[RocksJava] - BackupInfos & Restore-/BackupableDB enhancements

Summary:
- BackupableDB deleteBackup method
- BackupableDB purgeOldBackups bugfix
- BackupInfos now available in Restorable-/BackupableDB
- Extended BackupableDBTest to cover more of the currently implemented functionality.

Test Plan:
make rocksdbjava
make jtest

Differential Revision: https://reviews.facebook.net/D27027

java/org/rocksdb/BackupInfo.java

@@ -0,0 +1,67 @@
+// Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+package org.rocksdb;
+
+/**
+ * Instances of this class describe a Backup made by
+ * {@link org.rocksdb.BackupableDB}.
+ */
+public class BackupInfo {
+
+  /**
+   * Package private constructor used to create instances
+   * of BackupInfo by {@link org.rocksdb.BackupableDB} and
+   * {@link org.rocksdb.RestoreBackupableDB}.
+   *
+   * @param backupId id of backup
+   * @param timestamp timestamp of backup
+   * @param size size of backup
+   * @param numberFiles number of files related to this backup.
+   */
+  BackupInfo(int backupId, long timestamp, long size,
+      int numberFiles) {
+    backupId_ = backupId;
+    timestamp_ = timestamp;
+    size_ = size;
+    numberFiles_ = numberFiles;
+  }
+
+  /**
+   *
+   * @return the backup id.
+   */
+  public int backupId() {
+    return backupId_;
+  }
+
+  /**
+   *
+   * @return the timestamp of the backup.
+   */
+  public long timestamp() {
+    return timestamp_;
+  }
+
+  /**
+   *
+   * @return the size of the backup
+   */
+  public long size() {
+    return size_;
+  }
+
+  /**
+   *
+   * @return the number of files of this backup.
+   */
+  public int numberFiles() {
+    return numberFiles_;
+  }
+
+  private int backupId_;
+  private long timestamp_;
+  private long size_;
+  private int numberFiles_;
+}

java/org/rocksdb/BackupableDB.java

@@ -5,6 +5,8 @@
 
 package org.rocksdb;
 
+import java.util.List;
+
 /**
  * A subclass of RocksDB which supports backup-related operations.
  *
@@ -43,8 +45,10 @@ public class BackupableDB extends RocksDB {
    *
    * @param flushBeforeBackup if true, then all data will be flushed
    *     before creating backup.
+   * @throws org.rocksdb.RocksDBException
    */
-  public void createNewBackup(boolean flushBeforeBackup) {
+  public void createNewBackup(boolean flushBeforeBackup)
+      throws RocksDBException {
     createNewBackup(nativeHandle_, flushBeforeBackup);
   }
 
@@ -52,11 +56,32 @@ public class BackupableDB extends RocksDB {
    * Deletes old backups, keeping latest numBackupsToKeep alive.
    *
    * @param numBackupsToKeep Number of latest backups to keep.
+   * @throws org.rocksdb.RocksDBException
    */
-  public void purgeOldBackups(int numBackupsToKeep) {
+  public void purgeOldBackups(int numBackupsToKeep)
+      throws RocksDBException {
     purgeOldBackups(nativeHandle_, numBackupsToKeep);
   }
 
+  /**
+   * Deletes a specific backup.
+   *
+   * @param backupId of backup to delete.
+   * @throws org.rocksdb.RocksDBException
+   */
+  public void deleteBackup(long backupId) throws RocksDBException {
+    deleteBackup0(nativeHandle_, backupId);
+  }
+
+  /**
+   * Returns a list of {@link BackupInfo} instances, which describe
+   * already made backups.
+   *
+   * @return List of {@link BackupInfo} instances.
+   */
+  public List<BackupInfo> getBackupInfos() {
+    return getBackupInfo(nativeHandle_);
+  }
 
   /**
    * Close the BackupableDB instance and release resource.
@@ -85,6 +110,11 @@ public class BackupableDB extends RocksDB {
   }
 
   protected native void open(long rocksDBHandle, long backupDBOptionsHandle);
-  protected native void createNewBackup(long handle, boolean flag);
-  protected native void purgeOldBackups(long handle, int numBackupsToKeep);
+  protected native void createNewBackup(long handle, boolean flag)
+      throws RocksDBException;
+  protected native void purgeOldBackups(long handle, int numBackupsToKeep)
+      throws RocksDBException;
+  private native void deleteBackup0(long nativeHandle, long backupId)
+      throws RocksDBException;
+  protected native List<BackupInfo> getBackupInfo(long handle);
 }

java/org/rocksdb/RestoreBackupableDB.java

@@ -5,6 +5,8 @@
 
 package org.rocksdb;
 
+import java.util.List;
+
 /**
  * This class is used to access information about backups and restore from them.
  *
@@ -65,6 +67,7 @@ public class RestoreBackupableDB extends RocksObject {
    * Deletes old backups, keeping latest numBackupsToKeep alive.
    *
    * @param numBackupsToKeep of latest backups to keep
+   * @throws org.rocksdb.RocksDBException
    */
   public void purgeOldBackups(int numBackupsToKeep) throws RocksDBException {
     purgeOldBackups0(nativeHandle_, numBackupsToKeep);
@@ -74,11 +77,22 @@ public class RestoreBackupableDB extends RocksObject {
    * Deletes a specific backup.
    *
    * @param backupId of backup to delete.
+   * @throws org.rocksdb.RocksDBException
    */
   public void deleteBackup(long backupId) throws RocksDBException {
     deleteBackup0(nativeHandle_, backupId);
   }
 
+  /**
+   * Returns a list of {@link BackupInfo} instances, which describe
+   * already made backups.
+   *
+   * @return List of {@link BackupInfo} instances.
+   */
+  public List<BackupInfo> getBackupInfos() {
+    return getBackupInfo(nativeHandle_);
+  }
+
   /**
    * Release the memory allocated for the current instance
    * in the c++ side.
@@ -90,10 +104,15 @@ public class RestoreBackupableDB extends RocksObject {
 
   private native long newRestoreBackupableDB(long options);
   private native void restoreDBFromBackup0(long nativeHandle, long backupId,
-      String dbDir, String walDir, long restoreOptions) throws RocksDBException;
+      String dbDir, String walDir, long restoreOptions)
+      throws RocksDBException;
   private native void restoreDBFromLatestBackup0(long nativeHandle,
-      String dbDir, String walDir, long restoreOptions) throws RocksDBException;
-  private native void purgeOldBackups0(long nativeHandle, int numBackupsToKeep);
-  private native void deleteBackup0(long nativeHandle, long backupId);
+      String dbDir, String walDir, long restoreOptions)
+      throws RocksDBException;
+  private native void purgeOldBackups0(long nativeHandle, int numBackupsToKeep)
+      throws RocksDBException;
+  private native void deleteBackup0(long nativeHandle, long backupId)
+      throws RocksDBException;
+  protected native List<BackupInfo> getBackupInfo(long handle);
   private native void dispose(long nativeHandle);
 }

java/org/rocksdb/test/BackupableDBTest.java

@@ -7,6 +7,8 @@ package org.rocksdb.test;
 
 import org.rocksdb.*;
 
+import java.util.List;
+
 public class BackupableDBTest {
   static final String db_path = "/tmp/rocksdbjni_backupable_db_test";
   static final String backup_path = "/tmp/rocksdbjni_backupable_db_backup_test";
@@ -21,14 +23,34 @@ public class BackupableDBTest {
     BackupableDBOptions bopt = new BackupableDBOptions(backup_path, false,
         true, false, true, 0, 0);
     BackupableDB bdb = null;
-
+    List<BackupInfo> backupInfos;
+    List<BackupInfo> restoreInfos;
     try {
       bdb = BackupableDB.open(opt, bopt, db_path);
 
       bdb.put("abc".getBytes(), "def".getBytes());
       bdb.put("ghi".getBytes(), "jkl".getBytes());
+
+      backupInfos = bdb.getBackupInfos();
+      assert(backupInfos.size() == 0);
+
       bdb.createNewBackup(true);
 
+      backupInfos = bdb.getBackupInfos();
+      assert(backupInfos.size() == 1);
+
+      // Retrieving backup infos twice shall not
+      // lead to different results
+      List<BackupInfo> tmpBackupInfo = bdb.getBackupInfos();
+      assert(tmpBackupInfo.get(0).backupId() ==
+          backupInfos.get(0).backupId());
+      assert(tmpBackupInfo.get(0).timestamp() ==
+          backupInfos.get(0).timestamp());
+      assert(tmpBackupInfo.get(0).size() ==
+          backupInfos.get(0).size());
+      assert(tmpBackupInfo.get(0).numberFiles() ==
+          backupInfos.get(0).numberFiles());
+
       // delete record after backup
       bdb.remove("abc".getBytes());
       byte[] value = bdb.get("abc".getBytes());
@@ -38,8 +60,26 @@ public class BackupableDBTest {
       // restore from backup
       RestoreOptions ropt = new RestoreOptions(false);
       RestoreBackupableDB rdb = new RestoreBackupableDB(bopt);
+
+      // getting backup infos from restorable db should
+      // lead to the same infos as from backupable db
+      restoreInfos = rdb.getBackupInfos();
+      assert(restoreInfos.size() == backupInfos.size());
+      assert(restoreInfos.get(0).backupId() ==
+          backupInfos.get(0).backupId());
+      assert(restoreInfos.get(0).timestamp() ==
+          backupInfos.get(0).timestamp());
+      assert(restoreInfos.get(0).size() ==
+          backupInfos.get(0).size());
+      assert(restoreInfos.get(0).numberFiles() ==
+          backupInfos.get(0).numberFiles());
+
       rdb.restoreDBFromLatestBackup(db_path, db_path,
           ropt);
+      // do nothing because there is only one backup
+      rdb.purgeOldBackups(1);
+      restoreInfos = rdb.getBackupInfos();
+      assert(restoreInfos.size() == 1);
       rdb.dispose();
       ropt.dispose();
 
@@ -48,6 +88,28 @@ public class BackupableDBTest {
       value = bdb.get("abc".getBytes());
       assert(new String(value).equals("def"));
 
+      bdb.createNewBackup(false);
+      // after new backup there must be two backup infos
+      backupInfos = bdb.getBackupInfos();
+      assert(backupInfos.size() == 2);
+      // deleting the backup must be possible using the
+      // id provided by backup infos
+      bdb.deleteBackup(backupInfos.get(1).backupId());
+      // after deletion there should only be one info
+      backupInfos = bdb.getBackupInfos();
+      assert(backupInfos.size() == 1);
+      bdb.createNewBackup(false);
+      bdb.createNewBackup(false);
+      bdb.createNewBackup(false);
+      backupInfos = bdb.getBackupInfos();
+      assert(backupInfos.size() == 4);
+      // purge everything and keep two
+      bdb.purgeOldBackups(2);
+      // backup infos need to be two
+      backupInfos = bdb.getBackupInfos();
+      assert(backupInfos.size() == 2);
+      assert(backupInfos.get(0).backupId() == 4);
+      assert(backupInfos.get(1).backupId() == 5);
       System.out.println("Backup and restore test passed");
     } catch (RocksDBException e) {
       System.err.format("[ERROR]: %s%n", e);

java/rocksjni/backupablejni.cc

@@ -11,6 +11,7 @@
 #include <stdlib.h>
 #include <jni.h>
 #include <string>
+#include <vector>
 
 #include "include/org_rocksdb_BackupableDB.h"
 #include "include/org_rocksdb_BackupableDBOptions.h"
@@ -53,7 +54,7 @@ void Java_org_rocksdb_BackupableDB_createNewBackup(
  * Signature: (JI)V
  */
 void Java_org_rocksdb_BackupableDB_purgeOldBackups(
-    JNIEnv* env, jobject jbdb, jlong jhandle, jboolean jnumBackupsToKeep) {
+    JNIEnv* env, jobject jbdb, jlong jhandle, jint jnumBackupsToKeep) {
   rocksdb::Status s =
       reinterpret_cast<rocksdb::BackupableDB*>(jhandle)->
       PurgeOldBackups(jnumBackupsToKeep);
@@ -62,6 +63,35 @@ void Java_org_rocksdb_BackupableDB_purgeOldBackups(
   }
 }
 
+/*
+ * Class:     org_rocksdb_BackupableDB
+ * Method:    deleteBackup0
+ * Signature: (JJ)V
+ */
+void Java_org_rocksdb_BackupableDB_deleteBackup0(JNIEnv* env,
+    jobject jobj, jlong jhandle, jlong jbackup_id) {
+  auto rdb = reinterpret_cast<rocksdb::BackupableDB*>(jhandle);
+  rocksdb::Status s = rdb->DeleteBackup(jbackup_id);
+
+  if (!s.ok()) {
+    rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
+  }
+}
+
+/*
+ * Class:     org_rocksdb_BackupableDB
+ * Method:    getBackupInfo
+ * Signature: (J)Ljava/util/List;
+ */
+jobject Java_org_rocksdb_BackupableDB_getBackupInfo(
+    JNIEnv* env, jobject jbdb, jlong jhandle) {
+  std::vector<rocksdb::BackupInfo> backup_infos;
+  reinterpret_cast<rocksdb::BackupableDB*>(jhandle)->
+      GetBackupInfo(&backup_infos);
+  return rocksdb::BackupInfoListJni::getBackupInfo(env,
+      backup_infos);
+}
+
 ///////////////////////////////////////////////////////////////////////////
 // BackupDBOptions
 

java/rocksjni/comparatorjnicallback.cc

@@ -15,7 +15,6 @@ BaseComparatorJniCallback::BaseComparatorJniCallback(
     const ComparatorJniCallbackOptions* copt)
     : mtx_compare(new port::Mutex(copt->use_adaptive_mutex)),
     mtx_findShortestSeparator(new port::Mutex(copt->use_adaptive_mutex)) {
-
   // Note: Comparator methods may be accessed by multiple threads,
   // so we ref the jvm not the env
   const jint rs = env->GetJavaVM(&m_jvm);

java/rocksjni/portal.h

@@ -13,6 +13,7 @@
 #include <jni.h>
 #include <limits>
 #include <string>
+#include <vector>
 
 #include "rocksdb/db.h"
 #include "rocksdb/filter_policy.h"
@@ -591,6 +592,50 @@ class ListJni {
   }
 };
 
+class BackupInfoJni {
+ public:
+  // Get the java class id of org.rocksdb.BackupInfo.
+  static jclass getJClass(JNIEnv* env) {
+    jclass jclazz = env->FindClass("org/rocksdb/BackupInfo");
+    assert(jclazz != nullptr);
+    return jclazz;
+  }
+
+  static jobject construct0(JNIEnv* env, uint32_t backup_id, int64_t timestamp,
+      uint64_t size, uint32_t number_files) {
+    static jmethodID mid = env->GetMethodID(getJClass(env), "<init>",
+        "(IJJI)V");
+    assert(mid != nullptr);
+    return env->NewObject(getJClass(env), mid,
+        backup_id, timestamp, size, number_files);
+  }
+};
+
+class BackupInfoListJni {
+ public:
+  static jobject getBackupInfo(JNIEnv* env,
+      std::vector<BackupInfo> backup_infos) {
+    jclass jclazz = env->FindClass("java/util/ArrayList");
+    jmethodID mid = rocksdb::ListJni::getArrayListConstructorMethodId(
+        env, jclazz);
+    jobject jbackup_info_handle_list = env->NewObject(jclazz, mid,
+        backup_infos.size());
+    // insert in java list
+    for (std::vector<rocksdb::BackupInfo>::size_type i = 0;
+        i != backup_infos.size(); i++) {
+      rocksdb::BackupInfo backup_info = backup_infos[i];
+      jobject obj = rocksdb::BackupInfoJni::construct0(env,
+          backup_info.backup_id,
+          backup_info.timestamp,
+          backup_info.size,
+          backup_info.number_files);
+      env->CallBooleanMethod(jbackup_info_handle_list,
+          rocksdb::ListJni::getListAddMethodId(env), obj);
+    }
+    return jbackup_info_handle_list;
+  }
+};
+
 class JniUtil {
  public:
     /**

java/rocksjni/restorejni.cc

@@ -131,6 +131,20 @@ void Java_org_rocksdb_RestoreBackupableDB_deleteBackup0(JNIEnv* env,
   }
 }
 
+/*
+ * Class:     org_rocksdb_RestoreBackupableDB
+ * Method:    getBackupInfo
+ * Signature: (J)Ljava/util/List;
+ */
+jobject Java_org_rocksdb_RestoreBackupableDB_getBackupInfo(
+    JNIEnv* env, jobject jbdb, jlong jhandle) {
+  std::vector<rocksdb::BackupInfo> backup_infos;
+  reinterpret_cast<rocksdb::RestoreBackupableDB*>(jhandle)->
+      GetBackupInfo(&backup_infos);
+  return rocksdb::BackupInfoListJni::getBackupInfo(env,
+      backup_infos);
+}
+
 /*
  * Class:     org_rocksdb_RestoreBackupableDB
  * Method:    dispose