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https://issues.apache.org/jira/browse/CASSANDRA-44?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12697212#action_12697212
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Jonathan Ellis commented on CASSANDRA-44:
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Maintaining CF definitions looks like a good use case for Zookeeper to me. We
could do it like this:
- on startup, a cassandra node must contact zookeeper and read the column
family data. this is the only time it will abort if ZK is not available.
- when an operation is requested for a columnfamily that does not exist, the
node checks zookeeper to see if that column has been added
- additionally, we can check every hour or so for new columns and removed
columns. so removed CFs could accept ops for a while after officially being
"removed."
- adding and removing CFs would be done with a web interface. (I'm strongly
in favor of moving the web UI to Jython; it's much better suited for this than
raw Java.)
At the znode level, we would have
/columfamilies/[tablename]/[columnfamily1|columnfamily2|...] where the
columnfamily znodes contain the sort information and any other attributes that
was previously being stored in TableMetadata.
Notes to keep adminning a ZK ensemble relatively painless:
- use the Cassandra seed nodes as the ZK ensemble members. (Both seed nodes
and ZK require a relatively small number of machines in the cluster to
participate.) We can ship a config file so that cassandra will continue to
Just Work on localhost.
Thoughts?
> It isn't possible to easily add new column families to an existing cluster
> --------------------------------------------------------------------------
>
> Key: CASSANDRA-44
> URL: https://issues.apache.org/jira/browse/CASSANDRA-44
> Project: Cassandra
> Issue Type: Bug
> Reporter: Eric Evans
> Priority: Minor
>
> Once a cluster is created, adding new column families to the configuration
> file will not result in their creation. See also:
> http://groups.google.com/group/cassandra-dev/browse_thread/thread/78598f808e10b984/fe26cae1689d5474
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