CODEWITHSUNDEEP
pythoncassandraprepared-statementdatastax
causa prima
causa prima

Reputation: 1712

Receive already prepared statement from Cassandra

I'm not completely shure I get the concepts of prepared statements right, but according to the python driver docs a prepared statement is "A statement that has been prepared against at least one Cassandra node". To me that reads that somewhere in the cluster there is information on what queries have already been prepared.The documentation furthermore states that "A PreparedStatement should be prepared only once. Re-preparing a statement may affect performance (as the operation requires a network roundtrip).".

If I get the concept right it would be beneficial to receive already prepared statements from the cluster instead of repeatedly regenerating them(1). Is there a way to do so? And if yes, how do I only receive statements I am interested in?

(1)I'm not talking about the scope of one instance of a programm, but multiple instances without shared memory executing the same queries.

Upvotes: 1

Views: 311

Answers (1)

Adam Holmberg
Adam Holmberg

Reputation: 7365

You are correct: each node in the cluster caches prepared statements. However, there is no mechanism for obtaining already-prepared statements in the client. There are a number of reasons for this that I won't expound upon here.

Your application your prepare a statement once and keep it around for the lifetime of the cluster/session. The drivers handle things like preparing the statement on all nodes, and re-preparing on nodes that lose them due to cache eviction or restarts.

Upvotes: 1

Related Questions