Question

我正在尝试为我的应用程序清理Cassandra连接资源，并且我的应用程序会在一段时间后挂起。我一直在下面得到这个例外。我不知道如何解决这个问题。我的堆栈跟踪在下面。

Cassandra资源清理的最佳做法是什么？该应用程序部署在Tomcat服务器上。

SEVERE: RuntimeException while executing runnable com.google.common.util.concurrent.Futures$ChainingListenableFuture@7c435ce7 with executor com.google.common.util.concurrent.MoreExecutors$ListeningDecorator@6358d4ec
java.util.concurrent.RejectedExecutionException: Task com.google.common.util.concurrent.Futures$ChainingListenableFuture@7c435ce7 rejected from java.util.concurrent.ThreadPoolExecutor@96203d77[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 2]
at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2059)
at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1383)
at com.google.common.util.concurrent.MoreExecutors$ListeningDecorator.execute(MoreExecutors.java:484)
at com.google.common.util.concurrent.ExecutionList.executeListener(ExecutionList.java:156)
at com.google.common.util.concurrent.ExecutionList.add(ExecutionList.java:101)
at com.google.common.util.concurrent.AbstractFuture.addListener(AbstractFuture.java:170)
at com.google.common.util.concurrent.Futures.transform(Futures.java:608)
at com.google.common.util.concurrent.Futures.transform(Futures.java:717)
at com.datastax.driver.core.SessionManager.toPreparedStatement(SessionManager.java:185)
at com.datastax.driver.core.SessionManager.prepareAsync(SessionManager.java:126)
at com.datastax.driver.core.SessionManager.prepare(SessionManager.java:109)
at com.bofa.ecom.search.dao.ConfigPropertyDao.readProperties(ConfigPropertyDao.java:87)

我的代码

public class CassandraDao implements Dao, AutoCloseable {

  private final Session session;

  private final Cluster cluster;

  private final String keyspace;

  private final String host;


  /**
   * Initializes and validates the session for a given keyspace.
   * 
   * <p>
   * It is the responsibility of the invoking function to close the session and
   * any other resources associated with the database.
   * 
   * @param host host
   * @param keyspace keyspace to connect to and validate
   * @throws UnavailableHostException if the host can not be reached
   */
  public ConfigPropertyDao(String host, String keyspace) throws DatabaseException {
    this.host = Objects.requireNonNull(host, "Cassandra host can not be null.");
    this.keyspace = Objects.requireNonNull(keyspace, "Cassandra keyspace can not be null.");
    LOGGER.debug(
        String.format("Initializing the cluster and session for host :%s and keyspace:%s",
            host, keyspace));
    if (this.cluster == null) {
      this.cluster = Cluster.builder().addContactPoint(Objects.requireNonNull(this.host)).build();
    }
    this.session = cluster.connect(this.keyspace);
    if (LOGGER.isDebugEnabled()) {
      LOGGER.debug(
          String.format(
              "The session has been initialized for host: %s and keyspace %s", host, keyspace));
    }
  }
}

@Override
public void close() throws Exception {
  //**UPDATE**: Check if not closed. Bad Copy paste on my part.
  if (!this.session.isClosed()) {
    this.session.close(); 
  }

  if (!this.cluster.isClosed()) {
    this.cluter.close();
  }
}

如何在没有内存泄漏的情况下清理Cassandra资源？

0 个答案: