ALLOW FILTERING explained

The text discusses Cassandra's ALLOW FILTERING feature and how it affects query performance. It explains that Cassandra requires ALLOW FILTERING for some CQL queries to prevent inefficient resource usage, as the system might need to retrieve all rows from a table before filtering out irrelevant data. The text also highlights the importance of understanding data distribution and making informed decisions when using ALLOW FILTERING or adding indexes to improve query performance. It emphasizes that users should consider their specific use case and choose the appropriate strategy, such as changing the data model, adding an index, or using another table.