Presto Cassandra Connector : number of connections

2
votes

I am looking into increasing the number of connections Presto makes to ScyllaDB. I am using Presto's Cassandra connector to connect to ScyllaDB. I don't see any property in the documentation that can be used to increase the number of connections. https://prestodb.io/docs/current/connector/cassandra.html

This is my scylladb.properties file

connector.name=cassandra
cassandra.contact-points=scylla1,scylla2,scylla3,scylla4
cassandra.client.read-timeout=3600000ms
cassandra.split-size=1024
cassandra.fetch-size=5000
cassandra.load-policy.token-aware.shuffle-replicas=true
cassandra.load-policy.use-token-aware=true

What is the default number of connections that Presto makes to cassandra/scylladb and how can I set this property? Thanks

1
prestoscylla

1 Answers

5
votes

Using the same logic as we do for Spark, reducing the cassandra.split-size to a lower number should make you benefit from the following:

  • Coordination and data fetching is distributed among several coordinators
  • Higher concurrency of requests, which translates to a higher number of connections between the Presto node/s and Scylla nodes

See how cassandra.split-size=1 behaves and if needed raise to 10, 50, 100