MetaStore Thrift

本文主要是介绍MetaStore Thrift，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

Hive MetaStore整体代码分析
  远程metastore服务端和客户端之间使用Thrift协议通信。IMetaStoreClient接口定义了Metastore的thrift api，该接口中定义了操作元数据的各种方法。Hive中IMetaStoreClient的实现类是HiveMetaStoreClient。

Hive.getMSC() ➔ createMetaStoreClient()
  ↳ RetryingMetaStoreClient.getProxy()//动态代理类创建代理对象
  ↳RetryingMetaStoreClient.RetryingMetaStoreClient()
  ↳MetaStoreUtils.newInstance()//反射实例化对象
  ↳SessionHiveMetaStoreClient.SessionHiveMetaStoreClient()
  ↳HiveMetaStoreClient.HiveMetaStoreClient()
  ↳HiveMetaStoreClient.open()

 1   public HiveMetaStoreClient(HiveConf conf, HiveMetaHookLoader hookLoader)2     throws MetaException {3 4     this.hookLoader = hookLoader;5     if (conf == null) {6       conf = new HiveConf(HiveMetaStoreClient.class);7     }8     this.conf = conf;9     filterHook = loadFilterHooks();
10 　　 //根据hive-site.xml中的hive.metastore.uris配置，如果配置该参数，则认为是远程连接，否则为本地连接
11     String msUri = conf.getVar(HiveConf.ConfVars.METASTOREURIS);
12     localMetaStore = HiveConfUtil.isEmbeddedMetaStore(msUri);
13     if (localMetaStore) {//本地连接直接连接HiveMetaStore
16       client = HiveMetaStore.newRetryingHMSHandler("hive client", conf, true);
17       isConnected = true;
18       snapshotActiveConf();
19       return;
20     }
21 
22     //获取配置中的重试次数及timeout时间
23     retries = HiveConf.getIntVar(conf, HiveConf.ConfVars.METASTORETHRIFTCONNECTIONRETRIES);
24     retryDelaySeconds = conf.getTimeVar(
25         ConfVars.METASTORE_CLIENT_CONNECT_RETRY_DELAY, TimeUnit.SECONDS);
26 
27     //拼接metastore uri
28     if (conf.getVar(HiveConf.ConfVars.METASTOREURIS) != null) {
29       String metastoreUrisString[] = conf.getVar(
30           HiveConf.ConfVars.METASTOREURIS).split(",");
31       metastoreUris = new URI[metastoreUrisString.length];
32       try 

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