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https://issues.apache.org/jira/browse/IGNITE-23776?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mirza Aliev reassigned IGNITE-23776:
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Assignee: Mirza Aliev (was: Kirill Gusakov)
> Any time rebalance is scheduled pendingChangeTriggerKey must be updated
> ------------------------------------------------------------------------
>
> Key: IGNITE-23776
> URL: https://issues.apache.org/jira/browse/IGNITE-23776
> Project: Ignite
> Issue Type: Improvement
> Reporter: Mirza Aliev
> Assignee: Mirza Aliev
> Priority: Major
> Labels: ignite-3
>
> h3. Motivation
> When an event that triggers rebalancing is processed, we need to ensure that
> this process is completed. We could use {{pendingChangeTriggerKey}} and track
> when it is changed, but there are cases when updating of this key is skipped,
> for example if the assignments already match.
> We need to update {{pendingChangeTriggerKey}} with more up to date value any
> time we try to process new rebalance event.
> h3. Implementation notes.
> There are several places where we change {{pendingChangeTriggerKey}}:
> {{disaster.GroupUpdateRequest#prepareMsInvokeClosure}},
> {{RebalanceUtil#updatePendingAssignmentsKeys}} and
> {{RebalanceUtilEx#handleReduceChanged}}
> For all cases condition for invoke must be improved so we do not skip
> {{pendingChangeTriggerKey}} update if we have the same value of the
> assignments.
> Note, that if we do not pass the general condition of
> {{pendingChangeTriggerKey}}
> {noformat}
> value(changeTriggerKey) < revision
> {noformat}
> we must not update this key with stale value.
> For example, improved condition for
> {{RebalanceUtil#updatePendingAssignmentsKeys}} could look like this:
> {noformat}
> // if empty(partition.change.trigger.revision) ||
> partition.change.trigger.revision < event.revision:
> // if empty(partition.assignments.pending)
> // && ((isNewAssignments &&
> empty(partition.assignments.stable))
> // || (partition.assignments.stable !=
> calcPartAssignments() && !empty(partition.assignments.stable))):
> // partition.assignments.pending = calcPartAssignments()
> // partition.change.trigger.revision = event.revision
> // else:
> // if partition.assignments.pending != calcPartAssignments
> && !empty(partition.assignments.pending)
> // partition.assignments.planned =
> calcPartAssignments()
> // partition.change.trigger.revision = event.revision
> // else if partition.assignments.pending ==
> calcPartAssignments
> // remove(partition.assignments.planned)
> // partition.change.trigger.revision = event.revision
> // message after the metastorage invoke:
> // "Remove planned key because current pending key has
> the same value."
> // else if empty(partition.assignments.pending)
> // remove(partition.assignments.planned)
> // partition.change.trigger.revision = event.revision
> // message after the metastorage invoke:
> // "Remove planned key because pending is empty and
> calculated assignments are equal to current assignments."
> // else:
> // partition.change.trigger.revision = event.revision
> // else:
> // skip
> {noformat}
> Note that all interaction for {{ZoneRebalanceUtil#pendingChangeTriggerKey}}
> also must be improved.
> Also as a refactoring we could change representation of
> {{pendingChangeTriggerKey}} so it could conform the general pattern of
> metastorage keys "prefix + unique" identificator, not vice versa.
> {code:java}
> public static ByteArray pendingChangeTriggerKey(TablePartitionId partId) {
> return new ByteArray("pending.change.trigger" + partId);
> }
> {code}
> h3. Definition of done
> * {{RebalanceUtil.pendingChangeTriggerKey}} is updated with more up to date
> value any time we try to process new rebalance event.
> * The same must be applied to {{ZoneRebalanceUtil.pendingChangeTriggerKey}}
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