Yes, there is memory overhead for each column family, effectively limiting the number of column families. The general wisdom is that you should limit yourself to a few hundred.
Robert On Feb 29, 2016, at 10:30 AM, Fernando Jimenez <fernando.jime...@wealth-port.com<mailto:fernando.jime...@wealth-port.com>> wrote: Hi all I have a use case for Cassandra that would require creating a large number of column families. I have found references to early versions of Cassandra where each column family would require a fixed amount of memory on all nodes, effectively imposing an upper limit on the total number of CFs. I have also seen rumblings that this may have been fixed in later versions. To put the question to rest, I have setup a DSE sandbox and created some code to generate column families populated with 3,000 entries each. Unfortunately I have now hit this issue: https://issues.apache.org/jira/browse/CASSANDRA-9291 So I will have to retest against Cassandra 3.0 instead However, I would like to understand the limitations regarding creation of column families. * Is there a practical upper limit? * is this a fixed limit, or does it scale as more nodes are added into the cluster? * Is there a difference between one keyspace with thousands of column families, vs thousands of keyspaces with only a few column families each? I haven’t found any hard evidence/documentation to help me here, but if you can point me in the right direction, I will oblige and RTFM away. Many thanks for your help! Cheers FJ
