This seems related: HBASE-14128
FYI On Thu, Jan 7, 2016 at 9:24 AM, Deepti Bhogle <dbho...@connexity.com> wrote: > We currently do exactly that. We create multiple instances of > TableSnapshotScanner each with a unique dir location against the same > snapshot. But doing so gives us the exception mentioned. Does that mean we > can’t run multiple instances at the same time? > Deepti Bhogle | Senior Software Engineer | Connexity, Inc. > Phone: 858.652.4318 | dbho...@connexity.com > > > > > > > > On 1/7/16, 3:46 AM, "Enis Söztutar" <e...@apache.org> wrote: > > >TableSnapshotScanner itself does not support more than one scanner. Are > you > >creating more than 1 TableSnapshotScanner in your parallel scan? > > > >Everytime a snapshot scanner is initiated, it will try to "restore" the > >snapshot to a temporary location out of the regular root directory in > hdfs. > >You can try to give different restore directories to each > >TableSnapshotScanner. > > > >Enis > > > >On Wed, Jan 6, 2016 at 5:51 PM, dbhogle <dbho...@connexity.com> wrote: > > > >> Using the client api, we can scan the snapshot using a single scanner. > We > >> currently create an instance of TableSnapshotScanner providing it with a > >> unique dir location per scanner. We are currently on cdh 5.4.5 and using > >> the > >> hbase 1.0.0-cdh5.4.5 api. In order to get desired throughput, we tried > to > >> increase the number of parallel scanners but raising the no. of scanner > >> instances throws the following exception, the occurrence increases as > the > >> no. of scanners goes up. > >> Can the client api support multiple scanners for a single snapshot? > >> > >> java.io.IOException: java.util.concurrent.ExecutionException: > >> > >> > org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException): > >> failed to create file > >> > >> > /hbase/archive/data/default/<tableName>/cb794cfb7948ba8b1f4e73b690dfbfe5/L/.links-a04e1a5b2141445eb1b9e2429f1eced2/cb794cfb7948ba8b1f4e73b690dfbfe5.<tableName> > >> for DFSClient_NONMAPREDUCE_672650916_1 for client 10.10.2.90 because > >> current > >> leaseholder is trying to recreate file. > >> at > >> > >> > org.apache.hadoop.hdfs.server.namenode.FSNamesystem.recoverLeaseInternal(FSNamesystem.java:3077) > >> at > >> > >> > org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInternal(FSNamesystem.java:2783) > >> at > >> > >> > org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInt(FSNamesystem.java:2676) > >> at > >> > >> > org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:2560) > >> at > >> > >> > org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.create(NameNodeRpcServer.java:585) > >> at > >> > >> > org.apache.hadoop.hdfs.server.namenode.AuthorizationProviderProxyClientProtocol.create(AuthorizationProviderProxyClientProtocol.java:110) > >> at > >> > >> > org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.create(ClientNamenodeProtocolServerSideTranslatorPB.java:395) > >> 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:1060) > >> at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2044) > >> at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2040) > >> at java.security.AccessController.doPrivileged(Native Method) > >> at javax.security.auth.Subject.doAs(Subject.java:415) > >> at > >> > >> > org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1671) > >> at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2038) > >> > >> at > >> > >> > org.apache.hadoop.hbase.util.ModifyRegionUtils.createRegions(ModifyRegionUtils.java:162) > >> at > >> > >> > org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper.cloneHdfsRegions(RestoreSnapshotHelper.java:561) > >> at > >> > >> > org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper.restoreHdfsRegions(RestoreSnapshotHelper.java:237) > >> at > >> > >> > org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper.restoreHdfsRegions(RestoreSnapshotHelper.java:159) > >> at > >> > >> > org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper.copySnapshotForScanner(RestoreSnapshotHelper.java:812) > >> at > >> > >> > org.apache.hadoop.hbase.client.TableSnapshotScanner.init(TableSnapshotScanner.java:156) > >> at > >> > >> > org.apache.hadoop.hbase.client.TableSnapshotScanner.<init>(TableSnapshotScanner.java:124) > >> at > >> > >> > org.apache.hadoop.hbase.client.TableSnapshotScanner.<init>(TableSnapshotScanner.java:101) > >> at > >> net.connexity.aro.data.AudienceScanner.join(AudienceScanner.scala:68) > >> at > >> net.connexity.aro.actor.ScanActor.joinAudience(ScanActor.scala:190) > >> at > >> > >> > net.connexity.aro.actor.ScanActor$$anonfun$receive$1.applyOrElse(ScanActor.scala:90) > >> at akka.actor.Actor$class.aroundReceive(Actor.scala:467) > >> at > >> net.connexity.aro.actor.ScanActor.aroundReceive(ScanActor.scala:36) > >> at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516) > >> at akka.actor.ActorCell.invoke(ActorCell.scala:487) > >> at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238) > >> at akka.dispatch.Mailbox.run(Mailbox.scala:220) > >> at > >> > >> > akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:397) > >> at > >> scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) > >> at > >> > >> > scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) > >> at > >> scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) > >> at > >> > >> > scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) > >> > >> > >> > >> -- > >> View this message in context: > >> > http://apache-hbase.679495.n3.nabble.com/Parallel-scanning-of-snapshots-using-hbase-client-api-tp4077014.html > >> Sent from the HBase Developer mailing list archive at Nabble.com. > >> >