hadoop-ozone/tools/src/main/java/org/apache/hadoop/ozone/debug/DropTable.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.hadoop.ozone.debug;

import org.apache.hadoop.hdds.cli.SubcommandWithParent;
import org.rocksdb.ColumnFamilyDescriptor;
import org.rocksdb.ColumnFamilyHandle;
import org.rocksdb.RocksDB;
import picocli.CommandLine;

import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Callable;

/**
 * Drop a column Family/Table in db.
 */
@CommandLine.Command(
        name = "drop_column_family",
        description = "drop column family in db."
)
public class DropTable implements Callable<Void>, SubcommandWithParent {

  @CommandLine.Option(names = {"--column_family"},
      description = "Table name")
  private String tableName;

  @CommandLine.ParentCommand
  private RDBParser parent;

  @Override
  public Void call() throws Exception {
    List<ColumnFamilyDescriptor> cfs =
        RocksDBUtils.getColumnFamilyDescriptors(parent.getDbPath());
    final List<ColumnFamilyHandle> columnFamilyHandleList =
        new ArrayList<>();
    try (RocksDB rocksDB = RocksDB.open(
        parent.getDbPath(), cfs, columnFamilyHandleList)) {
      byte[] nameBytes = tableName.getBytes(StandardCharsets.UTF_8);
      ColumnFamilyHandle toBeDeletedCf = null;
      for (ColumnFamilyHandle cf : columnFamilyHandleList) {
        if (Arrays.equals(cf.getName(), nameBytes)) {
          toBeDeletedCf = cf;
          break;
        }
      }
      if (toBeDeletedCf == null) {
        System.err.println(tableName + " is not in a column family in DB "
            + parent.getDbPath());
      } else {
        System.out.println(tableName + " will be deleted from DB "
            + parent.getDbPath());
        rocksDB.dropColumnFamily(toBeDeletedCf);
      }
    }
    return null;
  }

  @Override
  public Class<?> getParentType() {
    return RDBParser.class;
  }
}