added "test case"

h2/src/test/org/h2/test/db/TestLIRSMemoryConsumption.java

+package org.h2.test.db;
+
+import org.h2.mvstore.cache.CacheLongKeyLIRS;
+import org.h2.test.TestBase;
+import org.h2.test.TestDb;
+import java.util.Random;
+
+/**
+ * Class TestLIRSMemoryConsumption.
+ * <UL>
+ * <LI> 8/5/18 10:57 PM initial creation
+ * </UL>
+ *
+ * @author <a href='mailto:andrei.tokar@gmail.com'>Andrei Tokar</a>
+ */
+public class TestLIRSMemoryConsumption extends TestDb {
+
+    /**
+     * Run just this test.
+     *
+     * @param a
+     *              ignored
+     */
+    public static void main(String... a) throws Exception {
+        TestBase.createCaller().init().test();
+    }
+
+    @Override
+    public void test() {
+        testMemoryConsumption();
+        System.out.println("-----------------------");
+        testMemoryConsumption();
+        System.out.println("-----------------------");
+        testMemoryConsumption();
+    }
+
+    private void testMemoryConsumption() {
+        int size = 1_000_000;
+        Random rng = new Random();
+        CacheLongKeyLIRS.Config config = new CacheLongKeyLIRS.Config();
+        for (int mb = 1; mb <= 16; mb *= 2) {
+            config.maxMemory = mb * 1024 * 1024;
+            CacheLongKeyLIRS<Object> cache = new CacheLongKeyLIRS<>(config);
+            long memoryUsedInitial = getMemUsedKb();
+            for (int i = 0; i < size; i++) {
+                cache.put(i, createValue(i), getValueSize(i));
+            }
+            for (int i = 0; i < size; i++) {
+                int key;
+                int mode = rng.nextInt(4);
+                switch(mode) {
+                    default:
+                    case 0:
+                        key = rng.nextInt(10);
+                        break;
+                    case 1:
+                        key = rng.nextInt(100);
+                        break;
+                    case 2:
+                        key = rng.nextInt(10_000);
+                        break;
+                    case 3:
+                        key = rng.nextInt(1_000_000);
+                        break;
+                }
+                Object val = cache.get(key);
+                if (val == null) {
+                    cache.put(key, createValue(key), getValueSize(key));
+                }
+            }
+
+            eatMemory(1);
+            freeMemory();
+            cache.trimNonResidentQueue();
+            long memoryUsed = getMemUsedKb();
+
+            int sizeHot = cache.sizeHot();
+            int sizeResident = cache.size();
+            int sizeNonResident = cache.sizeNonResident();
+            long hits = cache.getHits();
+            long misses = cache.getMisses();
+            System.out.println(mb + " | " +
+                    (memoryUsed - memoryUsedInitial + 512) / 1024 + " | " +
+                    (sizeResident+sizeNonResident) + " | " +
+                    sizeHot + " | " + (sizeResident - sizeHot) + " | " + sizeNonResident +
+                    " | " + (hits * 100 / (hits + misses)) );
+        }
+    }
+
+    private Object createValue(long key) {
+//        return new Object();
+        return new byte[2540];
+    }
+
+    private int getValueSize(long key) {
+//        return 16;
+        return 2560;
+    }
+
+    private long getMemUsedKb() {
+        Runtime rt = Runtime.getRuntime();
+        long memory = Long.MAX_VALUE;
+        for (int i = 0; i < 8; i++) {
+            rt.gc();
+            long memNow = (rt.totalMemory() - rt.freeMemory()) / 1024;
+            if (memNow >= memory) {
+                break;
+            }
+            memory = memNow;
+            try { Thread.sleep(1000); } catch (InterruptedException e) {/**/}
+        }
+        return memory;
+    }
+}