There's a default limit of 2 billion cells (rows * cols) but larger partitions also mean larger indexes and more serialization, repair, compaction and memory ov

There's a default limit of 2 billion cells (rows * cols) but larger partitions also mean larger indexes and more serialization, repair, compaction and memory overhead which doesn't work well with Cassandra's Java/JVM GC requirements. It's getting better but likely will never reach the performance potential of Scylla which is Cassandra reimplemented in C++ with a much better sharded architecture.