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https://issues.apache.org/jira/browse/IGNITE-22467?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17856738#comment-17856738
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Vladislav Pyatkov commented on IGNITE-22467:
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I reviewd the patch and it agrees with my thoughts. But just be aware, a
primary replica might be not a part of assignments. It can happen after
rebalance where we intentanaly hold a primary until lease is expired.
> PlacementDriver should have a method to return an assignments for a specified
> partition
> ---------------------------------------------------------------------------------------
>
> Key: IGNITE-22467
> URL: https://issues.apache.org/jira/browse/IGNITE-22467
> Project: Ignite
> Issue Type: Improvement
> Reporter: Alexander Lapin
> Assignee: Alexander Lapin
> Priority: Major
> Labels: ignite-3
> Time Spent: 10m
> Remaining Estimate: 0h
>
> h3. Motivation
> In order to implement read from backup logic it's required to provide an
> ability to retrieve assignments at best-effort manner.
> h3. Definition of Done
> Following method should be added to the PlacementDriver
> {code:java}
> /**
> * Returns the future with either newest available tokenized assignments for
> the specified replication group id or {@code null} if
> * there are no such assignments. The future will be completed after
> clusterTime (meta storage safe time) will become greater or equal
> * to the clusterTimeToAwait parameter.
> *
> * @param replicationGroupId Replication group Id.
> * @param clusterTimeToAwait Cluster time to await.
> * @return Tokenized assignments.
> */
> CompletableFuture<TokenizedAssignments> getAssignments(ReplicationGroupId
> replicationGroupId, HybridTimestamp clusterTimeToAwait); {code}
> TokenizedAssignments is a common set of nodes along with associated token
> that allows to easely understand whether assignments were changed or not.
> {code:java}
> /**
> * Set of nodes along with associated token that is guaranteed to be changed
> if the set was changed.
> */
> public interface TokenizedAssignments extends Serializable {
> /** Returns a set of nodes, represented by this assignments instance. */
> Set<Assignment> nodes();
> /** Returns a token associated with given assignments that is guaranteed
> to be changed if assignments were changed. */
> long token();
> } {code}
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