jackjlli commented on code in PR #8483: URL: https://github.com/apache/pinot/pull/8483#discussion_r854730114
########## pinot-controller/src/main/java/org/apache/pinot/controller/helix/core/assignment/instance/InstanceReplicaGroupPartitionSelector.java: ########## @@ -140,25 +132,118 @@ public void selectInstances(Map<Integer, List<InstanceConfig>> poolToInstanceCon LOGGER.info("Selecting {} partitions, {} instances per partition within a replica-group for table: {}", numPartitions, numInstancesPerPartition, _tableNameWithType); - // Assign consecutive instances within a replica-group to each partition. - // E.g. (within a replica-group, 5 instances, 3 partitions, 3 instances per partition) - // [i0, i1, i2, i3, i4] - // p0 p0 p0 p1 p1 - // p1 p2 p2 p2 - for (int replicaGroupId = 0; replicaGroupId < numReplicaGroups; replicaGroupId++) { - int instanceIdInReplicaGroup = 0; - for (int partitionId = 0; partitionId < numPartitions; partitionId++) { - List<String> instancesInPartition = new ArrayList<>(numInstancesPerPartition); - for (int instanceIdInPartition = 0; instanceIdInPartition < numInstancesPerPartition; - instanceIdInPartition++) { - instancesInPartition.add(replicaGroupIdToInstancesMap[replicaGroupId][instanceIdInReplicaGroup]); - instanceIdInReplicaGroup = (instanceIdInReplicaGroup + 1) % numInstancesPerReplicaGroup; + if (_replicaGroupPartitionConfig.isMinimizeDataMovement() && _existingInstancePartitions != null) { + // Minimize data movement. + int existingNumPartitions = _existingInstancePartitions.getNumPartitions(); + int existingNumReplicaGroups = _existingInstancePartitions.getNumReplicaGroups(); + + Map<Integer, Set<String>> poolToCandidateInstancesMap = new TreeMap<>(); + Map<Integer, Set<String>> replicaGroupIdToInstancesMap = new HashMap<>(); + for (int replicaGroupId = 0; replicaGroupId < existingNumReplicaGroups; replicaGroupId++) { + Integer pool = replicaGroupIdToPoolMap.get(replicaGroupId); + if (pool == null) { + // Skip the replica group if it's no longer needed. + continue; + } + Set<String> candidateInstances = + poolToCandidateInstancesMap.computeIfAbsent(pool, k -> new LinkedHashSet<>()); + List<InstanceConfig> instanceConfigsInPool = poolToInstanceConfigsMap.get(pool); + instanceConfigsInPool.forEach(k -> candidateInstances.add(k.getInstanceName())); + + for (int partitionId = 0; partitionId < existingNumPartitions; partitionId++) { + List<String> existingInstances = _existingInstancePartitions.getInstances(partitionId, replicaGroupId); + replicaGroupIdToInstancesMap.computeIfAbsent(replicaGroupId, k -> new HashSet<>()) + .addAll(existingInstances); + } + } + + for (int replicaGroupId = 0; replicaGroupId < existingNumReplicaGroups; replicaGroupId++) { Review Comment: The 1st loop is to find out the existing RGs and their instances. The 2nd loop is to filter out those instances which are already used in other RGs. In order to filter all the instances that belong to other RGs, the 1st loop is needed. That's why we need 2 loops separately. -- 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