#1 The cause of this problem is a CREATE TABLE statement collision. Do not generate tables dynamically from multiple clients, even with IF NOT EXISTS. First thing you need to do is fix your code so that this does not happen. Just create your tables manually from cqlsh allowing time for the schema to settle.
#2 Here's the fix: 1) Change your code to not automatically re-create tables (even with IF NOT EXISTS). 2) Run a rolling restart to ensure schema matches across nodes. Run nodetool describecluster around your cluster. Check that there is only one schema version. ON EACH NODE: 3) Check your filesystem and see if you have two directories for the table in question in the data directory. If THERE ARE TWO OR MORE DIRECTORIES: 4)Identify from schema_column_families which cf ID is the "new" one (currently in use). cqlsh -e "select * from system.schema_column_families"|grep <table name> 5) Move the data from the "old" one to the "new" one and remove the old directory. 6) If there are multiple "old" ones repeat 5 for every "old" directory. 7) run nodetool refresh IF THERE IS ONLY ONE DIRECTORY: No further action is needed. All the best, [image: datastax_logo.png] <http://www.datastax.com/> Sebastián Estévez Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com [image: linkedin.png] <https://www.linkedin.com/company/datastax> [image: facebook.png] <https://www.facebook.com/datastax> [image: twitter.png] <https://twitter.com/datastax> [image: g+.png] <https://plus.google.com/+Datastax/about> <http://feeds.feedburner.com/datastax> <http://goog_410786983> <http://www.datastax.com/gartner-magic-quadrant-odbms> DataStax is the fastest, most scalable distributed database technology, delivering Apache Cassandra to the world’s most innovative enterprises. Datastax is built to be agile, always-on, and predictably scalable to any size. With more than 500 customers in 45 countries, DataStax is the database technology and transactional backbone of choice for the worlds most innovative companies such as Netflix, Adobe, Intuit, and eBay. On Tue, Nov 10, 2015 at 6:09 PM, Maciek Sakrejda <mac...@heroku.com> wrote: > Oh and for what it's worth, I've also looked through the logs for this > node, and the oldest error in the logs seems to be: > > [0000] 06 Nov 22:10:53.260 * pri=ERROR t=Thrift:16 > at=CustomTThreadPoolServer.run Error occurred during processing of message. > java.lang.RuntimeException: java.util.concurrent.ExecutionException: > java.lang.RuntimeException: > org.apache.cassandra.exceptions.ConfigurationException: Column family ID > mismatch (found 3ed23e80-84d3-11e5-83b3-0fc0205655f5; expected > 3ecce750-84d3-11e5-bdd9-dd7717dcdbd5) > > Then the logs show a compaction, and then the UnknownColumnFamilyException > starts occuring. > >
