Ходосова Елена, ИТМО DWS, Stage 6

src/main/java/ru/vk/itmo/test/elenakhodosova/Server.java

@@ -12,6 +12,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
@@ -29,6 +30,7 @@ private Server() {
 
     public static void main(String[] args) throws IOException {
         List<ServiceConfig> nodesConfigs = new ArrayList<>(NODES_COUNT);
+        ExecutorService executorService = ExecutorServiceConfig.newExecutorService();
 
         Map<Integer, String> nodes = new HashMap<>();
         int nodePort = 8080;
@@ -50,12 +52,14 @@ public static void main(String[] args) throws IOException {
         }
         for (ServiceConfig config : nodesConfigs) {
             ServiceImpl server = new ServiceImpl(config);
-            try {
-                server.start().get(1, TimeUnit.SECONDS);
-            } catch (InterruptedException | ExecutionException | TimeoutException e) {
-                logger.error("Unable to start service instance: ", e);
-                Thread.currentThread().interrupt();
-            }
+            executorService.execute(() -> {
+                try {
+                    server.start().get(1, TimeUnit.SECONDS);
+                } catch (InterruptedException | ExecutionException | TimeoutException | IOException e) {
+                    logger.error("Unable to start service instance: ", e);
+                    Thread.currentThread().interrupt();
+                }
+            });
         }
     }
 }

src/main/java/ru/vk/itmo/test/elenakhodosova/ServiceImpl.java

@@ -33,11 +33,12 @@ public CompletableFuture<Void> start() throws IOException {
         executorService = ExecutorServiceConfig.newExecutorService();
         server = new HttpServerImpl(config, dao, executorService);
         server.start();
+        isServiceStopped.getAndSet(false);
         return CompletableFuture.completedFuture(null);
     }
 
     @Override
-    public CompletableFuture<Void> stop() throws IOException {
+    public synchronized CompletableFuture<Void> stop() throws IOException {
         if (isServiceStopped.getAndSet(true)) {
             return CompletableFuture.completedFuture(null);
         }
@@ -48,13 +49,14 @@ public CompletableFuture<Void> stop() throws IOException {
                 executorService.shutdownNow();
             }
         } catch (InterruptedException e) {
+            executorService.shutdownNow();
             Thread.currentThread().interrupt();
         }
         dao.close();
         return CompletableFuture.completedFuture(null);
     }
 
-    @ServiceFactory(stage = 3)
+    @ServiceFactory(stage = 6)
     public static class Factory implements ServiceFactory.Factory {
 
         @Override

src/main/java/ru/vk/itmo/test/elenakhodosova/dao/BaseEntryWithTimestamp.java

@@ -0,0 +1,8 @@
+package ru.vk.itmo.test.elenakhodosova.dao;
+
+public record BaseEntryWithTimestamp<Data>(Data key, Data value, long timestamp) implements EntryWithTimestamp<Data> {
+    @Override
+    public String toString() {
+        return "{" + key + ":" + value + ":" + timestamp + "}";
+    }
+}

src/main/java/ru/vk/itmo/test/elenakhodosova/dao/EntryWithTimestamp.java

@@ -0,0 +1,7 @@
+package ru.vk.itmo.test.elenakhodosova.dao;
+
+import ru.vk.itmo.dao.Entry;
+
+public interface EntryWithTimestamp<D> extends Entry<D> {
+    long timestamp();
+}

src/main/java/ru/vk/itmo/test/elenakhodosova/dao/LiveFilteringIterator.java

@@ -1,28 +1,26 @@
 package ru.vk.itmo.test.elenakhodosova.dao;
 
-import ru.vk.itmo.dao.Entry;
-
 import java.lang.foreign.MemorySegment;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
 
 /**
- * Filters non tombstone {@link Entry}s.
+ * Filters non tombstone {@link EntryWithTimestamp}s.
  *
  * @author incubos
  */
-final class LiveFilteringIterator implements Iterator<Entry<MemorySegment>> {
-    private final Iterator<Entry<MemorySegment>> delegate;
-    private Entry<MemorySegment> next;
+final class LiveFilteringIterator implements Iterator<EntryWithTimestamp<MemorySegment>> {
+    private final Iterator<EntryWithTimestamp<MemorySegment>> delegate;
+    private EntryWithTimestamp<MemorySegment> next;
 
-    LiveFilteringIterator(final Iterator<Entry<MemorySegment>> delegate) {
+    LiveFilteringIterator(final Iterator<EntryWithTimestamp<MemorySegment>> delegate) {
         this.delegate = delegate;
         skipTombstones();
     }
 
     private void skipTombstones() {
         while (delegate.hasNext()) {
-            final Entry<MemorySegment> entry = delegate.next();
+            final EntryWithTimestamp<MemorySegment> entry = delegate.next();
             if (entry.value() != null) {
                 this.next = entry;
                 break;
@@ -36,13 +34,13 @@ public boolean hasNext() {
     }
 
     @Override
-    public Entry<MemorySegment> next() {
+    public EntryWithTimestamp<MemorySegment> next() {
         if (!hasNext()) {
             throw new NoSuchElementException();
         }
 
         // Consume
-        final Entry<MemorySegment> result = next;
+        final EntryWithTimestamp<MemorySegment> result = next;
         next = null;
 
         skipTombstones();

src/main/java/ru/vk/itmo/test/elenakhodosova/dao/MemTable.java

@@ -1,7 +1,5 @@
 package ru.vk.itmo.test.elenakhodosova.dao;
 
-import ru.vk.itmo.dao.Entry;
-
 import java.lang.foreign.MemorySegment;
 import java.util.Iterator;
 import java.util.NavigableMap;
@@ -13,15 +11,15 @@
  * @author incubos
  */
 final class MemTable {
-    private final NavigableMap<MemorySegment, Entry<MemorySegment>> map =
+    private final NavigableMap<MemorySegment, EntryWithTimestamp<MemorySegment>> map =
             new ConcurrentSkipListMap<>(
                     MemorySegmentComparator.INSTANCE);
 
     boolean isEmpty() {
         return map.isEmpty();
     }
 
-    Iterator<Entry<MemorySegment>> get(
+    Iterator<EntryWithTimestamp<MemorySegment>> get(
             final MemorySegment from,
             final MemorySegment to) {
         if (from == null && to == null) {
@@ -39,11 +37,11 @@ Iterator<Entry<MemorySegment>> get(
         }
     }
 
-    Entry<MemorySegment> get(final MemorySegment key) {
+    EntryWithTimestamp<MemorySegment> get(final MemorySegment key) {
         return map.get(key);
     }
 
-    Entry<MemorySegment> upsert(final Entry<MemorySegment> entry) {
+    EntryWithTimestamp<MemorySegment> upsert(final EntryWithTimestamp<MemorySegment> entry) {
         return map.put(entry.key(), entry);
     }
 }

src/main/java/ru/vk/itmo/test/elenakhodosova/dao/MergingEntryIterator.java

@@ -1,7 +1,5 @@
 package ru.vk.itmo.test.elenakhodosova.dao;
 
-import ru.vk.itmo.dao.Entry;
-
 import java.lang.foreign.MemorySegment;
 import java.util.Iterator;
 import java.util.List;
@@ -14,7 +12,7 @@
  *
  * @author incubos
  */
-final class MergingEntryIterator implements Iterator<Entry<MemorySegment>> {
+final class MergingEntryIterator implements Iterator<EntryWithTimestamp<MemorySegment>> {
     private final Queue<WeightedPeekingEntryIterator> iterators;
 
     MergingEntryIterator(final List<WeightedPeekingEntryIterator> iterators) {
@@ -29,13 +27,13 @@ public boolean hasNext() {
     }
 
     @Override
-    public Entry<MemorySegment> next() {
+    public EntryWithTimestamp<MemorySegment> next() {
         if (!hasNext()) {
             throw new NoSuchElementException();
         }
 
         final WeightedPeekingEntryIterator top = iterators.remove();
-        final Entry<MemorySegment> result = top.next();
+        final EntryWithTimestamp<MemorySegment> result = top.next();
 
         if (top.hasNext()) {
             // Not exhausted
@@ -51,7 +49,7 @@ public Entry<MemorySegment> next() {
             }
 
             // Skip entries with the same key
-            final Entry<MemorySegment> entry = iterator.peek();
+            final EntryWithTimestamp<MemorySegment> entry = iterator.peek();
             if (MemorySegmentComparator.INSTANCE.compare(result.key(), entry.key()) != 0) {
                 // Reached another key
                 break;

src/main/java/ru/vk/itmo/test/elenakhodosova/dao/ReferenceDao.java

@@ -2,7 +2,6 @@
 
 import ru.vk.itmo.dao.Config;
 import ru.vk.itmo.dao.Dao;
-import ru.vk.itmo.dao.Entry;
 
 import java.io.IOException;
 import java.lang.foreign.Arena;
@@ -22,7 +21,7 @@
  *
  * @author incubos
  */
-public class ReferenceDao implements Dao<MemorySegment, Entry<MemorySegment>> {
+public class ReferenceDao implements Dao<MemorySegment, EntryWithTimestamp<MemorySegment>> {
     private final Config config;
     private final Arena arena;
 
@@ -63,7 +62,7 @@ public ReferenceDao(final Config config) throws IOException {
     }
 
     @Override
-    public Iterator<Entry<MemorySegment>> get(
+    public Iterator<EntryWithTimestamp<MemorySegment>> get(
             final MemorySegment from,
             final MemorySegment to) {
         return new LiveFilteringIterator(
@@ -73,13 +72,13 @@ public Iterator<Entry<MemorySegment>> get(
     }
 
     @Override
-    public Entry<MemorySegment> get(final MemorySegment key) {
+    public EntryWithTimestamp<MemorySegment> get(final MemorySegment key) {
         // Without lock, just snapshot of table set
         return tableSet.get(key);
     }
 
     @Override
-    public void upsert(final Entry<MemorySegment> entry) {
+    public void upsert(final EntryWithTimestamp<MemorySegment> entry) {
         final boolean autoFlush;
         lock.readLock().lock();
         try {
@@ -89,7 +88,7 @@ public void upsert(final Entry<MemorySegment> entry) {
             }
 
             // Upsert
-            final Entry<MemorySegment> previous = tableSet.upsert(entry);
+            final EntryWithTimestamp<MemorySegment> previous = tableSet.upsert(entry);
 
             // Update size estimate
             final long size = tableSet.memTableSize.addAndGet(sizeOf(entry) - sizeOf(previous));
@@ -103,16 +102,16 @@ public void upsert(final Entry<MemorySegment> entry) {
         }
     }
 
-    private static long sizeOf(final Entry<MemorySegment> entry) {
+    private static long sizeOf(final EntryWithTimestamp<MemorySegment> entry) {
         if (entry == null) {
             return 0L;
         }
 
         if (entry.value() == null) {
-            return entry.key().byteSize();
+            return entry.key().byteSize() + Long.BYTES;
         }
 
-        return entry.key().byteSize() + entry.value().byteSize();
+        return entry.key().byteSize() + entry.value().byteSize() + Long.BYTES;
     }
 
     private void initiateFlush(final boolean auto) {
@@ -200,8 +199,7 @@ public void compact() throws IOException {
                         .write(
                                 config.basePath(),
                                 0,
-                                new LiveFilteringIterator(
-                                        currentTableSet.allSSTableEntries()));
+                                new LiveFilteringIterator(currentTableSet.allSSTableEntries()));
             } catch (IOException e) {
                 e.printStackTrace();
                 Runtime.getRuntime().halt(-3);

src/main/java/ru/vk/itmo/test/elenakhodosova/dao/SSTable.java

@@ -1,8 +1,5 @@
 package ru.vk.itmo.test.elenakhodosova.dao;
 
-import ru.vk.itmo.dao.BaseEntry;
-import ru.vk.itmo.dao.Entry;
-
 import java.lang.foreign.MemorySegment;
 import java.lang.foreign.ValueLayout;
 import java.util.Collections;
@@ -88,7 +85,7 @@ private long getLength(final long offset) {
                 offset);
     }
 
-    Iterator<Entry<MemorySegment>> get(
+    Iterator<EntryWithTimestamp<MemorySegment>> get(
             final MemorySegment from,
             final MemorySegment to) {
         assert from == null || to == null || MemorySegmentComparator.INSTANCE.compare(from, to) <= 0;
@@ -134,7 +131,7 @@ Iterator<Entry<MemorySegment>> get(
         return new SliceIterator(fromOffset, toOffset);
     }
 
-    Entry<MemorySegment> get(final MemorySegment key) {
+    EntryWithTimestamp<MemorySegment> get(final MemorySegment key) {
         final long entry = entryBinarySearch(key);
         if (entry < 0) {
             return null;
@@ -146,17 +143,24 @@ Entry<MemorySegment> get(final MemorySegment key) {
         // Extract value length
         final long valueLength = getLength(offset);
         if (valueLength == SSTables.TOMBSTONE_VALUE_LENGTH) {
+            // Get timestamp
+            offset += Long.BYTES;
+            final long timestamp = getLength(offset);
             // Tombstone encountered
-            return new BaseEntry<>(key, null);
+            return new BaseEntryWithTimestamp<>(key, null, timestamp);
         } else {
             // Get value
             offset += Long.BYTES;
             final MemorySegment value = data.asSlice(offset, valueLength);
-            return new BaseEntry<>(key, value);
+
+            // Get timestamp
+            offset += valueLength;
+            final long timestamp = getLength(offset);
+            return new BaseEntryWithTimestamp<>(key, value, timestamp);
         }
     }
 
-    private final class SliceIterator implements Iterator<Entry<MemorySegment>> {
+    private final class SliceIterator implements Iterator<EntryWithTimestamp<MemorySegment>> {
         private long offset;
         private final long toOffset;
 
@@ -173,7 +177,7 @@ public boolean hasNext() {
         }
 
         @Override
-        public Entry<MemorySegment> next() {
+        public EntryWithTimestamp<MemorySegment> next() {
             if (!hasNext()) {
                 throw new NoSuchElementException();
             }
@@ -193,11 +197,15 @@ public Entry<MemorySegment> next() {
             // Read value
             if (valueLength == SSTables.TOMBSTONE_VALUE_LENGTH) {
                 // Tombstone encountered
-                return new BaseEntry<>(key, null);
+                final long timestamp = getLength(offset);
+                offset += Long.BYTES;
+                return new BaseEntryWithTimestamp<>(key, null, timestamp);
             } else {
                 final MemorySegment value = data.asSlice(offset, valueLength);
                 offset += valueLength;
-                return new BaseEntry<>(key, value);
+                final long timestamp = getLength(offset);
+                offset += Long.BYTES;
+                return new BaseEntryWithTimestamp<>(key, value, timestamp);
             }
         }
     }