I'm testing a Cassandra 0.8.1 setup with SimpleCassie for PHP, and my
get_slice is failing because when I created the keyspace I set it up
like this:
create keyspace armorgames with
strategy_options=[{replication_factor:2}] and placement_strategy =
'org.apache.cassandra.locator.SimpleStrategy';
... in expectation that when this goes into production, we'll have a
second node.
However, in the meantime, I'm just running one node, but now when I run
a get_slice, i get the following error:
ERROR [pool-2-thread-16] 2011-08-12 10:26:39,797 Cassandra.java (line
3041) Internal error processing get_slice
java.lang.IllegalStateException: *replication factor (2) exceeds number
of endpoints (1)*
at
org.apache.cassandra.locator.SimpleStrategy.calculateNaturalEndpoints(SimpleStrategy.java:61)
at
org.apache.cassandra.locator.AbstractReplicationStrategy.getNaturalEndpoints(AbstractReplicationStrategy.java:100)
at
org.apache.cassandra.service.StorageService.getLiveNaturalEndpoints(StorageService.java:1642)
at
org.apache.cassandra.service.StorageService.getLiveNaturalEndpoints(StorageService.java:1636)
at
org.apache.cassandra.service.StorageProxy.fetchRows(StorageProxy.java:511)
at
org.apache.cassandra.service.StorageProxy.read(StorageProxy.java:480)
at
org.apache.cassandra.thrift.CassandraServer.readColumnFamily(CassandraServer.java:109)
at
org.apache.cassandra.thrift.CassandraServer.getSlice(CassandraServer.java:263)
at
org.apache.cassandra.thrift.CassandraServer.multigetSliceInternal(CassandraServer.java:345)
at
org.apache.cassandra.thrift.CassandraServer.get_slice(CassandraServer.java:306)
at
org.apache.cassandra.thrift.Cassandra$Processor$get_slice.process(Cassandra.java:3033)
at
org.apache.cassandra.thrift.Cassandra$Processor.process(Cassandra.java:2889)
at
org.apache.cassandra.thrift.CustomTThreadPoolServer$WorkerProcess.run(CustomTThreadPoolServer.java:187)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:679)
So my first question is how can I get around this, secondly, can I
'alter' a keyspace to change its replication factor on the fly, and what
impact does that have, and third, what's the best practice to handle
this kind of thing gracefully in production if we DID have two nodes and
one needs to be taken offline (or crashes).
Thanks,
Ian
