jackjlli commented on code in PR #11953: URL: https://github.com/apache/pinot/pull/11953#discussion_r1396731814
########## pinot-controller/src/main/java/org/apache/pinot/controller/helix/core/assignment/instance/InstanceReplicaGroupPartitionSelector.java: ########## @@ -73,16 +76,65 @@ public void selectInstances(Map<Integer, List<InstanceConfig>> poolToInstanceCon Map<Integer, List<Integer>> poolToReplicaGroupIdsMap = new TreeMap<>(); Map<Integer, Integer> replicaGroupIdToPoolMap = new TreeMap<>(); Map<Integer, Set<String>> poolToCandidateInstancesMap = new TreeMap<>(); - for (int replicaId = 0; replicaId < numReplicaGroups; replicaId++) { - // Pick one pool for each replica-group based on the table name hash - int pool = pools.get((tableNameHash + replicaId) % numPools); - poolToReplicaGroupIdsMap.computeIfAbsent(pool, k -> new ArrayList<>()).add(replicaId); - replicaGroupIdToPoolMap.put(replicaId, pool); + Map<String, Integer> instanceToPoolMap = new HashMap<>(); + for (Map.Entry<Integer, List<InstanceConfig>> entry : poolToInstanceConfigsMap.entrySet()) { + Integer pool = entry.getKey(); + List<InstanceConfig> instanceConfigsInPool = entry.getValue(); + Set<String> candidateInstances = poolToCandidateInstancesMap.computeIfAbsent(pool, k -> new LinkedHashSet<>()); + for (InstanceConfig instanceConfig : instanceConfigsInPool) { + String instanceName = instanceConfig.getInstanceName(); + candidateInstances.add(instanceName); + instanceToPoolMap.put(instanceName, pool); + } + } - Set<String> candidateInstances = - poolToCandidateInstancesMap.computeIfAbsent(pool, k -> new LinkedHashSet<>()); - List<InstanceConfig> instanceConfigsInPool = poolToInstanceConfigsMap.get(pool); - instanceConfigsInPool.forEach(k -> candidateInstances.add(k.getInstanceName())); + if (_minimizeDataMovement && _existingInstancePartitions != null) { + // Keep the same pool for the replica group if it's already been used for the table. + int existingNumPartitions = _existingInstancePartitions.getNumPartitions(); + int existingNumReplicaGroups = _existingInstancePartitions.getNumReplicaGroups(); + int numCommonReplicaGroups = Math.min(numReplicaGroups, existingNumReplicaGroups); Review Comment: The reason of checking the common replica groups is that it's not always the case that numReplicaGroups gets incremented. If the number of replica groups is reduced, we don't actually care what was used for the stale RG which is no longer needed. That's why the common one is used here. The scenarios you mentioned can be covered by using the min heap in Line 112, which is to gather the pool number as well as the number of times to be chosen. The one with the least frequent usage would always be chosen to assign to a RG. Keep in mind that 1 RG can only have 1 pool (RG -> pool), while 1 pool may have more than 1 RG (pool -> [RG]). -- 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: commits-unsubscr...@pinot.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For additional commands, e-mail: commits-h...@pinot.apache.org