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https://issues.apache.org/jira/browse/IGNITE-23413?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17901208#comment-17901208
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Ivan Bessonov commented on IGNITE-23413:
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Current progress status:
* proposed algorithm is more or less intact
* I implemented it for both "current" code and "zone collocation" code, with 2
versions of tests
* code used to be in a "cleanup" phase
* I noticed that in some circumstances my code could hold old catalog
indefinitely
* it has been decided to account for {{pendingChangeTriggerKey}} values in
order to avoid these situations. This is what I'm adding right now
* the _"they would need to retry the read on oldest known revision"_ part will
have its own Jira, I'll create it soon
Why does it take so long - a lot of side activities and my inability to come up
with a proper solution. I keep re-writing it, finding more and more cases where
my code is broken.
> Catalog compaction. Component to determine minimum catalog version required
> by rebalance.
> -----------------------------------------------------------------------------------------
>
> Key: IGNITE-23413
> URL: https://issues.apache.org/jira/browse/IGNITE-23413
> Project: Ignite
> Issue Type: Improvement
> Reporter: Pavel Pereslegin
> Assignee: Ivan Bessonov
> Priority: Major
> Labels: ignite-3
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Each rebalance procedure uses specific catalog version, it "holds" the
> timestamp corresponding to the latest (at the moment of rebalancing start)
> version of the catalog
> To be able safely perform catalog compaction, we need to design and implement
> a component that can determine the minimum version required for active
> rebalances (to avoid deleting this version during compaction).
> {code:java}
> interface RebalanceMinimumRequiredTimeProvider {
> /**
> * Returns the minimum time required for rebalance,
> * or current timestamp if there are no active
> * rebalances and there is a guarantee that all rebalances
> * launched in the future will use catalog version
> * corresponding to the current time or greater.
> */
> long minimumRequiredTime();
> }
> {code}
> The component can be either global or local (whichever is easier to
> implement). This means that the compaction procedure can call the component
> on all nodes in the cluster and calculate the minimum.
> The component must be able to track rebalances that may be triggered during
> "replay" of the metastorage raft log.
> The component should return only monotonically increasing values.
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