[RocksJava] enable/disable File deletions

java/org/rocksdb/RocksDB.java

@@ -1588,6 +1588,53 @@ public class RocksDB extends RocksObject {
         columnFamilyHandle.nativeHandle_);
   }
 
+  /**
+   * <p>The sequence number of the most recent transaction.</p>
+   *
+   * @return sequence number of the most
+   *     recent transaction.
+   */
+  public long getLatestSequenceNumber() {
+    return getLatestSequenceNumber(nativeHandle_);
+  }
+
+  /**
+   * <p>Prevent file deletions. Compactions will continue to occur,
+   * but no obsolete files will be deleted. Calling this multiple
+   * times have the same effect as calling it once.</p>
+   *
+   * @throws RocksDBException thrown if operation was not performed
+   *     successfully.
+   */
+  public void disableFileDeletions() throws RocksDBException {
+    disableFileDeletions(nativeHandle_);
+  }
+
+  /**
+   * <p>Allow compactions to delete obsolete files.
+   * If force == true, the call to EnableFileDeletions()
+   * will guarantee that file deletions are enabled after
+   * the call, even if DisableFileDeletions() was called
+   * multiple times before.</p>
+   *
+   * <p>If force == false, EnableFileDeletions will only
+   * enable file deletion after it's been called at least
+   * as many times as DisableFileDeletions(), enabling
+   * the two methods to be called by two threads
+   * concurrently without synchronization
+   * -- i.e., file deletions will be enabled only after both
+   * threads call EnableFileDeletions()</p>
+   *
+   * @param force boolean value described above.
+   *
+   * @throws RocksDBException thrown if operation was not performed
+   *     successfully.
+   */
+  public void enableFileDeletions(boolean force)
+      throws RocksDBException {
+    enableFileDeletions(nativeHandle_, force);
+  }
+
   /**
    * <p>Returns an iterator that is positioned at a write-batch containing
    * seq_number. If the sequence number is non existent, it returns an iterator
@@ -1753,6 +1800,11 @@ public class RocksDB extends RocksObject {
   private native void compactRange(long handle, byte[] begin, int beginLen, byte[] end,
       int endLen, boolean reduce_level, int target_level, int target_path_id,
       long cfHandle) throws RocksDBException;
+  private native long getLatestSequenceNumber(long handle);
+  private native void disableFileDeletions(long handle)
+      throws RocksDBException;
+  private native void enableFileDeletions(long handle,
+      boolean force) throws RocksDBException;
   private native long getUpdatesSince(long handle, long sequenceNumber)
       throws RocksDBException;
 

java/org/rocksdb/test/RocksDBTest.java

@@ -738,4 +738,25 @@ public class RocksDBTest {
       }
     }
   }
+
+  @Test
+  public void enableDisableFileDeletions() throws RocksDBException {
+    RocksDB db = null;
+    Options options = null;
+    try {
+      options = new Options().setCreateIfMissing(true);
+      db = RocksDB.open(options, dbFolder.getRoot().getAbsolutePath());
+      db.disableFileDeletions();
+      db.enableFileDeletions(false);
+      db.disableFileDeletions();
+      db.enableFileDeletions(true);
+    } finally {
+      if (db != null) {
+        db.close();
+      }
+      if (options != null) {
+        options.dispose();
+      }
+    }
+  }
 }

java/org/rocksdb/test/TransactionLogIteratorTest.java

@@ -57,6 +57,9 @@ public class TransactionLogIteratorTest {
             String.valueOf(i).getBytes());
       }
       db.flush(new FlushOptions().setWaitForFlush(true));
+
+      assertThat(db.getLatestSequenceNumber()).isEqualTo(250);
+
       transactionLogIterator = db.getUpdatesSince(0);
       assertThat(transactionLogIterator.isValid()).isTrue();
       transactionLogIterator.status();

java/rocksjni/rocksjni.cc

@@ -1601,6 +1601,51 @@ void Java_org_rocksdb_RocksDB_compactRange__J_3BI_3BIZIIJ(
       jend, jend_len, jreduce_level, jtarget_level, jtarget_path_id);
 }
 
+//////////////////////////////////////////////////////////////////////////////
+// rocksdb::DB::GetLatestSequenceNumber
+
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    getLatestSequenceNumber
+ * Signature: (J)V
+ */
+jlong Java_org_rocksdb_RocksDB_getLatestSequenceNumber(JNIEnv* env,
+    jobject jdb, jlong jdb_handle) {
+  auto db = reinterpret_cast<rocksdb::DB*>(jdb_handle);
+  return db->GetLatestSequenceNumber();
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// rocksdb::DB enable/disable file deletions
+
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    enableFileDeletions
+ * Signature: (J)V
+ */
+void Java_org_rocksdb_RocksDB_disableFileDeletions(JNIEnv* env,
+    jobject jdb, jlong jdb_handle) {
+  auto db = reinterpret_cast<rocksdb::DB*>(jdb_handle);
+  rocksdb::Status s = db->DisableFileDeletions();
+  if (!s.ok()) {
+    rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
+  }
+}
+
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    enableFileDeletions
+ * Signature: (JZ)V
+ */
+void Java_org_rocksdb_RocksDB_enableFileDeletions(JNIEnv* env,
+    jobject jdb, jlong jdb_handle, jboolean jforce) {
+  auto db = reinterpret_cast<rocksdb::DB*>(jdb_handle);
+  rocksdb::Status s = db->EnableFileDeletions(jforce);
+  if (!s.ok()) {
+    rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
+  }
+}
+
 //////////////////////////////////////////////////////////////////////////////
 // rocksdb::DB::GetUpdatesSince