Hi,
The idea of accessing Hive metada is to be aware of concurrency. In generall if I do the following In Hive hive> create table test.dummy as select * from oraclehadoop.dummy; We can see that hive applies the locks in Hive [image: Inline images 2] However, there seems to be an issue. *I do not see any exclusive lock on the target table* (i.e. test.dummy). The locking type SHARED_READ on source table oraclehadoop.dummy looks OK One can see the locks in Hive database [image: Inline images 1] So there are few issues here: 1. With Hive -> The source table is locked as SHARED_READ 2. With Spark --> No locks at all 3. With HIVE --> No locks on the target table 4. With Spark --> No locks at all HTH Dr Mich Talebzadeh LinkedIn * https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw <https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw>* http://talebzadehmich.wordpress.com On 8 June 2016 at 20:22, David Newberger <david.newber...@wandcorp.com> wrote: > Could you be looking at 2 jobs trying to use the same file and one getting > to it before the other and finally removing it? > > > > *David Newberger* > > > > *From:* Mich Talebzadeh [mailto:mich.talebza...@gmail.com] > *Sent:* Wednesday, June 8, 2016 1:33 PM > *To:* user; user @spark > *Subject:* Creating a Hive table through Spark and potential locking > issue (a bug) > > > > > > Hi, > > > > I noticed an issue with Spark creating and populating a Hive table. > > > > The process as I see is as follows: > > > > 1. Spark creates the Hive table. In this case an ORC table in a Hive > Database > 2. Spark uses JDBC connection to get data out from an Oracle > 3. I create a temp table in Spark through (registerTempTable) > 4. Spark populates that table. That table is actually created in > > hdfs dfs -ls /tmp/hive/hduser > > drwx------ - hduser supergroup > > /tmp/hive/hduser/b1ea6829-790f-4b37-a0ff-3ed218388059 > > > > > > 1. However, The original table itself does not have any locking on it! > 2. I log in into Hive and drop that table > > 3. hive> drop table dummy; > > OK > > > > 1. That table is dropped OK > 2. Spark crashes with message > > Started at > [08/06/2016 18:37:53.53] > 16/06/08 19:13:46 ERROR Executor: Exception in task 0.0 in stage 1.0 (TID > 1) > > org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.server.namenode.LeaseExpiredException): > No lease on > /user/hive/warehouse/oraclehadoop.db/dummy/.hive-staging_hive_2016-06-08_18-38-08_804_3299712811201460314-1/-ext-10000/_temporary/0/_temporary/attempt_201606081838_0001_m_000000_0/part-00000 > (inode 831621): File does not exist. Holder > DFSClient_NONMAPREDUCE_-1836386597_1 does not have any open files. > at > org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkLease(FSNamesystem.java:3516) > at > org.apache.hadoop.hdfs.server.namenode.FSNamesystem.analyzeFileState(FSNamesystem.java:3313) > at > org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:3169) > at > org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:641) > at > org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:482) > at > org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java) > at > org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:619) > at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:962) > at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2039) > at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2035) > at java.security.AccessController.doPrivileged(Native Method) > at javax.security.auth.Subject.doAs(Subject.java:422) > at > org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1628) > at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2033) > > at org.apache.hadoop.ipc.Client.call(Client.java:1468) > at org.apache.hadoop.ipc.Client.call(Client.java:1399) > at > org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:232) > at com.sun.proxy.$Proxy22.addBlock(Unknown Source) > at > org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.addBlock(ClientNamenodeProtocolTranslatorPB.java:399) > at sun.reflect.GeneratedMethodAccessor16.invoke(Unknown Source) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) > at java.lang.reflect.Method.invoke(Method.java:498) > at > org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:187) > at > org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102) > at com.sun.proxy.$Proxy23.addBlock(Unknown Source) > at > org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.locateFollowingBlock(DFSOutputStream.java:1532) > at > org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1349) > at > org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:588) > 16/06/08 19:13:46 ERROR TaskSetManager: Task 0 in stage 1.0 failed 1 > times; aborting job > > > > Suggested solution. > > In a concurrent env, Spark should apply locks in order to prevent such > operations. Locks are kept in Hive meta data table HIVE_LOCKS > > > > HTH > > Dr Mich Talebzadeh > > > > LinkedIn > *https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw > <https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw>* > > > > http://talebzadehmich.wordpress.com > > >
