Add metrics

h2/src/main/org/h2/mvstore/cache/CacheLongKeyLIRS.java

@@ -366,6 +366,32 @@ public class CacheLongKeyLIRS<V> {
         return x;
     }
 
+    /**
+     * Get the number of cache hits.
+     *
+     * @return the cache hits
+     */
+    public long getHits() {
+        long x = 0;
+        for (Segment<V> s : segments) {
+            x += s.hits;
+        }
+        return x;
+    }
+
+    /**
+     * Get the number of cache misses.
+     *
+     * @return the cache misses
+     */
+    public long getMisses() {
+        int x = 0;
+        for (Segment<V> s : segments) {
+            x += s.misses;
+        }
+        return x;
+    }
+
     /**
      * Get the number of resident entries.
      *
@@ -480,6 +506,16 @@ public class CacheLongKeyLIRS<V> {
          */
         int queue2Size;
 
+        /**
+         * The number of cache hits.
+         */
+        long hits;
+
+        /**
+         * The number of cache misses.
+         */
+        long misses;
+
         /**
          * The map array. The size is always a power of 2.
          */
@@ -579,6 +615,8 @@ public class CacheLongKeyLIRS<V> {
          */
         Segment(Segment<V> old, int len) {
             this(old.maxMemory, old.stackMoveDistance, len);
+            hits = old.hits;
+            misses = old.misses;
             Entry<V> s = old.stack.stackPrev;
             while (s != old.stack) {
                 Entry<V> e = copy(s);
@@ -668,11 +706,13 @@ public class CacheLongKeyLIRS<V> {
             Entry<V> e = find(key, hash);
             if (e == null) {
                 // the entry was not found
+                misses++;
                 return null;
             }
             V value = e.value;
             if (value == null) {
                 // it was a non-resident entry
+                misses++;
                 return null;
             }
             if (e.isHot()) {
@@ -685,6 +725,7 @@ public class CacheLongKeyLIRS<V> {
             } else {
                 access(key, hash);
             }
+            hits++;
             return value;
         }