CODEWITHSUNDEEP
cassandracassandra-3.0
Vishal Sharma
Vishal Sharma

Reputation: 1750

Ensuring synchronous read-write in Cassandra

I have a Cassandra Cluster which will be used by multiple clients. I have a table(let's call it 'Counter')in my keyspace which I'm using to store the count of the number of entries in other tables.

Whenever a new entry has to be inserted in some table, first the 'Counter' table will be queried to find out the number of entries already inside that table and then it will be incremented after a new row has been added to the table.

Since, there are multiple clients, how can I ensure that 2 clients simultaneously don't try to read/write on the 'Counter' table.

My Cluster is on 3.11.2.

Upvotes: 0

Views: 226

Answers (1)

Chris Lohfink
Chris Lohfink

Reputation: 16420

You can use counters and increment on a new entry: https://docs.datastax.com/en/cql/3.3/cql/cql_using/useCounters.html

Or light weight transactions. If the value is applied you know no one else read/written in that time - if they have you just retry. https://docs.datastax.com/en/cassandra/3.0/cassandra/dml/dmlLtwtTransactions.html

Might be good to write some kind of job that can be run that scans and counts the entries and compares to current value. Inconsistencies between your 2 tables are possible if a node crashes in-between the increment and the new entry inserted.

Upvotes: 3

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