Hi Alex,

Do you have SELinux on? If you do, before we proceed, could you please turn it off and see if you still get the error. It's known to cause all kinds of obscure permission-related problems, so it's better to rule it out from the start.

Thanks.

Elena,

I disabled SeLinux and ran into yet another problem:

create table t1 ( rowkey varchar(36) primary key, data1 varchar(60), data2 bigint ) engine=cassandra thrift_host='localhost' keyspace='xxx' column_family='xxx';

When in fact I created column family xxx under xxx keyspace.

Please note that I'm using cassandra 1.2 - I've heard that there issues with this release of Cassandra 1.2. Any ETA when it will be fixed?

Hi Alex,

What problem did you run into with the DDL above? I suppose you forgot to paste the error message.

Here we go:

MariaDB [xxx]> create table t1 ( rowkey varchar(36) primary key, data1 varchar(60), data2 bigint ) engine=cassandra thrift_host='localhost' keyspace='xxx' column_family='xxx';

ERROR 1429 (HY000): Unable to connect to foreign data source: Column family xxx not found in keyspace xxx

Also pls check http://www.slideshare.net/SergeyPetrunya/mysqlconf2013-mariadbcassandrainteroperability slide 11 out 34 there seems to be a know problem with Cassandra 1.2 integration

Right. I'll reassign it to Sergei Petrunia so that you could get firsth-hand information regarding plans to fix it.

Thx a lot, please keep us posted, we have a meetup scheduled specifically to discuss and demo MariaDB and Cassandra integration http://www.meetup.com/mysql-silicon-valley/events/119357352/ fixing this issue will greatly help to promote MariaDB.

Thx in advance

Alex -

Hello,

This seems to be the problem with data model change in Cassandra 1.2.

Cassandra 1.2 seems to have a split in the data model. One can have either:

1. Old-style column family (that one creates with cassandra-cli
or in CQL with "WITH COMPACT STORAGE" attribute)

2. New-style column family (created with CREATE TABLE in CQL-3)

Cassandra itself seems to be poor at interoperability: Thrift clients cannot
access new-style column families. On the other hand, CQL-3 requires that all
columns are pre-defined, which means you cannot use CQL-3 to read data that
was inserted through Thrift.

Cassandra SE uses Thrift and so is a victim of this mess.

I have looked at what is required to update Cassandra SE. It seems that

• We will still need to support Thrift (because some data can only be accessed through Thrift API)
• We will need to use CQL to access new-style CQL column families.

Thrift API has a execute_cql3() method, but the problem with it is that it is not possible to stream the resultset. The entire resultset will be materialized on a node in Cassandra cluster, then sent to MariaDB node, where thrift library will also materialize it before returning control to Cassandra SE. This means that attempt to run "SELECT * FROM cassandra_table" (without the implied "LIMIT 10K") will kill the node. (pure Thrift API supports streaming, current Cassandra SE will run this SELECT * query without consuming all of the memory).

Cassandra 1.2 has a new network protocol for CQL. The protocol supports streaming. Datastax does not provide a C++ client library, but it seems there is a 3rd-party client library: https://github.com/mstump/libcql. I've just found it by googling so I don't have an idea whether this library is sufficient for Cassandra SE.

Interesting read... It seems, DataStax intends to make a C++ client library: https://github.com/mstump/libcql/issues/16#issuecomment-19923916 ... and it is not clear how that will relate to libcql.

Sergei,

Any updates on this bug - I have meetup coming up at Silicon Valley MySQL user group discussing this feature - MariaDB and Cassandra integration. Do we have an ETA on this by any chance?

Unfortunately, I cannot get any resources to continue to work on this. Changing the status to "Wont fix", because currently there are no plans for further development of Cassandra SE.