hive metastore 初始化

hive metastore的初始化init函数信息量非常丰富, 顺着把所有关联的调用函数看下去, 大概就能理解metastore的工作流程了.

package org.apache.hadoop.hive.metastore;


public class HiveMetaStore extends ThriftHiveMetastore {


    private ClassLoader classLoader;
    private AlterHandler alterHandler;
    private List<MetaStorePreEventListener> preListeners;
    private List<MetaStoreEventListener> listeners;
    private List<MetaStoreEventListener> transactionalListeners;
    private List<MetaStoreEndFunctionListener> endFunctionListeners;
    private List<MetaStoreInitListener> initListeners;
    private Pattern partitionValidationPattern;
    private final boolean isInTest;

    @Override
    public void init() throws MetaException {
      initListeners = MetaStoreUtils.getMetaStoreListeners(
          MetaStoreInitListener.class, hiveConf,
          hiveConf.getVar(HiveConf.ConfVars.METASTORE_INIT_HOOKS));
      for (MetaStoreInitListener singleInitListener: initListeners) {
          MetaStoreInitContext context = new MetaStoreInitContext();
          singleInitListener.onInit(context);
      }

      String alterHandlerName = hiveConf.get("hive.metastore.alter.impl",
          HiveAlterHandler.class.getName());
      alterHandler = (AlterHandler) ReflectionUtils.newInstance(MetaStoreUtils.getClass(
          alterHandlerName), hiveConf);
      wh = new Warehouse(hiveConf);

      synchronized (HMSHandler.class) {
        if (currentUrl == null || !currentUrl.equals(MetaStoreInit.getConnectionURL(hiveConf))) {
          createDefaultDB();
          createDefaultRoles();
          addAdminUsers();
          currentUrl = MetaStoreInit.getConnectionURL(hiveConf);
        }
      }

      //Start Metrics for Embedded mode
      if (hiveConf.getBoolVar(ConfVars.METASTORE_METRICS)) {
        try {
          MetricsFactory.init(hiveConf);
        } catch (Exception e) {
          // log exception, but ignore inability to start
          LOG.error("error in Metrics init: " + e.getClass().getName() + " "
              + e.getMessage(), e);
        }
      }

      Metrics metrics = MetricsFactory.getInstance();
      if (metrics != null && hiveConf.getBoolVar(ConfVars.METASTORE_INIT_METADATA_COUNT_ENABLED)) {
        LOG.info("Begin calculating metadata count metrics.");
        updateMetrics();
        LOG.info("Finished metadata count metrics: " + initDatabaseCount + " databases, " + initTableCount +
          " tables, " + initPartCount + " partitions.");
        metrics.addGauge(MetricsConstant.INIT_TOTAL_DATABASES, new MetricsVariable() {
          @Override
          public Object getValue() {
            return initDatabaseCount;
          }
        });
        metrics.addGauge(MetricsConstant.INIT_TOTAL_TABLES, new MetricsVariable() {
          @Override
          public Object getValue() {
            return initTableCount;
          }
        });
        metrics.addGauge(MetricsConstant.INIT_TOTAL_PARTITIONS, new MetricsVariable() {
          @Override
          public Object getValue() {
            return initPartCount;
          }
        });
      }

      preListeners = MetaStoreUtils.getMetaStoreListeners(MetaStorePreEventListener.class,
          hiveConf,
          hiveConf.getVar(HiveConf.ConfVars.METASTORE_PRE_EVENT_LISTENERS));
      preListeners.add(0, new TransactionalValidationListener(hiveConf));
      listeners = MetaStoreUtils.getMetaStoreListeners(MetaStoreEventListener.class, hiveConf,
          hiveConf.getVar(HiveConf.ConfVars.METASTORE_EVENT_LISTENERS));
      listeners.add(new SessionPropertiesListener(hiveConf));
      listeners.add(new AcidEventListener(hiveConf));
      transactionalListeners = MetaStoreUtils.getMetaStoreListeners(MetaStoreEventListener.class,hiveConf,
              hiveConf.getVar(ConfVars.METASTORE_TRANSACTIONAL_EVENT_LISTENERS));
      if (metrics != null) {
        listeners.add(new HMSMetricsListener(hiveConf, metrics));
      }

      endFunctionListeners = MetaStoreUtils.getMetaStoreListeners(
          MetaStoreEndFunctionListener.class, hiveConf,
          hiveConf.getVar(HiveConf.ConfVars.METASTORE_END_FUNCTION_LISTENERS));

      String partitionValidationRegex =
          hiveConf.getVar(HiveConf.ConfVars.METASTORE_PARTITION_NAME_WHITELIST_PATTERN);
      if (partitionValidationRegex != null && !partitionValidationRegex.isEmpty()) {
        partitionValidationPattern = Pattern.compile(partitionValidationRegex);
      } else {
        partitionValidationPattern = null;
      }

      long cleanFreq = hiveConf.getTimeVar(ConfVars.METASTORE_EVENT_CLEAN_FREQ, TimeUnit.MILLISECONDS);
      if (cleanFreq > 0) {
        // In default config, there is no timer.
        Timer cleaner = new Timer("Metastore Events Cleaner Thread", true);
        cleaner.schedule(new EventCleanerTask(this), cleanFreq, cleanFreq);
      }

      expressionProxy = PartFilterExprUtil.createExpressionProxy(hiveConf);
      fileMetadataManager = new FileMetadataManager((ThreadLocalRawStore)this, hiveConf);
    }

}