Re: columns disappearing intermittently
Since you are doing QUORAM, looks like the column is not found in 2 machines. Did you switch to vnodes? Try to see which machines are responding when you get the column and when not. Might be able to identity the problem On Wed, Jul 3, 2013 at 4:56 AM, Eric Stevens wrote: > I wonder if one particular node is having trouble; when you notice the > missing column, what happens if you execute the read manually from cqlsh or > cassandra-cli independently directly on each node? > > > On Wed, Jul 3, 2013 at 2:00 AM, Blake Eggleston wrote: > >> Hi All, >> >> We're having a problem with our cassandra cluster and are at a loss as to >> the cause. >> >> We have what appear to be columns that disappear for a little while, then >> reappear. The rest of the row is returned normally during this time. This >> is, of course, very disturbing, and is wreaking havoc with our application. >> >> A bit more info about what's happening: >> >> We are repeatedly executing the same query against our cluster. Every so >> often, one of the columns will disappear from the row and will remain gone >> for some time. Then after continually executing the same query, the column >> will come back. The queries are being executed against a 3 node cluster, >> with a replication factor of 3, and all reads and writes are done with a >> quorum consistency level. >> >> We upgraded from cassandra 1.1.12 to 1.2.6 last week, but only started >> seeing issues this morning. >> >> Has anyone had a problem like this before, or have any idea what might be >> causing it? > > >
Re: Added nodes to cluster, authentication stopped working
patch cassandra and remove the code which checks auth :) On Wed, Jul 3, 2013 at 6:55 AM, Carlos Rolo wrote: > Hi all, > > I have a Cassandra Cluster running and we recently duplicated the cluster. > > After following all the steps, the cassandra clients started failing with > the following message: > > "AuthenticationException(why='Username and/or password are incorrect')" > > The problem is that even I can't login to the CQL shell and check the > users, since it says (even with the correct username/password) that 'You > have to be logged in and not anonymous to perform this request'. > > When I created the Cluster I disabled the 'cassandra' superuser and now I > can't do anything on my Cluster. > > Is there any method to reset a user and/or password, or recreate a new > superuser?? > > Otherwise I need to drop all the data from the cluster... Since even > disabling authentication and authorization my clients give errors writting > data. >
Re: column sort order and reversed sort performance question
One of the reasons of using reverse order is to skip the tombstones while doing a range query. Here is an example. * Lets say we want to read all the data which is between 10 minutes old upto 60 minute old. If the data is stored from old to new in an sstable, then we have to go over all the tombstones before we get any column which is live. All the lazy iterators on the column will start with giving columns which are 60 minutes old, 59 minutes old and so on. They all will keep getting tombstones and we will not find any live column till we reach 11 or 12 minute. SO this way we have to go over all the data and tombstones between 60 and 12(if non deleted columns are found at 12 minute). Whereas, if we store the data from new to old, when we iterate over columns, we will get newer columns first which will have been tombstones and we will find live columns which we can return. But if there is less columns than we want, then the way we store data does not matter. Because we anyway have to go over all the columns from 10 to 60 minutes. * On Wed, Jul 3, 2013 at 10:11 AM, Robert Coli wrote: > On Wed, Jul 3, 2013 at 6:02 AM, Hiller, Dean wrote: > > > > We loaded 5 million columns into a single row and when accessing the > first 30k and last 30k columns we saw no performance difference. We tried > just loading 2 rows from the beginning and end and saw no performance > difference. I am sure reverse sort is there for a reason though. In what > context do you actually see a performance difference with reverse sort??? > > > http://thelastpickle.com/2011/10/03/Reverse-Comparators/ > " > When a query does not specify a start column (and does not specify > reversed) the server can just start reading columns from the start without > having to worry about finding the right place to start. This is exactly > what we can do for the Descending CF. > > For the regular Ascending CF we need to specify reversed, so the server > must read the row index and work out which column is column count from the > end of the row. > > There is no comparison really. > " > > =Rob > >
Re: CassandraDaemon - recent unsafe memory access operation in compiled Java code
have u dropped the JNA jar? Looks like the mmap is failing. On Fri, Jul 5, 2013 at 8:15 AM, Glyn Davies wrote: > > > Hi, > > Just starting to experiment with Cassandra, and have hit an early snag. > > I'm using 1.2.6 on Ubuntu AWS m1.xlarge instances with the Datastax > Community package and have tried using Java versions jdk1.7.0_25 > jre1.6.0_45 > Also testing with and without libjna-java > > However, something has triggered a bug in the CassandraDaemon: > > ERROR [COMMIT-LOG-ALLOCATOR] 2013-07-05 15:00:51,663 > CassandraDaemon.java (line 192) Exception in thread > Thread[COMMIT-LOG-ALLOCATOR,5,main] > java.lang.InternalError: a fault occurred in a recent unsafe memory access > operation in compiled Java code > at > org.apache.cassandra.db.commitlog.CommitLogSegment.(CommitLogSegment.java:126) > at > org.apache.cassandra.db.commitlog.CommitLogSegment.freshSegment(CommitLogSegment.java:81) > at > org.apache.cassandra.db.commitlog.CommitLogAllocator.createFreshSegment(CommitLogAllocator.java:250) > at > org.apache.cassandra.db.commitlog.CommitLogAllocator.access$500(CommitLogAllocator.java:48) > at > org.apache.cassandra.db.commitlog.CommitLogAllocator$1.runMayThrow(CommitLogAllocator.java:104) > at > org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:28) > at java.lang.Thread.run(Unknown Source) > > This brought two nodes down out of a three node cluster – using QUORUM > write with 3 replicas. > Restarting the node replays this error, so I have the system in a 'stable' > unstable state – which is probably a good place for trouble shooting. > > Presumably something a client wrote triggered this situation, and the > other third node was to be the final replication point – and is thus still > up. > > Any suggestions on next steps? > I've had a good google for the error combinations, but didn't find any > hits. > > Thanks, > > Glyn > > __ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please visit http://www.symanteccloud.com > __ >
I am trying to use https://github.com/boneill42/naughty-or-nice to run.
Greetings, I am new to cassandra, eclipse, git and maven I am trying to use https://github.com/boneill42/naughty-or-nice to run. I have am ubuntu 12.04 VM running as well as the CQL and cli for cassandra 1.2.6.and checked out. I have eclipse 4.3 with git and market place installed and checked out. I am not sure how to create a project in eclipse that brings in https://github.com/boneill42/naughty-or-nice. I am inexperienced with git and maven. I am not sure how to get clients (java) for cassandra. Unfortunatly I need step-by-step assistance. I am commited to moving to cassandra and storm ... I aver much appreciate your assistance! Chris
Re: Installing specific version
On ubuntu it is: apt-get install cassandra=1.2.4 So should be similar for debian Ben Bromhead Instaclustr | www.instaclustr.com | @instaclustr | +61 415 936 359 On 05/07/2013, at 10:59 PM, Kais Ahmed wrote: > Hi ben, > > You can get it from http://archive.apache.org/dist/cassandra/ > > > 2013/7/5 Ben Gambley > Hi all > > Can anyone point me in the right direction for installing a specific version > from datastax repo, we need 1.2.4 to keep consistent with our qa environment. > > It's for a new prod cluster , on Debian 6. > > I thought it may be a value in /etc/apt/source.list ? > > The latest 1.2.6 does not appear compatible with our phpcassa thrift drivers. > > After many late nights my google ability seems to have evaporated! > > Cheers > Ben > >
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