在本博客的《使用Spark SQL读取Hive上的数据》文章中我介绍了如何通过Spark去读取Hive里面的数据，不过有时候我们在创建SQLContext实例的时候遇到类似下面的异常：

java.lang.RuntimeException: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
	at org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:522)
	at org.apache.spark.sql.hive.client.ClientWrapper.<init>(ClientWrapper.scala:171)
	at org.apache.spark.sql.hive.HiveContext.executionHive$lzycompute(HiveContext.scala:162)
	at org.apache.spark.sql.hive.HiveContext.executionHive(HiveContext.scala:160)
	at org.apache.spark.sql.hive.HiveContext.setConf(HiveContext.scala:391)
	at org.apache.spark.sql.SQLContext$$anonfun$5.apply(SQLContext.scala:235)
	at org.apache.spark.sql.SQLContext$$anonfun$5.apply(SQLContext.scala:234)
	at scala.collection.Iterator$class.foreach(Iterator.scala:727)
	at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
	at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)
	at scala.collection.AbstractIterable.foreach(Iterable.scala:54)
	at org.apache.spark.sql.SQLContext.<init>(SQLContext.scala:234)
	at org.apache.spark.sql.hive.HiveContext.<init>(HiveContext.scala:72)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at org.apache.spark.repl.SparkILoop.createSQLContext(SparkILoop.scala:1028)
	at $iwC$$iwC.<init>(<console>:9)
	at $iwC.<init>(<console>:18)
	at <init>(<console>:20)
	at .<init>(<console>:24)
	at .<clinit>(<console>)
	at .<init>(<console>:7)
	at .<clinit>(<console>)
	at $print(<console>)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:1065)
	at org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1340)
	at org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:840)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:871)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:819)
	at org.apache.spark.repl.SparkILoop.reallyInterpret$1(SparkILoop.scala:857)
	at org.apache.spark.repl.SparkILoop.interpretStartingWith(SparkILoop.scala:902)
	at org.apache.spark.repl.SparkILoop.command(SparkILoop.scala:814)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:132)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:124)
	at org.apache.spark.repl.SparkIMain.beQuietDuring(SparkIMain.scala:324)
	at org.apache.spark.repl.SparkILoopInit$class.initializeSpark(SparkILoopInit.scala:124)
	at org.apache.spark.repl.SparkILoop.initializeSpark(SparkILoop.scala:64)
	at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1$$anonfun$apply$mcZ$sp$5.apply$mcV$sp(SparkILoop.scala:974)
	at org.apache.spark.repl.SparkILoopInit$class.runThunks(SparkILoopInit.scala:159)
	at org.apache.spark.repl.SparkILoop.runThunks(SparkILoop.scala:64)
	at org.apache.spark.repl.SparkILoopInit$class.postInitialization(SparkILoopInit.scala:108)
	at org.apache.spark.repl.SparkILoop.postInitialization(SparkILoop.scala:64)
	at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply$mcZ$sp(SparkILoop.scala:991)
	at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply(SparkILoop.scala:945)
	at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply(SparkILoop.scala:945)
	at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
	at org.apache.spark.repl.SparkILoop.org$apache$spark$repl$SparkILoop$$process(SparkILoop.scala:945)
	at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:1059)
	at org.apache.spark.repl.Main$.main(Main.scala:31)
	at org.apache.spark.repl.Main.main(Main.scala)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:674)
	at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:180)
	at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:205)
	at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:120)
	at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
Caused by: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
	at org.apache.hadoop.hive.metastore.MetaStoreUtils.newInstance(MetaStoreUtils.java:1523)
	at org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.<init>(RetryingMetaStoreClient.java:86)
	at org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.getProxy(RetryingMetaStoreClient.java:132)
	at org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.getProxy(RetryingMetaStoreClient.java:104)
	at org.apache.hadoop.hive.ql.metadata.Hive.createMetaStoreClient(Hive.java:3005)
	at org.apache.hadoop.hive.ql.metadata.Hive.getMSC(Hive.java:3024)
	at org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:503)
	... 64 more
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at org.apache.hadoop.hive.metastore.MetaStoreUtils.newInstance(MetaStoreUtils.java:1521)
	... 70 more
Caused by: MetaException(message:Version information not found in metastore. )
	at org.apache.hadoop.hive.metastore.ObjectStore.checkSchema(ObjectStore.java:6664)
	at org.apache.hadoop.hive.metastore.ObjectStore.verifySchema(ObjectStore.java:6645)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.hadoop.hive.metastore.RawStoreProxy.invoke(RawStoreProxy.java:114)
	at com.sun.proxy.$Proxy14.verifySchema(Unknown Source)
	at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.getMS(HiveMetaStore.java:572)
	at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.createDefaultDB(HiveMetaStore.java:620)
	at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.init(HiveMetaStore.java:461)
	at org.apache.hadoop.hive.metastore.RetryingHMSHandler.<init>(RetryingHMSHandler.java:66)
	at org.apache.hadoop.hive.metastore.RetryingHMSHandler.getProxy(RetryingHMSHandler.java:72)
	at org.apache.hadoop.hive.metastore.HiveMetaStore.newRetryingHMSHandler(HiveMetaStore.java:5762)
	at org.apache.hadoop.hive.metastore.HiveMetaStoreClient.<init>(HiveMetaStoreClient.java:199)
	at org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient.<init>(SessionHiveMetaStoreClient.java:74)
	... 75 more

这是因为在创建SQLContext实例的时候，要求spark编译的Hive版本和HiveMetaStore里面记录的Hive版本一致，我们可以通过配置hive.metastore.schema.verification参数来取消这种验证，这个参数的默认值是true，我们可以取消验证，配置如下：

<property>  
   <name>hive.metastore.schema.verification</name>  
   <value>false</value>  
    <description>  
    Enforce metastore schema version consistency.  
    True: Verify that version information stored in metastore matches with one from Hive jars.  Also disable automatic  
          schema migration attempt. Users are required to manully migrate schema after Hive upgrade which ensures  
          proper metastore schema migration. (Default)  
    False: Warn if the version information stored in metastore doesn't match with one from in Hive jars.  
    </description>  
 </property> 

然后我们再启动Spark，这时候就可以创建SQLContext实例了。