org.apache.hadoop.hive.metastore.StatsSetupConst Maven / Gradle / Ivy

Go to download
/*
 * 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.hive.metastore;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


/**
 * A class that defines the constant strings used by the statistics implementation.
 */
final class StatsSetupConst {

  /**
   * The value of the user variable "hive.stats.dbclass" to use HBase implementation.
   */
  static final String HBASE_IMPL_CLASS_VAL = "hbase";

  /**
   * The value of the user variable "hive.stats.dbclass" to use JDBC implementation.
   */
  static final String JDBC_IMPL_CLASS_VAL = "jdbc";

  /**
   * The name of the statistic Num Files to be published or gathered.
   */
  static final String NUM_FILES = "numFiles";

  /**
   * The name of the statistic Num Partitions to be published or gathered.
   */
  static final String NUM_PARTITIONS = "numPartitions";

  /**
   * The name of the statistic Total Size to be published or gathered.
   * It is hdfs logical size
   */
  static final String TOTAL_SIZE = "totalSize";

  /**
   * The name of the statistic Row Count to be published or gathered.
   */
  static final String ROW_COUNT = "numRows";

  /**
   * The name of the statistic Raw Data Size to be published or gathered.
   * It is size before hive encodes and compresses data.
   */
  static final String RAW_DATA_SIZE = "rawDataSize";

  /**
   * @return List of all supported statistics
   */
  static List getSupportedStats() {
    List supportedStats = new ArrayList();
    supportedStats.addAll(getStatsRequireScan());
    supportedStats.addAll(getStatsNoScan());
    return supportedStats;
  }

  /**
   * @return List of all statistics that need to be collected during query execution. These are
   * statistics that inherently require a scan of the data.
   */
  static List getStatsRequireScan() {
    List collectableStats = new ArrayList();
    collectableStats.add(ROW_COUNT);
    collectableStats.add(RAW_DATA_SIZE);
    return collectableStats;
  }

  /**
   * @return List of statistics that can be collected quickly without requiring a scan of the data.
   */
  static List getStatsNoScan() {
    List fastStats = new ArrayList();
    fastStats.add(NUM_FILES);
    fastStats.add(TOTAL_SIZE);
    return fastStats;
  }

  /**
   * Store all statistics name mapping.
   *
   * One usage is to construct toString for all statistics.
   * @return
   */
  static Map getNameMapping() {
    Map nameMapping = new HashMap();
    nameMapping.put(NUM_FILES, "num_files");
    nameMapping.put(ROW_COUNT, "num_rows");
    nameMapping.put(TOTAL_SIZE, "total_size");
    nameMapping.put(RAW_DATA_SIZE, "raw_data_size");
    return nameMapping;
  }
}