> but yesterday one of 600 mappers failed > :) > From what I can understand by looking into the C* source, it seems to me that > the problem is caused by a empty (or surprisingly finished?) input buffer (?) > causing token to be set to -1 which is improper for RandomPartitioner: Yes, there is a zero length key which as a -1 token.
> However, I can't figure out what's the root cause of this problem. > Any ideas? mmm, the BulkOutputFormat uses a SSTableSimpleUnsortedWriter and neither of them check for zero length row keys. I would look there first. There is no validation in the AbstractSSTableSimpleWriter, not sure if that is by design or an oversight. Can you catch the zero length key in your map job ? Cheers ----------------- Aaron Morton Freelance Cassandra Consultant New Zealand @aaronmorton http://www.thelastpickle.com On 28/03/2013, at 2:26 PM, Michal Michalski <mich...@opera.com> wrote: > We're streaming data to Cassandra directly from MapReduce job using > BulkOutputFormat. It's been working for more than a year without any > problems, but yesterday one of 600 mappers faild and we got a strange-looking > exception on one of the C* nodes. > > IMPORTANT: It happens on one node and on one cluster only. We've loaded the > same data to test cluster and it worked. > > > ERROR [Thread-1340977] 2013-03-28 06:35:47,695 CassandraDaemon.java (line > 133) Exception in thread Thread[Thread-1340977,5,main] > java.lang.RuntimeException: Last written key > DecoratedKey(5664330507961197044404922676062547179, > 302c6461696c792c32303133303332352c312c646f6d61696e2c756e6971756575736572732c633a494e2c433a6d63635f6d6e635f636172726965725f43656c6c4f6e655f4b61726e6174616b615f2842616e67616c6f7265295f494e2c643a53616d73756e675f47542d49393037302c703a612c673a3133) > >= current key DecoratedKey(-1, ) writing into > /cassandra/production/IndexedValues/production-IndexedValues-tmp-ib-240346-Data.db > at > org.apache.cassandra.io.sstable.SSTableWriter.beforeAppend(SSTableWriter.java:133) > at > org.apache.cassandra.io.sstable.SSTableWriter.appendFromStream(SSTableWriter.java:209) > at > org.apache.cassandra.streaming.IncomingStreamReader.streamIn(IncomingStreamReader.java:179) > at > org.apache.cassandra.streaming.IncomingStreamReader.read(IncomingStreamReader.java:122) > at > org.apache.cassandra.net.IncomingTcpConnection.stream(IncomingTcpConnection.java:226) > at > org.apache.cassandra.net.IncomingTcpConnection.handleStream(IncomingTcpConnection.java:166) > at > org.apache.cassandra.net.IncomingTcpConnection.run(IncomingTcpConnection.java:66) > > > From what I can understand by looking into the C* source, it seems to me that > the problem is caused by a empty (or surprisingly finished?) input buffer (?) > causing token to be set to -1 which is improper for RandomPartitioner: > > public BigIntegerToken getToken(ByteBuffer key) > { > if (key.remaining() == 0) > return MINIMUM; // Which is -1 > return new BigIntegerToken(FBUtilities.hashToBigInteger(key)); > } > > However, I can't figure out what's the root cause of this problem. > Any ideas? > > Of course I can't exclude a bug in my code which streams these data, but - as > I said - it works when loading the same data to test cluster (which has > different number of nodes, thus different token assignment, which might be a > case too). > > Michał
