[IGNITE-19532] Introduce happends before relation between local meta storage safe time publication and completion of corresponding meta storage listners

• Type: Improvement
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 3.0
• Labels: ignite-3
• Epic Link: Metastorage Compaction
• Assignee: Semyon Danilov
• Reporter: Alexander Lapin
• Created: 19/May/23 15:23
• Updated: 04/Sep/24 16:10
• Resolved: 25/May/23 08:47

Description

Motivation

Let's assume that we have a component named LeaseTracker that locally stores leases in a map though meta storage updates

public class LeaseTracker implements PlacementDriver {
/** Leases cache. */
private final Map<ReplicationGroupId, Lease> leases; 
...

    private class UpdateListener implements WatchListener {
        @Override
        public CompletableFuture<Void> onUpdate(WatchEvent event) {
            for (EntryEvent entry : event.entryEvents()) {
                     ...
                    Lease lease = fromBytes(msEntry.value());
                    leases.put(grpId, lease);
                    ...
            return completedFuture(null);
        }
    }
...

and we want to await lease in a meta storage safe time bounded way.

public CompletableFuture<LeaseMeta> getPrimaryReplica(ReplicationGroupId replicationGroupId, HybridTimestamp timestamp) {
...

        return msManager.clusterTime().waitFor(timestamp).thenApply(() -> {
                    ...
                    Lease lease0 = leases.get(replicationGroupId);

                    if (lease.getExpirationTime().after(timestamp)) {
                        return lease0;
                    } else {
                        return null;
                    }
                    ...
       }
} 

Currently that won't work properly

because 

msManager.clusterTime().waitFor(timestamp) 

will be completed before local leases will be populated with data through meta storage events.

Thus it'll be nice to complete clusterTime().waitFor(timestamp) futute (and generally speaking publish safe time) after all corresponding ms listeners are completed.

Issue Links

• blocks: IGNITE-18856 Switch primary replica calls from Raft leader to primary replica
• fixes: IGNITE-19271 Persist revision-safeTime mapping in meta-storage
• links to: GitHub Pull Request #2098