ivandika3 opened a new pull request, #9796: URL: https://github.com/apache/ozone/pull/9796
## What changes were proposed in this pull request? Currently, if OM follower read is enabled, all OM followers will serve read requests even if the client does not enable the follower read. For read-only client, this might be unexpected since they expect the OM follower to throw OMNotLeaderException. We can support some kind of OM request metadata to indicate to the OM whether the client enables the follower read or not. The implementation introduces `ReadConsistencyHint` field in `OMRequest` which allows client to hint to the OM about what the read consistency the client wants. However, for compatibility reasons, the client `ReadConsistencyHint` is only supported by OM in a best-effort basis. For example, if the new client sends the hint to old OM or OM that disables linearizable read, the OM can choose not to respect the read consistency. Currently, client can configure the default leader and follower read consistency which applies to corresponding requests. However, the long term idea is to allow client to specifies per-request consistency requirements. For example, for S3 we can use custom header (e.g. "x-ozone-read-consistency") to pick the desired consistency. The idea of client-defined consistency level is inspired by other systems - RQLite: https://rqlite.io/docs/api/read-consistency/ - Consul: https://developer.hashicorp.com/consul/api-docs/features/consistency ## What is the link to the Apache JIRA https://issues.apache.org/jira/browse/HDDS-14509 ## How was this patch tested? IT. Clean CI run: https://github.com/ivandika3/ozone/actions/runs/22216665699 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
