer().autosavePeriod;
+        }
+    }
+
+    public int maxAutoSaveChunksPerTick = 24;
+    private void maxAutoSaveChunksPerTick() {
+        maxAutoSaveChunksPerTick = getInt("max-auto-save-chunks-per-tick", 24);
+    }
+
     private boolean getBoolean(String path, boolean def) {
         config.addDefault("world-settings.default." + path, def);
         return config.getBoolean("world-settings." + worldName + "." + path, config.getBoolean("world-settings.default." + path));
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index d285967a60903a73608a1f9cdc306e63066824ab..a36fa61313baf9ab260b8805860ac4bce24bc3c6 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -296,6 +296,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
     public static int currentTick = 0; // Paper - Further improve tick loop
     public java.util.Queue<Runnable> processQueue = new java.util.concurrent.ConcurrentLinkedQueue<Runnable>();
     public int autosavePeriod;
+    public boolean serverAutoSave = false; // Paper
     public Commands vanillaCommandDispatcher;
     public boolean forceTicks; // Paper
     // CraftBukkit end
@@ -1413,14 +1414,23 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
             this.status.getPlayers().setSample(agameprofile);
         }
 
-        if (this.autosavePeriod > 0 && this.tickCount % this.autosavePeriod == 0) { // CraftBukkit
-            MinecraftServer.LOGGER.debug("Autosave started");
+        // if (this.autosavePeriod > 0 && this.tickCount % this.autosavePeriod == 0) { // CraftBukkit // Paper - move down
+        //     MinecraftServer.LOGGER.debug("Autosave started"); // Paper
+        serverAutoSave = (autosavePeriod > 0 && this.tickCount % autosavePeriod == 0); // Paper
             this.profiler.push("save");
+        if (this.autosavePeriod > 0 && this.tickCount % this.autosavePeriod == 0) { // Paper - moved from above
             this.playerList.saveAll();
-            this.saveAllChunks(true, false, false);
-            this.profiler.pop();
-            MinecraftServer.LOGGER.debug("Autosave finished");
+            // this.saveAllChunks(true, false, false); // Paper - saved incrementally below
+        } // Paper start
+        for (ServerLevel level : this.getAllLevels()) {
+            if (level.paperConfig.autoSavePeriod > 0) {
+                level.saveIncrementally(this.serverAutoSave);
+            }
         }
+        // Paper end
+            this.profiler.pop();
+            // MinecraftServer.LOGGER.debug("Autosave finished"); // Paper
+        //} // Paper
 
         this.profiler.push("snooper");
         if (((DedicatedServer) this).getProperties().snooperEnabled && !this.snooper.isStarted() && this.tickCount > 100) { // Spigot
diff --git a/src/main/java/net/minecraft/server/level/ChunkHolder.java b/src/main/java/net/minecraft/server/level/ChunkHolder.java
index e6883cad6c604673535deacc19463aeeb060199a..e26b65c3b2594ae45b68bcbd135152130663be7f 100644
--- a/src/main/java/net/minecraft/server/level/ChunkHolder.java
+++ b/src/main/java/net/minecraft/server/level/ChunkHolder.java
@@ -111,6 +111,8 @@ public class ChunkHolder {
         this.playersInChunkTickRange = this.chunkMap.playerChunkTickRangeMap.getObjectsInRange(key);
     }
     // Paper end - optimise isOutsideOfRange
+    long lastAutoSaveTime; // Paper - incremental autosave
+    long inactiveTimeStart; // Paper - incremental autosave
 
     public ChunkHolder(ChunkPos pos, int level, LevelHeightAccessor world, LevelLightEngine lightingProvider, ChunkHolder.LevelChangeListener levelUpdateListener, ChunkHolder.PlayerProvider playersWatchingChunkProvider) {
         this.futures = new AtomicReferenceArray(ChunkHolder.CHUNK_STATUSES.size());
@@ -524,7 +526,19 @@ public class ChunkHolder {
         boolean flag2 = playerchunk_state.isOrAfter(ChunkHolder.FullChunkStatus.BORDER);
         boolean flag3 = playerchunk_state1.isOrAfter(ChunkHolder.FullChunkStatus.BORDER);
 
+        boolean prevHasBeenLoaded = this.wasAccessibleSinceLastSave; // Paper
         this.wasAccessibleSinceLastSave |= flag3;
+        // Paper start - incremental autosave
+        if (this.wasAccessibleSinceLastSave & !prevHasBeenLoaded) {
+            long timeSinceAutoSave = this.inactiveTimeStart - this.lastAutoSaveTime;
+            if (timeSinceAutoSave < 0) {
+                // safest bet is to assume autosave is needed here
+                timeSinceAutoSave = this.chunkMap.level.paperConfig.autoSavePeriod;
+            }
+            this.lastAutoSaveTime = this.chunkMap.level.getGameTime() - timeSinceAutoSave;
+            this.chunkMap.autoSaveQueue.add(this);
+        }
+        // Paper end
         if (!flag2 && flag3) {
             int expectCreateCount = ++this.fullChunkCreateCount; // Paper
             this.fullChunkFuture = chunkStorage.prepareAccessibleChunk(this);
@@ -645,9 +659,33 @@ public class ChunkHolder {
     }
 
     public void refreshAccessibility() {
+        boolean prev = this.wasAccessibleSinceLastSave; // Paper
         this.wasAccessibleSinceLastSave = ChunkHolder.getFullChunkStatus(this.ticketLevel).isOrAfter(ChunkHolder.FullChunkStatus.BORDER);
+        // Paper start - incremental autosave
+        if (prev != this.wasAccessibleSinceLastSave) {
+            if (this.wasAccessibleSinceLastSave) {
+                long timeSinceAutoSave = this.inactiveTimeStart - this.lastAutoSaveTime;
+                if (timeSinceAutoSave < 0) {
+                    // safest bet is to assume autosave is needed here
+                    timeSinceAutoSave = this.chunkMap.level.paperConfig.autoSavePeriod;
+                }
+                this.lastAutoSaveTime = this.chunkMap.level.getGameTime() - timeSinceAutoSave;
+                this.chunkMap.autoSaveQueue.add(this);
+            } else {
+                this.inactiveTimeStart = this.chunkMap.level.getGameTime();
+                this.chunkMap.autoSaveQueue.remove(this);
+            }
+        }
+        // Paper end
     }
 
+    // Paper start - incremental autosave
+    public boolean setHasBeenLoaded() {
+        this.wasAccessibleSinceLastSave = getFullChunkStatus(this.ticketLevel).isOrAfter(ChunkHolder.FullChunkStatus.BORDER);
+        return this.wasAccessibleSinceLastSave;
+    }
+    // Paper end
+
     public void replaceProtoChunk(ImposterProtoChunk chunk) {
         for (int i = 0; i < this.futures.length(); ++i) {
             CompletableFuture<Either<ChunkAccess, ChunkHolder.ChunkLoadingFailure>> completablefuture = (CompletableFuture) this.futures.get(i);
diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index a1529fef41543486d29271b1de62a6246d07d384..f518fc7a39a807bff2e141fd238ab1bfc34ce890 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -97,6 +97,7 @@ import net.minecraft.world.level.levelgen.structure.templatesystem.StructureMana
 import net.minecraft.world.level.storage.DimensionDataStorage;
 import net.minecraft.world.level.storage.LevelStorageSource;
 import net.minecraft.world.phys.Vec3;
+import it.unimi.dsi.fastutil.objects.ObjectRBTreeSet; // Paper
 import org.apache.commons.lang3.mutable.MutableBoolean;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -750,6 +751,64 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
 
     }
 
+    // Paper start - incremental autosave
+    final ObjectRBTreeSet<ChunkHolder> autoSaveQueue = new ObjectRBTreeSet<>((playerchunk1, playerchunk2) -> {
+        int timeCompare =  Long.compare(playerchunk1.lastAutoSaveTime, playerchunk2.lastAutoSaveTime);
+        if (timeCompare != 0) {
+            return timeCompare;
+        }
+
+        return Long.compare(MCUtil.getCoordinateKey(playerchunk1.pos), MCUtil.getCoordinateKey(playerchunk2.pos));
+    });
+
+    protected void saveIncrementally() {
+        int savedThisTick = 0;
+        // optimized since we search far less chunks to hit ones that need to be saved
+        List<ChunkHolder> reschedule = new java.util.ArrayList<>(this.level.paperConfig.maxAutoSaveChunksPerTick);
+        long currentTick = this.level.getGameTime();
+        long maxSaveTime = currentTick - this.level.paperConfig.autoSavePeriod;
+
+        for (Iterator<ChunkHolder> iterator = this.autoSaveQueue.iterator(); iterator.hasNext();) {
+            ChunkHolder playerchunk = iterator.next();
+            if (playerchunk.lastAutoSaveTime > maxSaveTime) {
+                break;
+            }
+
+            iterator.remove();
+
+            ChunkAccess ichunkaccess = playerchunk.getChunkToSave().getNow(null);
+            if (ichunkaccess instanceof LevelChunk) {
+                boolean shouldSave = ((LevelChunk)ichunkaccess).lastSaveTime <= maxSaveTime;
+
+                if (shouldSave && this.save(ichunkaccess) && this.level.entityManager.storeChunkSections(playerchunk.pos.toLong(), entity -> {})) {
+                    ++savedThisTick;
+
+                    if (!playerchunk.setHasBeenLoaded()) {
+                        // do not fall through to reschedule logic
+                        playerchunk.inactiveTimeStart = currentTick;
+                        if (savedThisTick >= this.level.paperConfig.maxAutoSaveChunksPerTick) {
+                            break;
+                        }
+                        continue;
+                    }
+                }
+            }
+
+            reschedule.add(playerchunk);
+
+            if (savedThisTick >= this.level.paperConfig.maxAutoSaveChunksPerTick) {
+                break;
+            }
+        }
+
+        for (int i = 0, len = reschedule.size(); i < len; ++i) {
+            ChunkHolder playerchunk = reschedule.get(i);
+            playerchunk.lastAutoSaveTime = this.level.getGameTime();
+            this.autoSaveQueue.add(playerchunk);
+        }
+    }
+    // Paper end
+
     protected void saveAllChunks(boolean flush) {
         Long2ObjectLinkedOpenHashMap<ChunkHolder> visibleChunks = this.getVisibleChunks(); // Paper remove clone of visible Chunks unless saving off main thread (watchdog kill)
         if (flush) {
@@ -888,6 +947,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
             asyncSaveData, chunk);
 
         chunk.setUnsaved(false);
+        chunk.setLastSaved(this.level.getGameTime()); // Paper - track last saved time
     }
     // Paper end
 
@@ -919,6 +979,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
 
                         this.level.unload(chunk);
                     }
+                    this.autoSaveQueue.remove(holder); // Paper
 
                     this.lightEngine.updateChunkStatus(ichunkaccess.getPos());
                     this.lightEngine.tryScheduleUpdate();
@@ -1272,6 +1333,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
         if (!chunk.isUnsaved()) {
             return false;
         } else {
+            chunk.setLastSaved(this.level.getGameTime()); // Paper - track save time
             chunk.setUnsaved(false);
             ChunkPos chunkcoordintpair = chunk.getPos();
 
diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index d8bf5a86a3eb0ae3fd6308e817a707ae98961479..ec0a9f46b50280324ae0d2eed208c8f332a5d88d 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -671,6 +671,15 @@ public class ServerChunkCache extends ChunkSource {
         } // Paper - Timings
     }
 
+    // Paper start - duplicate save, but call incremental
+    public void saveIncrementally() {
+        this.runDistanceManagerUpdates();
+        try (co.aikar.timings.Timing timed = level.timings.chunkSaveData.startTiming()) { // Paper - Timings
+            this.chunkMap.saveIncrementally();
+        } // Paper - Timings
+    }
+    // Paper end
+
     @Override
     public void close() throws IOException {
         // CraftBukkit start
diff --git a/src/main/java/net/minecraft/server/level/ServerLevel.java b/src/main/java/net/minecraft/server/level/ServerLevel.java
index 79338bd6349b1e454f190e4daab030859d5fdf47..15d27aa11594b668ca7715ed1c465c6003d6e9bf 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -964,6 +964,37 @@ public class ServerLevel extends Level implements WorldGenLevel {
         return !this.server.isUnderSpawnProtection(this, pos, player) && this.getWorldBorder().isWithinBounds(pos);
     }
 
+    // Paper start - derived from below
+    public void saveIncrementally(boolean doFull) {
+        ServerChunkCache chunkproviderserver = this.getChunkSource();
+
+        if (doFull) {
+            org.bukkit.Bukkit.getPluginManager().callEvent(new org.bukkit.event.world.WorldSaveEvent(getWorld()));
+        }
+
+        try (co.aikar.timings.Timing ignored = this.timings.worldSave.startTiming()) {
+            if (doFull) {
+                this.saveLevelData();
+            }
+
+            this.timings.worldSaveChunks.startTiming(); // Paper
+            if (!this.noSave()) chunkproviderserver.saveIncrementally();
+            this.timings.worldSaveChunks.stopTiming(); // Paper
+
+            // Copied from save()
+            // CraftBukkit start - moved from MinecraftServer.saveChunks
+            if (doFull) { // Paper
+                ServerLevel worldserver1 = this;
+
+                this.serverLevelData.setWorldBorder(worldserver1.getWorldBorder().createSettings());
+                this.serverLevelData.setCustomBossEvents(this.server.getCustomBossEvents().save());
+                this.convertable.saveDataTag(this.server.registryHolder, this.serverLevelData, this.server.getPlayerList().getSingleplayerData());
+            }
+            // CraftBukkit end
+        }
+    }
+    // Paper end
+
     public void save(@Nullable ProgressListener progressListener, boolean flush, boolean flag1) {
         ServerChunkCache chunkproviderserver = this.getChunkSource();
 
diff --git a/src/main/java/net/minecraft/world/level/chunk/ChunkAccess.java b/src/main/java/net/minecraft/world/level/chunk/ChunkAccess.java
index 12d11a249c759e99568a76c791cc0d65adfcfe94..8393950a0b38ec7897d7643803d5accdb1f983f3 100644
--- a/src/main/java/net/minecraft/world/level/chunk/ChunkAccess.java
+++ b/src/main/java/net/minecraft/world/level/chunk/ChunkAccess.java
@@ -29,6 +29,7 @@ public interface ChunkAccess extends BlockGetter, FeatureAccess {
         return GameEventDispatcher.NOOP;
     }
 
+    default void setLastSaved(long ticks) {}
     // Paper start
     default boolean generateFlatBedrock() {
         if (this.getLevel() != null) {
diff --git a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
index 7d33ad1ec939de4527d0acb0915f05870c387565..cc02b577453fa251f0f1b508281ddea2513138a1 100644
--- a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
+++ b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
@@ -108,6 +108,13 @@ public class LevelChunk implements ChunkAccess {
     private final ShortList[] postProcessing;
     private TickList<Block> blockTicks;
     private TickList<Fluid> liquidTicks;
+    // Paper start - track last save time
+    public long lastSaveTime;
+    @Override
+    public void setLastSaved(long ticks) {
+        this.lastSaveTime = ticks;
+    }
+    // Paper end
     private volatile boolean unsaved;
     private long inhabitedTime;
     @Nullable