Cassandra RandomPartitioner on version 1.2.3

3
votes

Im installing Cassandra 1.2.3 on debian using apt, I was previously using a tarball 1.1.7 install. After install i'm changing the partitioner from Murmur3Partitioner to RandomPartitioner in cassandra.yaml as follows:

partitioner: org.apache.cassandra.dht.RandomPartitioner

Then on starting i'm seeing incompatible system keyspace errors as follows:

ERROR 18:22:11,465 Cannot open /var/lib/cassandra/data/system/schema_keyspaces/system-schema_keyspaces-ib-1; partitioner org.apache.cassandra.dht.Murmur3Partitioner does not match system partitioner org.apache.cassandra.dht.RandomPartitioner. Note that the default partitioner starting with Cassandra 1.2 is Murmur3Partitioner, so you will need to edit that to match your old partitioner if upgrading. Service exit with a return value of 1

How can I set the system keyspace to be RandomPartitioner? I have tried purging the data folder, apt-get remove, also apt-get purge then re-installing, changing to RandomPartitioner then starting cassandra but it is still failing. I've also replicated this on my ubuntu desktop so im thinking im doing something wrong here.

Any help is appreciated!

Cheers

Sam

2
cassandra

2 Answers

9
votes

The partitioner cannot be changed once Cassandra has started for the first time. This error is showing that the data directory was initialized with Murmur3Partitioner but you're starting it using RandomPartitioner.

If you're trying to upgrade your data from your 1.1 install, Cassandra isn't reading from the right place. Adjust your data directory to use your 1.1 directory and it should start with partitioner set to RandomPartitioner.

If you're trying to start with no data, stop Cassandra, remove /var/lib/cassandra/* and start it again. Note you need to remove the commitlog directory as well as the data directory.

2
votes

I got a similar error as reported by Sam when I did a

[root@fedora user]# dse cassandra. To correct the problem I did:

  1. [root@fedora user]# vi /etc/dse/cassandra/cassandra.yaml
  2. In the cassandra.yaml file made the following change

Commented out "# partitioner: org.apache.cassandra.dht.Murmur3Partitioner" and replaced it with "partitioner: org.apache.cassandra.dht.RandomPartitioner" 3. Saved the change in cassandra.yaml

Hope this helps.

Mayukh.