MVStore: disabled the file system cache by default (test case)

h2/src/test/org/h2/test/store/TestMVStoreCachePerformance.java

+/*
+ * Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
+ * and the EPL 1.0 (http://h2database.com/html/license.html).
+ * Initial Developer: H2 Group
+ */
+package org.h2.test.store;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.h2.mvstore.MVMap;
+import org.h2.mvstore.MVStore;
+import org.h2.store.fs.FileUtils;
+import org.h2.test.TestBase;
+import org.h2.util.Task;
+
+/**
+ * Tests the MVStore cache.
+ */
+public class TestMVStoreCachePerformance extends TestBase {
+
+    /**
+     * Run just this test.
+     *
+     * @param a ignored
+     */
+    public static void main(String... a) throws Exception {
+        TestBase test = TestBase.createCaller().init();
+        test.test();
+    }
+
+    @Override
+    public void test() throws Exception {
+        testCache(1, "");
+        testCache(1, "cache:");
+        testCache(10, "");
+        testCache(10, "cache:");
+        testCache(100, "");
+        testCache(100, "cache:");
+    }
+
+    private void testCache(int threadCount, String fileNamePrefix) {
+        String fileName = getBaseDir() + "/" + getTestName();
+        fileName = fileNamePrefix  + fileName;
+        FileUtils.delete(fileName);
+        MVStore store = new MVStore.Builder().
+                fileName(fileName).
+                // cacheSize(1024).
+                open();
+        final MVMap<Integer, byte[]> map = store.openMap("test");
+        final AtomicInteger counter = new AtomicInteger();
+        byte[] data = new byte[8 * 1024];
+        final int count = 10000;
+        for (int i = 0; i < count; i++) {
+            map.put(i, data);
+            store.commit();
+            if (i % 1000 == 0) {
+                // System.out.println("add " + i);
+            }
+        }
+        Task[] tasks = new Task[threadCount];
+        for (int i = 0; i < threadCount; i++) {
+            tasks[i] = new Task() {
+
+                @Override
+                public void call() throws Exception {
+                    Random r = new Random();
+                    do {
+                        int id = r.nextInt(count);
+                        map.get(id);
+                        counter.incrementAndGet();
+                    } while (!stop);
+                }
+
+            };
+            tasks[i].execute();
+        }
+        for (int i = 0; i < 4; i++) {
+            // Profiler prof = new Profiler().startCollecting();
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                // ignore
+            }
+            // System.out.println(prof.getTop(5));
+            // System.out.println("  " + counter.get() / (i + 1) + " op/s");
+        }
+        // long time = System.currentTimeMillis();
+        for (Task t : tasks) {
+            t.get();
+        }
+        // System.out.println(System.currentTimeMillis() - time + " ms to stop");
+        store.close();
+        System.out.println(counter.get() / 10000 + " ops/ms; " +
+                threadCount + " thread(s); " + fileNamePrefix);
+    }
+
+}