support getUsage and getPinnedUsage in JavaAPI for Cache (#7925)

Summary:
support getUsage and getPinnedUsage in JavaAPI for Cache
also fix a typo in LRUCacheTest.java that the highPriPoolRatio is not valid(set 5, I guess it means 0.05)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7925

Reviewed By: mrambacher

Differential Revision: D26900241

Pulled By: ajkr

fbshipit-source-id: 735d1e40a16fa8919c89c7c7154ba7f81208ec33

java/CMakeLists.txt

@@ -13,6 +13,7 @@ set(JNI_NATIVE_SOURCES
         rocksjni/cassandra_value_operator.cc
         rocksjni/checkpoint.cc
         rocksjni/clock_cache.cc
+        rocksjni/cache.cc
         rocksjni/columnfamilyhandle.cc
         rocksjni/compaction_filter.cc
         rocksjni/compaction_filter_factory.cc
@@ -426,6 +427,7 @@ if(${CMAKE_VERSION} VERSION_LESS "3.11.4" OR (${Java_VERSION_MINOR} STREQUAL "7"
           org.rocksdb.CassandraValueMergeOperator
           org.rocksdb.Checkpoint
           org.rocksdb.ClockCache
+          org.rocksdb.Cache
           org.rocksdb.ColumnFamilyHandle
           org.rocksdb.ColumnFamilyOptions
           org.rocksdb.CompactionJobInfo

java/Makefile

@@ -14,6 +14,7 @@ NATIVE_JAVA_CLASSES = \
 	org.rocksdb.BloomFilter\
 	org.rocksdb.Checkpoint\
 	org.rocksdb.ClockCache\
+	org.rocksdb.Cache\
 	org.rocksdb.CassandraCompactionFilter\
 	org.rocksdb.CassandraValueMergeOperator\
 	org.rocksdb.ColumnFamilyHandle\

java/rocksjni/cache.cc

@@ -0,0 +1,35 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// This file implements the "bridge" between Java and C++ for
+// ROCKSDB_NAMESPACE::Cache.
+
+#include "rocksdb/cache.h"
+
+#include <jni.h>
+
+#include "include/org_rocksdb_Cache.h"
+
+/*
+ * Class:     org_rocksdb_Cache
+ * Method:    getUsage
+ * Signature: (J)J
+ */
+jlong Java_org_rocksdb_Cache_getUsage(JNIEnv*, jclass, jlong jhandle) {
+  auto* sptr_cache =
+      reinterpret_cast<std::shared_ptr<ROCKSDB_NAMESPACE::Cache>*>(jhandle);
+  return static_cast<jlong>(sptr_cache->get()->GetUsage());
+}
+
+/*
+ * Class:     org_rocksdb_Cache
+ * Method:    getPinnedUsage
+ * Signature: (J)J
+ */
+jlong Java_org_rocksdb_Cache_getPinnedUsage(JNIEnv*, jclass, jlong jhandle) {
+  auto* sptr_cache =
+      reinterpret_cast<std::shared_ptr<ROCKSDB_NAMESPACE::Cache>*>(jhandle);
+  return static_cast<jlong>(sptr_cache->get()->GetPinnedUsage());
+}

java/src/main/java/org/rocksdb/Cache.java

@@ -10,4 +10,31 @@ public abstract class Cache extends RocksObject {
   protected Cache(final long nativeHandle) {
     super(nativeHandle);
   }
+
+  /**
+   * Returns the memory size for the entries
+   * residing in cache.
+   *
+   * @return cache usage size.
+   *
+   */
+  public long getUsage() {
+    assert (isOwningHandle());
+    return getUsage(this.nativeHandle_);
+  }
+
+  /**
+   * Returns the memory size for the entries
+   * being pinned in cache.
+   *
+   * @return cache pinned usage size.
+   *
+   */
+  public long getPinnedUsage() {
+    assert (isOwningHandle());
+    return getPinnedUsage(this.nativeHandle_);
+  }
+
+  private native static long getUsage(final long handle);
+  private native static long getPinnedUsage(final long handle);
 }

java/src/test/java/org/rocksdb/LRUCacheTest.java

@@ -5,23 +5,27 @@
 
 package org.rocksdb;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.ClassRule;
 import org.junit.Test;
 
 public class LRUCacheTest {
-
+  @ClassRule
-  static {
+  public static final RocksNativeLibraryResource ROCKS_NATIVE_LIBRARY_RESOURCE =
-    RocksDB.loadLibrary();
+      new RocksNativeLibraryResource();
-  }
 
   @Test
   public void newLRUCache() {
-    final long capacity = 1000;
+    final long capacity = 80000000;
     final int numShardBits = 16;
     final boolean strictCapacityLimit = true;
-    final double highPriPoolRatio = 5;
+    final double highPriPoolRatio = 0.05;
     try(final Cache lruCache = new LRUCache(capacity,
         numShardBits, strictCapacityLimit, highPriPoolRatio)) {
       //no op
+      assertThat(lruCache.getUsage()).isGreaterThanOrEqualTo(0);
+      assertThat(lruCache.getPinnedUsage()).isGreaterThanOrEqualTo(0);
     }
   }
 }

src.mk

@@ -562,6 +562,7 @@ JNI_NATIVE_SOURCES =                                          \
   java/rocksjni/backupablejni.cc                              \
   java/rocksjni/checkpoint.cc                                 \
   java/rocksjni/clock_cache.cc                                \
+  java/rocksjni/cache.cc                                      \
   java/rocksjni/columnfamilyhandle.cc                         \
   java/rocksjni/compact_range_options.cc                      \
   java/rocksjni/compaction_filter.cc                          \