Just had something odd happen - my keyspace disappeared. I'm curious if anyone has seen the same or may have an explanation.
I am using Titan 0.2.0 and Cassandra 1.1.6. I ran my application which creates a graph and progressively builds it for a couple of hours. But before completing, Cassandra seems to simply lose track of the keyspace, "Recommender". The exception is that it doesn't exist. So I check in cassandra-cli, and it also doesn't show the keyspace. The data directory and column family directories are there, but are empty. Restarting cassandra doesn't change anything. Ron Here is part of my application log and the Cassandra log from the relevant time: 2013-02-07 17:58:02,012 [pool-10-thread-26] INFO publisher.GraphPublisher - RelationProcessor started fo r items [47070, 34334, 34334, 34334, 42297, 34334, 34334] 2013-02-07 17:58:02,550 [pool-10-thread-36] ERROR publisher.GraphPublisher - Unhandled error for account 7314766 order 17489735 com.thinkaurelius.titan.core.TitanException: Could not read from storage after 3 attempts at com.thinkaurelius.titan.graphdb.database.StandardTitanGraph.readException(StandardTitanGraph.j ava:162) at com.thinkaurelius.titan.graphdb.database.StandardTitanGraph.appendResults(StandardTitanGraph.j ava:607) at com.thinkaurelius.titan.graphdb.database.StandardTitanGraph.appendResults(StandardTitanGraph.j ava:592) at com.thinkaurelius.titan.graphdb.database.StandardTitanGraph.queryForEntries(StandardTitanGraph .java:557) at com.thinkaurelius.titan.graphdb.database.StandardTitanGraph.loadRelations(StandardTitanGraph.j ava:322) at com.thinkaurelius.titan.graphdb.transaction.StandardPersistTitanTx.loadRelations(StandardPersi stTitanTx.java:155) at com.thinkaurelius.titan.graphdb.vertices.AbstractTitanVertex.ensureLoadedEdges(AbstractTitanVe rtex.java:88) at com.thinkaurelius.titan.graphdb.vertices.StandardTitanVertex.getRelations(StandardTitanVertex. java:68) at com.thinkaurelius.titan.graphdb.query.SimpleAtomicQuery.propertyIterator(SimpleAtomicQuery.jav a:461) at com.thinkaurelius.titan.graphdb.vertices.AbstractTitanVertex.getProperty(AbstractTitanVertex.j ava:115) at com.thinkaurelius.titan.graphdb.vertices.AbstractTitanVertex.getProperty(AbstractTitanVertex.j ava:127) at com.charityusa.publisher.GraphPublisher.updateRelation(GraphPublisher.java:206) at com.charityusa.publisher.GraphPublisher.access$100(GraphPublisher.java:55) at com.charityusa.publisher.GraphPublisher$OrderProcessor.call(GraphPublisher.java:320) at com.charityusa.publisher.GraphPublisher$OrderProcessor.call(GraphPublisher.java:266) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) at java.util.concurrent.FutureTask.run(FutureTask.java:166) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:722) Caused by: com.thinkaurelius.titan.diskstorage.TemporaryStorageException: Temporary failure in storage ba ckend at com.thinkaurelius.titan.diskstorage.cassandra.astyanax.AstyanaxOrderedKeyColumnValueStore.getS lice(AstyanaxOrderedKeyColumnValueStore.java:148) at com.thinkaurelius.titan.diskstorage.keycolumnvalue.BufferedKeyColumnValueStore.getSlice(Buffer edKeyColumnValueStore.java:36) at com.thinkaurelius.titan.diskstorage.locking.consistentkey.ConsistentKeyLockStore.getSlice(Cons istentKeyLockStore.java:82) at com.thinkaurelius.titan.graphdb.database.StandardTitanGraph.appendResults(StandardTitanGraph.j ava:602) ... 18 more Caused by: com.netflix.astyanax.connectionpool.exceptions.BadRequestException: BadRequestException: [host =cirrus1(10.1.5.44):9160, latency=0(0), attempts=1] InvalidRequestException(why:Keyspace Recommender does not exist) at com.netflix.astyanax.thrift.ThriftConverter.ToConnectionPoolException(ThriftConverter.java:159 ) at com.netflix.astyanax.thrift.AbstractOperationImpl.execute(AbstractOperationImpl.java:60) at com.netflix.astyanax.thrift.ThriftColumnFamilyQueryImpl$1$2.execute(ThriftColumnFamilyQueryImp l.java:196) at com.netflix.astyanax.thrift.ThriftColumnFamilyQueryImpl$1$2.execute(ThriftColumnFamilyQueryImp l.java:188) at com.netflix.astyanax.thrift.ThriftSyncConnectionFactoryImpl$1.execute(ThriftSyncConnectionFact oryImpl.java:131) at com.netflix.astyanax.connectionpool.impl.AbstractExecuteWithFailoverImpl.tryOperation(Abstract ExecuteWithFailoverImpl.java:52) at com.netflix.astyanax.connectionpool.impl.AbstractHostPartitionConnectionPool.executeWithFailov er(AbstractHostPartitionConnectionPool.java:229) at com.netflix.astyanax.thrift.ThriftColumnFamilyQueryImpl$1.execute(ThriftColumnFamilyQueryImpl. java:186) at com.thinkaurelius.titan.diskstorage.cassandra.astyanax.AstyanaxOrderedKeyColumnValueStore.getS lice(AstyanaxOrderedKeyColumnValueStore.java:145) ... 21 more Caused by: InvalidRequestException(why:Keyspace Recommender does not exist) at org.apache.cassandra.thrift.Cassandra$get_slice_result.read(Cassandra.java:7280) at org.apache.thrift.TServiceClient.receiveBase(TServiceClient.java:78) at org.apache.cassandra.thrift.Cassandra$Client.recv_get_slice(Cassandra.java:552) at org.apache.cassandra.thrift.Cassandra$Client.get_slice(Cassandra.java:536) at com.netflix.astyanax.thrift.ThriftColumnFamilyQueryImpl$1$2.internalExecute(ThriftColumnFamily QueryImpl.java:201) at com.netflix.astyanax.thrift.ThriftColumnFamilyQueryImpl$1$2.internalExecute(ThriftColumnFamily QueryImpl.java:188) at com.netflix.astyanax.thrift.AbstractOperationImpl.execute(AbstractOperationImpl.java:55) ... 28 more Cassandra's log: WARN [ScheduledTasks:1] 2013-02-07 17:46:24,935 StorageService.java (line 2855) Flushing CFS(Keyspace='R ecommender', ColumnFamily='edgestore') to relieve memory pressure INFO [ScheduledTasks:1] 2013-02-07 17:46:24,935 ColumnFamilyStore.java (line 659) Enqueuing flush of Mem table-edgestore@2032656921(3689547/40713915 serialized/live bytes, 165613 ops) INFO [FlushWriter:237] 2013-02-07 17:46:24,961 Memtable.java (line 264) Writing Memtable-edgestore@20326 56921(3689547/40713915 serialized/live bytes, 165613 ops) INFO [FlushWriter:237] 2013-02-07 17:46:29,798 Memtable.java (line 305) Completed flushing /home/apollo/ cassandra/data/Recommender/edgestore/Recommender-edgestore-hf-7-Data.db (2143580 bytes) for commitlog pos ition ReplayPosition(segmentId=1360013782638, position=19121495) INFO [MemoryMeter:1] 2013-02-07 17:49:39,624 Memtable.java (line 213) CFS(Keyspace='Recommender', Column Family='edgestore') liveRatio is 9.312177865096587 (just-counted was 9.312177865096587). calculation too k 868ms for 11757 columns INFO [Thrift:1977] 2013-02-07 17:58:01,292 MigrationManager.java (line 174) Drop Keyspace 'Recommender' INFO [MigrationStage:1] 2013-02-07 17:58:01,294 ColumnFamilyStore.java (line 659) Enqueuing flush of Mem table-schema_keyspaces@937719474(0/0 serialized/live bytes, 1 ops) INFO [FlushWriter:238] 2013-02-07 17:58:01,362 Memtable.java (line 264) Writing Memtable-schema_keyspace s@937719474(0/0 serialized/live bytes, 1 ops) INFO [FlushWriter:238] 2013-02-07 17:58:01,404 Memtable.java (line 305) Completed flushing /home/apollo/ cassandra/data/system/schema_keyspaces/system-schema_keyspaces-hf-96-Data.db (61 bytes) for commitlog pos ition ReplayPosition(segmentId=1360013782638, position=21758272) INFO [MigrationStage:1] 2013-02-07 17:58:01,513 ColumnFamilyStore.java (line 659) Enqueuing flush of Mem table-schema_columnfamilies@1656096012(0/0 serialized/live bytes, 1 ops) INFO [FlushWriter:238] 2013-02-07 17:58:01,513 Memtable.java (line 264) Writing Memtable-schema_columnfa milies@1656096012(0/0 serialized/live bytes, 1 ops) INFO [FlushWriter:238] 2013-02-07 17:58:01,519 Memtable.java (line 305) Completed flushing /home/apollo/ cassandra/data/system/schema_columnfamilies/system-schema_columnfamilies-hf-302-Data.db (61 bytes) for co mmitlog position ReplayPosition(segmentId=1360013782638, position=21758674) INFO [CompactionExecutor:442] 2013-02-07 17:58:01,531 CompactionTask.java (line 109) Compacting [SSTable Reader(path='/home/apollo/cassandra/data/system/schema_keyspaces/system-schema_keyspaces-hf-96-Data.db'), SSTableReader(path='/home/apollo/cassandra/data/system/schema_keyspaces/system-schema_keyspaces-hf-95-Da ta.db'), SSTableReader(path='/home/apollo/cassandra/data/system/schema_keyspaces/system-schema_keyspaces- hf-94-Data.db'), SSTableReader(path='/home/apollo/cassandra/data/system/schema_keyspaces/system-schema_ke yspaces-hf-93-Data.db')] INFO [MigrationStage:1] 2013-02-07 17:58:01,596 ColumnFamilyStore.java (line 659) Enqueuing flush of Mem table-schema_columns@1442995080(0/0 serialized/live bytes, 1 ops) INFO [FlushWriter:238] 2013-02-07 17:58:01,597 Memtable.java (line 264) Writing Memtable-schema_columns@ 1442995080(0/0 serialized/live bytes, 1 ops) INFO [FlushWriter:238] 2013-02-07 17:58:01,722 Memtable.java (line 305) Completed flushing /home/apollo/ cassandra/data/system/schema_columns/system-schema_columns-hf-63-Data.db (61 bytes) for commitlog positio n ReplayPosition(segmentId=1360013782638, position=21759634) INFO [CompactionExecutor:442] 2013-02-07 17:58:01,746 CompactionTask.java (line 221) Compacted to [/home /apollo/cassandra/data/system/schema_keyspaces/system-schema_keyspaces-hf-97-Data.db,]. 870 to 309 (~35% of original) bytes for 2 keys at 0.001371MB/s. Time: 215ms. INFO [MigrationStage:1] 2013-02-07 17:58:01,862 ColumnFamilyStore.java (line 659) Enqueuing flush of Mem table-titan_ids@1923920972(2304/2880 serialized/live bytes, 36 ops) INFO [FlushWriter:238] 2013-02-07 17:58:01,862 Memtable.java (line 264) Writing Memtable-titan_ids@19239 20972(2304/2880 serialized/live bytes, 36 ops) INFO [FlushWriter:238] 2013-02-07 17:58:01,914 Memtable.java (line 305) Completed flushing /home/apollo/ cassandra/data/Recommender/titan_ids/Recommender-titan_ids-hf-1-Data.db (870 bytes) for commitlog positio n ReplayPosition(segmentId=1360013782638, position=21759634) INFO [MigrationStage:1] 2013-02-07 17:58:01,916 ColumnFamilyStore.java (line 659) Enqueuing flush of Mem table-propertyindex_lock_@540683493(840/1050 serialized/live bytes, 28 ops) INFO [FlushWriter:238] 2013-02-07 17:58:01,971 Memtable.java (line 264) Writing Memtable-propertyindex_l ock_@540683493(840/1050 serialized/live bytes, 28 ops) INFO [FlushWriter:238] 2013-02-07 17:58:02,027 Memtable.java (line 305) Completed flushing /home/apollo/ cassandra/data/Recommender/propertyindex_lock_/Recommender-propertyindex_lock_-hf-1-Data.db (650 bytes) f or commitlog position ReplayPosition(segmentId=1360013782638, position=21759634) INFO [MigrationStage:1] 2013-02-07 17:58:02,047 ColumnFamilyStore.java (line 659) Enqueuing flush of Mem table-edgestore@2005322361(1191757/13872316 serialized/live bytes, 53956 ops) INFO [FlushWriter:238] 2013-02-07 17:58:02,050 Memtable.java (line 264) Writing Memtable-edgestore@20053 22361(1191757/13872316 serialized/live bytes, 53956 ops) INFO [FlushWriter:238] 2013-02-07 17:58:02,134 Memtable.java (line 305) Completed flushing /home/apollo/ cassandra/data/Recommender/edgestore/Recommender-edgestore-hf-8-Data.db (720306 bytes) for commitlog posi tion ReplayPosition(segmentId=1360013782638, position=21760036) INFO [CompactionExecutor:443] 2013-02-07 17:58:02,135 CompactionTask.java (line 109) Compacting [SSTable Reader(path='/home/apollo/cassandra/data/Recommender/edgestore/Recommender-edgestore-hf-6-Data.db'), SSTa bleReader(path='/home/apollo/cassandra/data/Recommender/edgestore/Recommender-edgestore-hf-8-Data.db'), S STableReader(path='/home/apollo/cassandra/data/Recommender/edgestore/Recommender-edgestore-hf-5-Data.db') , SSTableReader(path='/home/apollo/cassandra/data/Recommender/edgestore/Recommender-edgestore-hf-7-Data.d b')] INFO [MigrationStage:1] 2013-02-07 17:58:02,160 ColumnFamilyStore.java (line 659) Enqueuing flush of Mem table-propertyindex@1052449648(243223/8141246 serialized/live bytes, 8387 ops) INFO [FlushWriter:238] 2013-02-07 17:58:02,160 Memtable.java (line 264) Writing Memtable-propertyindex@1 052449648(243223/8141246 serialized/live bytes, 8387 ops) INFO [FlushWriter:238] 2013-02-07 17:58:02,223 Memtable.java (line 305) Completed flushing /home/apollo/ cassandra/data/Recommender/propertyindex/Recommender-propertyindex-hf-3-Data.db (301191 bytes) for commit log position ReplayPosition(segmentId=1360013782638, position=21760036) INFO [CompactionExecutor:443] 2013-02-07 17:58:05,032 CompactionTask.java (line 221) Compacted to [/home /apollo/cassandra/data/Recommender/edgestore/Recommender-edgestore-hf-9-Data.db,]. 17,110,084 to 16,336, 307 (~95% of original) bytes for 78,555 keys at 5.377810MB/s. Time: 2,897ms. INFO [CompactionExecutor:444] 2013-02-07 21:36:21,419 AutoSavingCache.java (line 268) Saved KeyCache (35 939 items) in 31 ms INFO [CompactionExecutor:445] 2013-02-08 01:36:21,435 AutoSavingCache.java (line 268) Saved KeyCache (35 939 items) in 37 ms INFO [CompactionExecutor:446] 2013-02-08 05:36:21,447 AutoSavingCache.java (line 268) Saved KeyCache (40 902 items) in 38 ms INFO [CompactionExecutor:447] 2013-02-08 09:36:21,478 AutoSavingCache.java (line 268) Saved KeyCache (40 902 items) in 59 ms