title: Cassandra - Composite Partition Keys and Performance
body: <p>I am working on the keyspace and tables for a Cassandra environment. I understand the size limitations of Cassandra and dealing with Partition keys to keep it optimized. However, I am having a disagreement with a developer regarding how to handle the keys. Is there any downside in having a key that would include a large number of data rather than a small amount of data. For example,</p>
  
  <p>I have 100k records. I can create a key that will partition this into 10k; I could also create a key that will partition this into 10 records (by day). So either I store 10k and 10 partitions or 10 records and 10,000 partitions.</p>