fix not call access() when size > halfCapacity

Change-Id: Ic613f1d387dae26cc3cd6b69346d28a912453f72
apache · Jun 24, 2021 · 0dfc5e9 · 0dfc5e9
1 parent f2549da
commit 0dfc5e9
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Showing 2 changed files with 12 additions and 21 deletions.
diff --git a/hugegraph-core/src/main/java/com/baidu/hugegraph/backend/cache/AbstractCache.java b/hugegraph-core/src/main/java/com/baidu/hugegraph/backend/cache/AbstractCache.java
@@ -47,7 +47,6 @@ public abstract class AbstractCache<K, V> implements Cache<K, V> {
 
     // NOTE: the count in number of items, not in bytes
     private final long capacity;
-    private final long halfCapacity;
 
     // For user attachment
     private final AtomicReference<Object> attachment;
@@ -61,7 +60,6 @@ public AbstractCache(long capacity) {
             capacity = 0L;
         }
         this.capacity = capacity;
-        this.halfCapacity = this.capacity >> 1;
         this.attachment = new AtomicReference<>();
 
         this.expire = 0L;
@@ -77,15 +75,13 @@ public V get(K id) {
         if (id == null || this.capacity <= 0L) {
             return null;
         }
-        V value = null;
-        if (this.size() <= this.halfCapacity) {
-            // Maybe the id removed by other threads and returned null value
-            value = this.access(id);
-        }
+
+        V value = this.access(id);
 
         if (this.enabledMetrics) {
             this.collectMetrics(id, value);
         }
+
         return value;
     }
 
@@ -95,11 +91,8 @@ public V getOrFetch(K id, Function<K, V> fetcher) {
         if (id == null || this.capacity <= 0L) {
             return null;
         }
-        V value = null;
-        if (this.size() <= this.halfCapacity) {
-            // Maybe the id removed by other threads and returned null value
-            value = this.access(id);
-        }
+
+        V value = this.access(id);
 
         if (this.enabledMetrics) {
             this.collectMetrics(id, value);
@@ -247,10 +240,6 @@ public <T> T attachment() {
         return attachment;
     }
 
-    protected final long halfCapacity() {
-        return this.halfCapacity;
-    }
-
     protected abstract V access(K id);
 
     protected abstract boolean write(K id, V value, long timeOffset);

diff --git a/hugegraph-core/src/main/java/com/baidu/hugegraph/backend/cache/RamCache.java b/hugegraph-core/src/main/java/com/baidu/hugegraph/backend/cache/RamCache.java
@@ -39,6 +39,7 @@ public class RamCache extends AbstractCache<Id, Object> {
     private final LinkedQueueNonBigLock<Id, Object> queue;
 
     private final KeyLock keyLock;
+    private final long halfCapacity;
 
     public RamCache() {
         this(DEFAULT_SIZE);
@@ -47,11 +48,12 @@ public RamCache() {
     public RamCache(long capacity) {
         super(capacity);
 
-        this.keyLock = new KeyLock();
-
         if (capacity < 0L) {
             capacity = 0L;
         }
+        this.keyLock = new KeyLock();
+        this.halfCapacity = capacity >> 1;
+
         long initialCapacity = capacity >= MB ? capacity >> 10 : 256;
         if (initialCapacity > MAX_INIT_CAP) {
             initialCapacity = MAX_INIT_CAP;
@@ -66,8 +68,7 @@ public RamCache(long capacity) {
     protected final Object access(Id id) {
         assert id != null;
 
-        long halfCapacity = this.halfCapacity();
-        if (this.map.size() <= halfCapacity) {
+        if (this.map.size() <= this.halfCapacity) {
             LinkNode<Id, Object> node = this.map.get(id);
             if (node == null) {
                 return null;
@@ -83,13 +84,14 @@ protected final Object access(Id id) {
 
         final Lock lock = this.keyLock.lock(id);
         try {
+            // Maybe the id removed by other threads and returned null value
             LinkNode<Id, Object> node = this.map.get(id);
             if (node == null) {
                 return null;
             }
 
             // NOTE: update the queue only if the size > capacity/2
-            if (this.map.size() > halfCapacity) {
+            if (this.map.size() > this.halfCapacity) {
                 // Move the node from mid to tail
                 if (this.queue.remove(node) == null) {
                     // The node may be removed by others through dequeue()