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https://issues.apache.org/jira/browse/CASSANDRA-13569?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16066564#comment-16066564
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Stefan Podkowinski commented on CASSANDRA-13569:
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The mentioned future for the delayed schema migration will only represent the
status of the scheduled execution, but not if the schema pull itself was
successful. A completed future simply indicates that the delayed execution took
place. Afterwards we're free to try the next schema pull if we have to.
The intention of this ticket is not to redesign any retry/timeout semantics or
to reimplement the schema exchange protocol. This would need more careful
thinking and should possibly done in context of CASSANDRA-10699.
> Schedule schema pulls just once per endpoint
> --------------------------------------------
>
> Key: CASSANDRA-13569
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13569
> Project: Cassandra
> Issue Type: Improvement
> Components: Distributed Metadata
> Reporter: Stefan Podkowinski
> Assignee: Stefan Podkowinski
> Fix For: 3.0.x, 3.11.x, 4.x
>
>
> Schema mismatches detected through gossip will get resolved by calling
> {{MigrationManager.maybeScheduleSchemaPull}}. This method may decide to
> schedule execution of {{MigrationTask}}, but only after using a
> {{MIGRATION_DELAY_IN_MS = 60000}} delay (for reasons unclear to me).
> Meanwhile, as long as the migration task hasn't been executed, we'll continue
> to have schema mismatches reported by gossip and will have corresponding
> {{maybeScheduleSchemaPull}} calls, which will schedule further tasks with the
> mentioned delay. Some local testing shows that dozens of tasks for the same
> endpoint will eventually be executed and causing the same, stormy behavior
> for this very endpoints.
> My proposal would be to simply not schedule new tasks for the same endpoint,
> in case we still have pending tasks waiting for execution after
> {{MIGRATION_DELAY_IN_MS}}.
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