csudharsanan commented on code in PR #3043:
URL: https://github.com/apache/helix/pull/3043#discussion_r2167427562
##########
helix-core/src/main/java/org/apache/helix/controller/stages/MessageGenerationPhase.java:
##########
@@ -250,17 +262,40 @@ private void generateMessage(final Resource resource,
final BaseControllerDataPr
pendingMessage, manager, resource, partition,
sessionIdMap, instanceName,
stateModelDef, cancellationMessage, isCancellationEnabled);
} else {
+ // Set currentActiveReplicaNumber to provide metadata for
potential message prioritization by
+ // participant.
+ // Assign the current active replica count to all qualifying
upward transitions for this
+ // partition.
+ // This ensures consistent prioritization metadata across
concurrent state transitions.
+ int currentActiveReplicaNumber = -1; // -1 indicates no
prioritization metadata, for eg:
+ // Downward ST messages get a -1.
+
+ /*
+ Assign currentActiveReplicaNumber for qualifying upward state
transitions.
+ Criteria for assignment:
+ - Must be an upward state transition according to state model
+ - Current state must not be considered active (according to
state model type)
+ - Target state must be considered active (according to state
model type)
+ */
+ if (stateModelDef.isUpwardStateTransition(currentState, nextState)
+ && !isStateActive(currentState, stateModelDef)
Review Comment:
The rationale here is that state transitions (STs) from secondary top state
to top state are already prioritized by recovery rebalance, so this metadata
becomes redundant for those transitions.
That said, I don't see any issues with adding this metadata for the current
transition logic. We're simply indicating how many replicas are active at any
given point in time. However, I'm concerned that surfacing this metadata for
state transitions that aren't part of load balancing could create confusion.
Would it make sense to scope this metadata only to load balance-related
transitions to maintain clarity? I can update the comments in this case to add
clarity.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: reviews-unsubscr...@helix.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@helix.apache.org
For additional commands, e-mail: reviews-h...@helix.apache.org
