Thanks for the reply Sylvain! A couple of follow-up questions: i. The second stack in my mail originated at a getRow() call. What could be the cause of that? I am assuming data retrieval should not cause any issues, unless data was stored in incorrect order and I don't know if that is possible through the API..
ii. I am also seeing some sporadic cases where a single column cas() update is hitting this same issue (the bug you mentioned) as multiple columns, do you see any reason for that happening? I am yet to investigate this though. Thank you, Soumava On Mon, Jul 22, 2013 at 12:11 AM, Sylvain Lebresne <sylv...@datastax.com>wrote: > This is a bug really: https://issues.apache.org/jira/browse/CASSANDRA-5786 > . > > This should get fixed in the next beta of 2.0, but if you really want to > test CAS updates in the meantime, you'll have to provide the columns in > (column family comparator) sorted order to the thrift cas() method. > > -- > Sylvain > > > On Sun, Jul 21, 2013 at 1:22 PM, Soumava Ghosh <soum...@cs.utexas.edu>wrote: > >> Hi, >> >> I'm taking a look at the Check and Set functionalities provided by the >> cas() API provided by cassandra 2.0 (the code available on git). I'm >> running a few tests on a small sized cluster (replication factor 3, >> consistency level quorum) with a few clients. I've observed a lot of cases >> seem to hit the TimedOutException while paxos is in progress. On inspection >> of the server side logs the following stack was seen: >> >> ERROR [Thread-582] 2013-07-21 01:17:46,169 CassandraDaemon.java (line >> 196) Exception in thread Thread[Thread-582,5,main] >> java.lang.AssertionError: Added column does not sort as the last column >> at >> org.apache.cassandra.db.ArrayBackedSortedColumns.addColumn(ArrayBackedSortedColumns.java:115) >> at >> org.apache.cassandra.db.ColumnFamily.addColumn(ColumnFamily.java:117) >> at >> org.apache.cassandra.db.ColumnFamilySerializer.deserialize(ColumnFamilySerializer.java:119) >> at >> org.apache.cassandra.db.ColumnFamilySerializer.deserialize(ColumnFamilySerializer.java:96) >> at >> org.apache.cassandra.db.ColumnFamilySerializer.deserialize(ColumnFamilySerializer.java:91) >> at >> org.apache.cassandra.service.paxos.Commit$CommitSerializer.deserialize(Commit.java:139) >> at >> org.apache.cassandra.service.paxos.Commit$CommitSerializer.deserialize(Commit.java:128) >> at org.apache.cassandra.net.MessageIn.read(MessageIn.java:99) >> at >> org.apache.cassandra.net.IncomingTcpConnection.receiveMessage(IncomingTcpConnection.java:175) >> at >> org.apache.cassandra.net.IncomingTcpConnection.handleModernVersion(IncomingTcpConnection.java:135) >> at >> org.apache.cassandra.net.IncomingTcpConnection.run(IncomingTcpConnection.java:82) >> >> I was updating multiple columns using the same cas() call, and looking at >> the assert (code below) I added code to sort them before sending. >> However, now I'm seeing the same issue *even with single column* cas() >> calls. >> >> int c = internalComparator().compare(columns.get(getColumnCount() >> - 1).name(), column.name()); >> // note that we want an assertion here (see addColumn javadoc), >> but we also want that if >> // assertion are disabled, addColumn works correctly with >> unsorted input >> assert c <= 0 : "Added column does not sort as the " + (reversed >> ? "first" : "last") + " column"; >> >> I have also seen this error occur in the getRow() path, as below: >> >> java.lang.AssertionError: Added column does not sort as the last column >> at >> org.apache.cassandra.db.ArrayBackedSortedColumns.addColumn(ArrayBackedSortedColumns.java:115) >> at >> org.apache.cassandra.db.ColumnFamily.addColumn(ColumnFamily.java:117) >> at >> org.apache.cassandra.db.ColumnFamily.addAtom(ColumnFamily.java:151) >> at >> org.apache.cassandra.db.CollationController.collectTimeOrderedData(CollationController.java:95) >> at >> org.apache.cassandra.db.CollationController.getTopLevelColumns(CollationController.java:57) >> at >> org.apache.cassandra.db.ColumnFamilyStore.getTopLevelColumns(ColumnFamilyStore.java:1452) >> at >> org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1281) >> at >> org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1195) >> at org.apache.cassandra.db.Table.getRow(Table.java:331) >> at >> org.apache.cassandra.db.SliceByNamesReadCommand.getRow(SliceByNamesReadCommand.java:55) >> at >> org.apache.cassandra.service.StorageProxy$LocalReadRunnable.runMayThrow(StorageProxy.java:1288) >> at >> org.apache.cassandra.service.StorageProxy$DroppableRunnable.run(StorageProxy.java:1813) >> 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) >> >> Could someone provide me a little more clarity about what the context of >> the error is and what the client needs to do to fix it? I understand that >> running with assertions disabled would do away with this error, but i'd >> like to know if there is a proper way to fix this. Moreover, what could >> possibly be going wrong in the get path that is hitting this issue? >> >> Some guidance, on the fact that whether it is expected that the client >> sort the columns before calling the API with multiple columns, would be >> really appreciated. >> >> Thanks, >> Soumava >> > >
