hive CliDriver 源码分析

664行 CliDriver main启动

public static void main(String[] args) throws Exception {
int ret = new CliDriver().run(args);
System.exit(ret);
}

646行

public int run(String[] args) throws Exception {

OptionsProcessor oproc = new OptionsProcessor();
if (!oproc.process_stage1(args)) {
return 1;
}

OptionsProcessor oproc = new OptionsProcessor();

OptionsProcessor 初始化  所有options

解析 options  args
if (!oproc.process_stage1(args)) {

在new CliDriver()

  public CliDriver() {
    SessionState ss = SessionState.get();
    conf = (ss != null) ? ss.getConf() : new Configuration();
    Logger LOG = LoggerFactory.getLogger("CliDriver");
    if (LOG.isDebugEnabled()) {
      LOG.debug("CliDriver inited with classpath {}", System.getProperty("java.class.path"));
    }
    console = new LogHelper(LOG);
  }

SessionState.get();
看 SessionState.get

public static SessionState get() {
    return tss.get().state;
  }

tss.是threadlocal  ，threadlocal我想大家都知道，解决多线程共享问题。 threadlocal 包装了一个hashmap 其中key 是this 当前线程。

  private static ThreadLocal<SessionStates> tss = new ThreadLocal<SessionStates>() {
    @Override
    protected SessionStates initialValue() {
      return new SessionStates();
    }
  };

重新 initialValue 当值不存在 new 一个

看看SessionStates

  private static class SessionStates {
    private SessionState state;
    private HiveConf conf;
    private void attach(SessionState state) {
      this.state = state;
      attach(state.getConf());
    }
    private void attach(HiveConf conf) {
      this.conf = conf;

      ClassLoader classLoader = conf.getClassLoader();
      if (classLoader != null) {
        Thread.currentThread().setContextClassLoader(classLoader);
      }
    }
  }

看到

SessionStates 大家明白了

SessionStates 包含两部分

HiveConf 

SessionState 
看看

SessionState 代码

private static final Logger LOG = LoggerFactory.getLogger(SessionState.class);

  private static final String TMP_PREFIX = "_tmp_space.db";
  private static final String LOCAL_SESSION_PATH_KEY = "_hive.local.session.path";
  private static final String HDFS_SESSION_PATH_KEY = "_hive.hdfs.session.path";
  private static final String TMP_TABLE_SPACE_KEY = "_hive.tmp_table_space";
  static final String LOCK_FILE_NAME = "inuse.lck";
  static final String INFO_FILE_NAME = "inuse.info";

  private final Map<String, Map<String, Table>> tempTables = new HashMap<String, Map<String, Table>>();
  private final Map<String, Map<String, ColumnStatisticsObj>> tempTableColStats =
      new HashMap<String, Map<String, ColumnStatisticsObj>>();

  protected ClassLoader parentLoader;

  // Session-scope compile lock.
  private final ReentrantLock compileLock = new ReentrantLock();

  /**
   * current configuration.
   */
  private final HiveConf sessionConf;

  /**
   * silent mode.
   */
  protected boolean isSilent;

  /**
   * verbose mode
   */
  protected boolean isVerbose;

  /**
   * The flag to indicate if the session serves the queries from HiveServer2 or not.
   */
  private boolean isHiveServerQuery = false;

  /**
   * The flag to indicate if the session using thrift jdbc binary serde or not.
   */
  private boolean isUsingThriftJDBCBinarySerDe = false;

  /**
   * The flag to indicate if the session already started so we can skip the init
   */
  private boolean isStarted = false;
  /*
   * HiveHistory Object
   */
  protected HiveHistory hiveHist;

  /**
   * Streams to read/write from.
   */
  public InputStream in;
  public PrintStream out;
  public PrintStream info;
  public PrintStream err;

上面部分代码 可以看出部分命令行的

的值。

可