zpinto commented on code in PR #2772:
URL: https://github.com/apache/helix/pull/2772#discussion_r1548991400
##########
helix-core/src/main/java/org/apache/helix/controller/stages/BestPossibleStateCalcStage.java:
##########
@@ -161,49 +162,47 @@ private void
addSwapInInstancesToBestPossibleState(Map<String, Resource> resourc
return;
}
- // If the corresponding swap-in instance is not enabled,
assign replicas with
- // initial state.
- if (!enabledSwapInInstances.contains(
- swapOutToSwapInInstancePairs.get(swapOutInstance))) {
-
stateMap.put(swapOutToSwapInInstancePairs.get(swapOutInstance),
- stateModelDef.getInitialState());
- return;
- }
-
- // If the swap-in node is live and enabled, do assignment with
the following logic:
- // 1. If the swap-out instance's replica is a secondTopState,
set the swap-in instance's replica
- // to the same secondTopState.
- // 2. If the swap-out instance's replica is any other state
and is in the preferenceList,
- // set the swap-in instance's replica to the topState if the
StateModel allows another to be added.
- // If not, set the swap-in instance's replica to the
secondTopState.
- // We can make this assumption because if there is assignment
to the swapOutInstance, it must be either
- // a topState or a secondTopState.
- if (stateMap.containsKey(swapOutInstance) &&
stateModelDef.getSecondTopStates()
- .contains(stateMap.get(swapOutInstance))) {
- // If the swap-out instance's replica is a secondTopState,
set the swap-in instance's replica
- // to the same secondTopState.
-
stateMap.put(swapOutToSwapInInstancePairs.get(swapOutInstance),
- stateMap.get(swapOutInstance));
- } else {
- // If the swap-out instance's replica is any other state in
the stateMap or not present in the
- // stateMap, set the swap-in instance's replica to the
topState if the StateModel allows another
- // to be added. If not, set the swap-in to the
secondTopState.
- String topStateCount =
-
stateModelDef.getNumInstancesPerState(stateModelDef.getTopState());
- if (topStateCount.equals(
-
StateModelDefinition.STATE_REPLICA_COUNT_ALL_CANDIDATE_NODES)
- || topStateCount.equals(
- StateModelDefinition.STATE_REPLICA_COUNT_ALL_REPLICAS)) {
- // If the StateModel allows for another replica with the
topState to be added,
- // set the swap-in instance's replica to the topState.
-
stateMap.put(swapOutToSwapInInstancePairs.get(swapOutInstance),
- stateModelDef.getTopState());
+ // If the swap-in node is live, do assignment with the
following logic:
+ // 1. If the swap-out instance's replica is in the stateMap:
+ // - if the swap-out instance's replica is a topState, set the
swap-in instance's replica to the topState.
+ // if another is allowed to be added, otherwise set the
swap-in instance's replica to a secondTopState.
+ // - if the swap-out instance's replica is not a topState or
ERROR, set the swap-in instance's replica to the same state.
+ // - if the swap-out instance's replica is ERROR, set the
swap-in instance's replica to the initialState.
+ // 2. If the swap-out instance's replica is not in the
stateMap, set the swap-in instance's replica to the initialState.
+ // This happens when the swap-out node is offline.
+ if (stateMap.containsKey(swapOutInstance)) {
+ if
(stateMap.get(swapOutInstance).equals(stateModelDef.getTopState())
+ ||
stateMap.get(swapOutInstance).equals(HelixDefinedState.ERROR.name())) {
+ // If the swap-out instance's replica is a topState, set
the swap-in instance's replica
+ // to the topState if the StateModel allows another to be
added. If not, set the swap-in
+ // to the secondTopState.
+ String topStateCount =
+
stateModelDef.getNumInstancesPerState(stateModelDef.getTopState());
+ if (topStateCount.equals(
+
StateModelDefinition.STATE_REPLICA_COUNT_ALL_CANDIDATE_NODES)
+ || topStateCount.equals(
+
StateModelDefinition.STATE_REPLICA_COUNT_ALL_REPLICAS)) {
+ // If the StateModel allows for another replica with the
topState to be added,
+ // set the swap-in instance's replica to the topState.
+
stateMap.put(swapOutToSwapInInstancePairs.get(swapOutInstance),
+ stateModelDef.getTopState());
+ } else {
+ // If StateModel does not allow another topState replica
to be
+ // added, set the swap-in instance's replica to the
secondTopState.
+
stateMap.put(swapOutToSwapInInstancePairs.get(swapOutInstance),
+
stateModelDef.getSecondTopStates().iterator().next());
+ }
} else {
- // If StateModel does not allow another topState replica
to be
- // added, set the swap-in instance's replica to the
secondTopState.
+ // If the swap-out instance's replica is not a topState or
ERROR, set the swap-in instance's replica
+ // to the same state
stateMap.put(swapOutToSwapInInstancePairs.get(swapOutInstance),
- stateModelDef.getSecondTopStates().iterator().next());
+ stateMap.get(swapOutInstance));
}
+ } else {
+ // If the swap-out instance's replica is not in the
stateMap, set the swap-in instance's replica
+ // to the initialState. This happens when the swap-out node
is offline.
+
stateMap.put(swapOutToSwapInInstancePairs.get(swapOutInstance),
+ stateModelDef.getInitialState());
}
});
});
Review Comment:
I have separated assignment and and state selection into two steps to make
it more debuggable.
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