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https://issues.apache.org/jira/browse/IGNITE-22759?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Roman Puchkovskiy updated IGNITE-22759:
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Reviewer: Alexander Lapin
> Do not do partition SafeTime sync if previous attempt is not finished
> ---------------------------------------------------------------------
>
> Key: IGNITE-22759
> URL: https://issues.apache.org/jira/browse/IGNITE-22759
> Project: Ignite
> Issue Type: Improvement
> Reporter: Roman Puchkovskiy
> Assignee: Roman Puchkovskiy
> Priority: Major
> Labels: ignite-3
> Time Spent: 3h 40m
> Remaining Estimate: 0h
>
> There is a scheduled task that, periodically, does 'partition SafeTime sync'
> on each primary replicas living on the node. For each such a replica, we do
> the following:
> # Take current time from the node clock ('now')
> # Wait till the Metastorage SafeTime reaches 'now'
> # Make sure the replica is still primary
> # Execute the partition SafeTime sync logic
> Step 2 is implemented by installing a future to a
> PendingComparableValuesTracker representing the Metastorage SafeTime. If, for
> some reason, Metastorage SafeTime lags behind the node clock, a few (or many)
> futures might be installed at the same time for the same partition. When
> there are many partitions, this leads to huge number of futures, most of
> which are useless (just one [the most recent] of them makes sense for each
> partition). This increases the amount of garbage. If the node is already
> struggling to chew the load, this will finish the node off as it will
> increase the GC pressure drastically. The node will choke itself to
> OutOfMemory situation.
> It is suggested to only execute steps 1-4 if previous future has already
> finished. We might lose one partition SafeTime update, but in a situation
> when the node is already struggling (as Metastorage SafeTime lags) this will
> probably not be noticed.
> {*}Update{*}: this approach was critisized, another one is tried
> https://issues.apache.org/jira/browse/IGNITE-22759?focusedCommentId=17895965&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-17895965
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