code: /*
   * 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.skywalking.oap.server.storage.plugin.jdbc.common.dao;
  
  import lombok.RequiredArgsConstructor;
  import lombok.SneakyThrows;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.skywalking.oap.server.core.analysis.DownSampling;
  import org.apache.skywalking.oap.server.core.analysis.TimeBucket;
  import org.apache.skywalking.oap.server.core.storage.IHistoryDeleteDAO;
  import org.apache.skywalking.oap.server.core.storage.model.Model;
  import org.apache.skywalking.oap.server.library.client.jdbc.hikaricp.JDBCClient;
  import org.apache.skywalking.oap.server.storage.plugin.jdbc.SQLBuilder;
  import org.apache.skywalking.oap.server.storage.plugin.jdbc.common.JDBCTableInstaller;
  import org.apache.skywalking.oap.server.storage.plugin.jdbc.common.TableHelper;
  import org.joda.time.DateTime;
  
  import java.time.Clock;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.TimeUnit;
  
  @Slf4j
  @RequiredArgsConstructor
  public class JDBCHistoryDeleteDAO implements IHistoryDeleteDAO {
      private final JDBCClient jdbcClient;
      private final TableHelper tableHelper;
      private final JDBCTableInstaller modelInstaller;
      private final Clock clock;
  
      private final Map<String, Long> lastDeletedTimeBucket = new ConcurrentHashMap<>();
  
      @Override
      @SneakyThrows
      public void deleteHistory(Model model, String timeBucketColumnName, int ttl) {
          final var endTimeBucket = TimeBucket.getTimeBucket(clock.millis() + TimeUnit.DAYS.toMillis(1), DownSampling.Day);
          final var startTimeBucket = TimeBucket.getTimeBucket(clock.millis() - TimeUnit.DAYS.toMillis(ttl), DownSampling.Day);
          log.info(
              "Deleting history data, ttl: {}, now: {}. Keep [{}, {}]",
              ttl,
              clock.millis(),
              startTimeBucket,
              endTimeBucket
          );
  
          final var deadline = Long.parseLong(new DateTime().minusDays(ttl).toString("yyyyMMdd"));
          final var lastSuccessDeadline = lastDeletedTimeBucket.getOrDefault(model.getName(), 0L);
          if (deadline <= lastSuccessDeadline) {
              if (log.isDebugEnabled()) {
                  log.debug(
                      "The deadline {} is less than the last success deadline {}, skip deleting history data",
                      deadline,
                      lastSuccessDeadline
                  );
              }
              return;
          }
  
          final var ttlTables = tableHelper.getTablesInTimeBucketRange(model.getName(), startTimeBucket, endTimeBucket);
          final var tablesToDrop = new HashSet<String>();
          final var tableName = TableHelper.getTableName(model);
  
          try (final var conn = jdbcClient.getConnection();
               final var result = conn.getMetaData().getTables(null, null, tableName + "%", new String[]{"TABLE"})) {
              while (result.next()) {
                  tablesToDrop.add(result.getString("TABLE_NAME"));
              }
          }
  
          ttlTables.forEach(tablesToDrop::remove);
          tablesToDrop.removeIf(it -> !it.matches(tableName + "_\\d{8}$"));
          for (final var table : tablesToDrop) {
              final var dropSql = new SQLBuilder("drop table if exists ").append(table);
              jdbcClient.executeUpdate(dropSql.toString());
          }
  
          // Drop additional tables
          for (final var table : tablesToDrop) {
              final var timeBucket = TableHelper.getTimeBucket(table);
              for (final var additionalTable : model.getSqlDBModelExtension().getAdditionalTables().values()) {
                  final var additionalTableToDrop = TableHelper.getTable(additionalTable.getName(), timeBucket);
                  final var dropSql = new SQLBuilder("drop table if exists ").append(additionalTableToDrop);
                  jdbcClient.executeUpdate(dropSql.toString());
              }
          }
  
          // Create tables for the next day.
          final var nextTimeBucket = TimeBucket.getTimeBucket(clock.millis() + TimeUnit.DAYS.toMillis(1), DownSampling.Day);
          modelInstaller.createTable(model, nextTimeBucket);
  
          lastDeletedTimeBucket.put(model.getName(), deadline);
      }
  }
  