ID | IEP-110112 |
Author | |
Sponsor | |
Created | 25.10.2023 |
Status | |
Motivation
The thin client invokes the service grid on a random server node. A service may not be deployed on each node. If node misses the invoked service, the invocation request is redirected to a proper node. Such redirection costs.
Description
There already is a similar feature - Partition Awareness. When enabled, the client calls exactly the primary node to update cache by key.
To achieve Service Awareness we should:
1) Bring a new feature to the thin client protocol.
2) Require the partition awareness and activate with the Partition Awareness flag enabled. It raises proper cluster connections.
3) Obtain service topology with a dedicated request by the client and provide it to the service proxies.
4) Initiate the topology update with: first service invocation, cluster topology change, some timeout (only if service is invoked).
New protocol feature
Minimal client protocol version | 1.7.0 |
The new protocol feature | SERVICE_TOPOLOGY = 16 |
Service topology request
One new client operation is required:
Name | Code |
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OP_SERVICE_GET_TOPOLOGY | 7003 |
OP_SERVICE_GET_TOPOLOGY message format
Request |
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String | Service name |
Response |
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int | Number of the following nodes UUIDs |
UUID * count | UUID of node with at least one service instance |
Risks and Assumptions
- Some delay of the topology obtaining. The invocation redirects are still possible when service migrates.
- No sign of service cancel/deploy on the client side. We have to update by a timeout too.
- The topology is probably kept by client while it exists even if the service proxy is not in use any more or if service was canceled.
Discussion Links
https://lists.apache.org/thread/vd0wnwxrg89245kv1nzolfb82j1l7z0t
Tickets
Java Thin Client implementation | Jira |
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server | ASF JIRA |
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serverId | 5aa69414-a9e9-3523-82ec-879b028fb15b |
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key | IGNITE-20656 |
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