@spring-projects-issues

lmcdasi opened DATACASS-751 and commented

In the data stax 4.5 manual it is indicated that creating session/keyspace (https://docs.datastax.com/en/developer/java-driver/4.5/manual/core/) is an anti-pattern:

"// Anti-pattern: creating two sessions doubles the number of TCP connections opened by the driver"

You have a solution that uses the AbstractRoutingSessionFactory that just implement that anti-pattern.

But the data stax driver provides actually two different solutions to avoid having that antipattern.

1. use the setKeypace when creating a Statement - but this is OK only if the version supported if > V4. Which would not be available for all.
2. use the built-in QueryBuilder queries that have the keyspace as a parameter. Example: looking at the QueryBuilder.insertInto - it could be changed to use the keyspace since the insertInto signature allows for a a keyspace & a table name. The Statement builder will then build the query by having the keyspace + "." + tablename.

The impacted classes are CassandraTemplate & StatementFactory. I attach example code of above where I test the insertTo successfully.

At the same time, while the framework allows me in CassandraConfig to specify a bean to create a cassandraTemplate that can be different than the default CassandraTemplate it does not allow me to re-use the existing framework classes in order to implement my self a template & statement factory where I can specify the keyspace without being forced to copy them out of the framework.

The keyspace can be kept in a ThreadLocal - using the same principle used for AbstractRoutingSessionFactory .

If we cannot have a template as such in the framework, can we at least have the possibility to implement a CassandraTemplace without being forced to copy a lot of code in order to access the existing framework classes ? The template requires quite a few classes that are private.

This assumes that the keyspace schema are the same.

Thank you

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Affects: 3.0 RC1 (Neumann)

Attachments:

• DalAdminTemplate.java (6.05 kB)
• DalStatementFactory.java (39.27 kB)
• DalTemplate.java (39.87 kB)

1 votes, 4 watchers