Cassandra frozen keyword meaning

database cassandra nosql keyword
Alon picture Alon · Mar 1, 2017 · Viewed 15.7k times · Source

What's the meaning of the frozen keyword in Cassandra?

I'm trying to read this documentation page: Using a user-defined type, but their explanation for the frozen keyword (which they use in their examples) is not clear enough for me:

To support future capabilities, a column definition of a user-defined or tuple type requires the frozen keyword. Cassandra serializes a frozen value having multiple components into a single value. For examples and usage information, see "Using a user-defined type", "Tuple type", and Collection type.

I haven't found any other definition or a clear explanation for that in the net.

Answer

Ashraful Islam picture Ashraful Islam · Mar 1, 2017

In Cassandra if you define UDT or Collection as frozen, you can't update UDT's or collection's individual item, you have to reinsert with full value.

A frozen value serializes multiple components into a single value. Non-frozen types allow updates to individual fields. Cassandra treats the value of a frozen type as a blob. The entire value must be overwritten.

Source : https://docs.datastax.com/en/cql/3.1/cql/cql_reference/collection_type_r.html

@Alon : "Long story short: frozen = immutable"

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