Cassandra - advantages of custom type

Question

I am planning to use a Java object as a custom type and store it Cassandra. I am taking out 2 data members from the class and making them into primary key and keeping the rest of the data members in the custom type. data members of my class: name, date_of_birth, occupation, last_visit, family_members, total_income primary key: name, date_of_birth cassandra custom type members: occupation, last_visit, family_members, total_income Will the custom data type have any performance benefits while writing or reading when compared to storing the individual data members in terms of Cassandra data types.

Answer 1

Will the custom data type have any performance benefits while writing or reading when compared to storing the individual data members in terms of Cassandra data types.

Not really. Data for user defined types (UDTs) is stored in a single column in the row, and that should be a faster read than multiple individual columns. But whatever performance gain you achieve there will quickly be erased as the data is serialized for the result set. While CQL will allow you to read individual fields of the UDT if you desire, Cassandra still has to read all contents of that column regardless.

It is important to note that user defined types are not about improving performance. They're about offering the flexibility to achieve small amounts of denormalization.

And just a suggestion, but perhaps it makes more sense to have members as a collection, with each item containing data for each family member?