Cassandra 2.1.0 - Batch inserts into multiple tables

[Dave Decicco]

Good afternoon,

I'm trying to figure out the best way to provide transactional like insertions into multiple tables in Cassandra.

I have a scenario where I need 5 inserts to occur into 5 different tables, with different partition keys, and would like all statements to be inserted or none of the statements inserted.

I have read that the batch statement can be used but the examples I've seen insert to the same table with the same partition key for all the insertions.

Can I use a batch statement to perform 5 inserts into 5 different tables even if the partition keys of those tables differ?  I have also seen some examples online where the session.ExecuteAsync() is used but I don't believe I can use that as I'm using .NET Framework 4.0.

Is it safe to use the batch statement in this scenario?  I realize there will be a performance hit if the partition keys differ but I'd like to make sure that all 5 statements are executed.

I'm looking for the some best practices recommendations when the partition keys of the tables differ.

Thank you for your time,

Dave Decicco

[Jorge Bay Gondra]

Hi Dave,

For the scenario you describe, you should use batch statements.

Executing a logged batch is an atomic operation: no risk of partially applied batches. Batches can be used for different partitions and column families.

In the project Readme you have an example using different tables:

//Prepare the statements involved in a profile update once
var profileStmt = session.Prepare("UPDATE user_profiles SET email=? WHERE key=?");
var userTrackStmt = session.Prepare("INSERT INTO user_track (key, text, date) VALUES (?, ?, ?)");
//...you should reuse the prepared statements
//Bind the parameters and add the statement to the batch batch
var batch = new BatchStatement()
  .Add(profileStmt.Bind(emailAddress, "hendrix"))
  .Add(userTrackStmt.Bind("hendrix", "You changed your email", DateTime.Now));
//Execute the batch
session.Execute(batch);

Jorge

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[Dave Decicco]

Thank you for the quick response Jorge.

I will take a look.  I have read that there is a 30% performance hit when logged batches are performed.

Is this correct?  or does it depend on the number of different partitions in the batch statements?