Cassandra keyspaces and column families are different from regular SQL databases and tables. A partition key row lies completely on a node, and it can have multiple logical rows uniquely identified by the primary key. A column family with one or more clustering columns in its primary key can have multiple logical rows per partition, so these column families are called wide rows. Rows per partition key are sorted based on the clustering columns. While reading records we can only search by either partition key or clustering columns. Secondary index columns can also be used to filter search data. Cassandra, by default, prevents running those queries that involve filtering. LWTs can help to serialize concurrent operations at some performance cost. Multiple related DML statements can be grouped together by BATCH statements. Default batch statements are atomic and are costlier in terms of performance. The UNLOGGED batches could be used if atomicity isn't required and performance is more...