CODEWITHSUNDEEP
cassandranosqlignitekey-value-store
user2992672
user2992672

Reputation: 408

How to model data using Cassandra and Ignite together?

I'm researching how to model data having both Cassandra and Ignite together. So far the basic recommendation of data modeling in Cassandra (coming from this article) is clear: "model data around your queries". An author gives an example of "user lookup". We want to look up for users by their username or their email and according to him the best approach would be having two tables: 

CREATE TABLE users_by_username (
    username text PRIMARY KEY,
    email text,
    age int
)

CREATE TABLE users_by_email (
    email text PRIMARY KEY,
    username text,
    age int
)

However things get confusing with Ignite on the top of Cassandra. Unfortunately I could not find any helpful examples or answers to the following questions:

  1. Does having multiple tables that store user information mean having Ignite cache for each of these tables?
  2. Does having compound primary key mean introducing new type for each key and use it as Ignite cache key?
  3. Having Ignite means not having direct reads from Cassandra. Does it even make scene to bother modeling data following NoSql best practices? Would it be ok to just have one user table and let Ignite take care of queries by username or email. 
CREATE TABLE users (
    id uuid PRIMARY KEY,
    username text,
    email text,
    age int
)

Upvotes: 0

Views: 60

Answers (1)

alamar
alamar

Reputation: 19313

  1. You should probably have one cache per Cassandra table.

  2. If your original key is compound, so should Ignite key be.

  3. You will need to use secondary indexes in Ignite to query by more than one field, and this means you will have to hold all data in Ignite (which is NOT necessary for pure caching scenario). This means enabling readThrough and writeThrough, doing loadCache and always doing all updates through Ignite. You will have to choose between "Ignite as cache for Cassandra" (stick to Cassandra's data layout, can hold partial data) and "Ignite as DB backed by Cassandra" (you can use layout optimal for Ignite, secondary indexes).

Upvotes: 1

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