Using collections

Collection types provide an improved way of handling tasks, such as building multiple email address capability into tables.

Apache Cassandra includes collection types that provide an improved way of handling tasks, such as building multiple email address capability into tables. Observe the following limitations of collections:

  • The maximum size of an item in a collection is 64K or 2B, depending on the native protocol version.
  • Keep collections small to prevent delays during querying because Cassandra reads a collection in its entirety. The collection is not paged internally.

    As discussed earlier, collections are designed to store only a small amount of data.

  • Never insert more than 64K items in a collection.

    If you insert more than 64K items into a collection, only 64K of them will be queryable, resulting in data loss.

Note: For detailed limits on collections, see CQL limits.

You can expire each element of a collection by setting an individual time-to-live (TTL) property.