[IGNITE-23025] Java thin 3.0: Use all replicas for partition awareness

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Fix Version/s: 3.1
• Component/s: thin client
• Labels: ignite-3
• Epic Link: AI3 Performance
• Assignee: Pavel Tupitsyn
• Reporter: Pavel Tupitsyn
• Created: 19/Aug/24 14:36
• Updated: 04/Sep/24 16:29

Description

Currently, client uses primary replicas for partition awareness:

• Get primary replica per partition from server (Map<Partition, Replica>)
• Compute target replica from key
• If a direct connection exists to that replica, use it. Otherwise, use any other connection.

We can improve performance for certain requests (RO transactions) by using non-primary replicas as well:

• Get all replicas per partition from server (first = primary) (Map<Partition, List<Replica>>)
• Compute target partition from key
• Iterate over the list of replicas in original order to find an active direct connection

In other words, "use primary replica if possible, otherwise use non-primary replica, otherwise use any connection".