Super columns suffer from a number of problems, not least of which is that it is necessary for Cassandra to deserialze all of the sub-columns of a super column when querying (even if the result will only return a small subset). As a result, there is a practical limit to the number of sub-columns per … Read more
No, there is no default value in Cassandra. Further more, setting a column value to null means removing it
Client sends the data to a random node It might seem that way, but there is actually a non-random way that your driver picks a node to talk to. This node is called a “coordinator node” and is typically chosen based-on having the least (closest) “network distance.” Client requests can really be sent to any … Read more
There is no way to change a primary key, as it defines how your data is physically stored. You can create a new table with the new primary key, copy data from the old one, and then drop the old table.
I think the issue was the result of having a previous installation that wasn’t properly uninstalled. My user .cassandra directory had some default configs, that must have been for a different version, and prevented cqlsh from starting. rm -Rf ~/.cassandra After that, I could run cqlsh properly. $ bin/cqlsh Connected to Test Cluster at 127.0.0.1:9042. … Read more
I had exactly the same issue: Can’t start Cassandra (Single-Node Cluster on CentOS7) If it is an option for you, using Java 8, instead of 9, is the simplest way to solve the issue.
You can use the TimeUUID type in Cassandra, which backs a Type 1 UUID. This uses the current time and the creator’s MAC address and a sequence number. If the TimeUUID number is generated correctly this can be done with zero collisions (you can use the CQL now() method or insert your own, the java … Read more
cqlsh -e “select * from ks.table limit 1;” > ~/output
Since you don’t care about the data, removing files from \data\commitlogs should be easiest solution.
There are a couple of ways to go about this. From within cqlsh, you can simply show version. aploetz@cqlsh> show version [cqlsh 5.0.1 | Cassandra 2.1.8 | CQL spec 3.2.0 | Native protocol v3] However, that only works from within cqlsh. Fortunately, you can also query system.local for that information as well. aploetz@cqlsh> SELECT cql_version … Read more