somandal commented on code in PR #15617:
URL: https://github.com/apache/pinot/pull/15617#discussion_r2083767580
##########
pinot-controller/src/main/java/org/apache/pinot/controller/helix/core/rebalance/TableRebalancer.java:
##########
@@ -1524,67 +1535,276 @@ private static void handleErrorInstance(String
tableNameWithType, String segment
}
}
+ /**
+ * Uses the default LOGGER
+ */
+ @VisibleForTesting
+ static Map<String, Map<String, String>> getNextAssignment(Map<String,
Map<String, String>> currentAssignment,
+ Map<String, Map<String, String>> targetAssignment, int
minAvailableReplicas, boolean enableStrictReplicaGroup,
+ boolean lowDiskMode, int batchSizePerServer,
Object2IntOpenHashMap<String> segmentPartitionIdMap,
+ PartitionIdFetcher partitionIdFetcher) {
+ return getNextAssignment(currentAssignment, targetAssignment,
minAvailableReplicas, enableStrictReplicaGroup,
+ lowDiskMode, batchSizePerServer, segmentPartitionIdMap,
partitionIdFetcher, LOGGER);
+ }
+
/**
* Returns the next assignment for the table based on the current assignment
and the target assignment with regard to
* the minimum available replicas requirement. For strict replica-group
mode, track the available instances for all
* the segments with the same instances in the next assignment, and ensure
the minimum available replicas requirement
* is met. If adding the assignment for a segment breaks the requirement,
use the current assignment for the segment.
+ * <p>
+ * For strict replica group routing only (where the segment assignment is
not StrictRealtimeSegmentAssignment)
+ * if batching is enabled, the instances assigned for the same partitionId
can be different for different segments.
+ * For strict replica group routing with StrictRealtimeSegmentAssignment on
the other hand, the assignment for a given
+ * partitionId will be the same across all segments. We can treat both cases
similarly by creating a mapping from
+ * partitionId -> unique set of instance assignments -> currentAssignment.
With StrictRealtimeSegmentAssignment,
+ * this map will have a single entry for 'unique set of instance
assignments'.
+ * <p>
+ * TODO: Ideally if strict replica group routing is enabled then
StrictRealtimeSegmentAssignment should be used, but
+ * this is not enforced in the code today. Once enforcement is added,
then the routing side and assignment side
+ * will be equivalent and all segments belonging to a given
partitionId will be assigned to the same set of
+ * instances. Special handling to check each group of assigned
instances can be removed in that case.
*/
- @VisibleForTesting
- static Map<String, Map<String, String>> getNextAssignment(Map<String,
Map<String, String>> currentAssignment,
+ private static Map<String, Map<String, String>>
getNextAssignment(Map<String, Map<String, String>> currentAssignment,
Map<String, Map<String, String>> targetAssignment, int
minAvailableReplicas, boolean enableStrictReplicaGroup,
- boolean lowDiskMode) {
- return enableStrictReplicaGroup ?
getNextStrictReplicaGroupAssignment(currentAssignment, targetAssignment,
- minAvailableReplicas, lowDiskMode)
+ boolean lowDiskMode, int batchSizePerServer,
Object2IntOpenHashMap<String> segmentPartitionIdMap,
+ PartitionIdFetcher partitionIdFetcher, Logger tableRebalanceLogger) {
+ return enableStrictReplicaGroup
+ ? getNextStrictReplicaGroupAssignment(currentAssignment,
targetAssignment, minAvailableReplicas, lowDiskMode,
+ batchSizePerServer, segmentPartitionIdMap, partitionIdFetcher,
tableRebalanceLogger)
: getNextNonStrictReplicaGroupAssignment(currentAssignment,
targetAssignment, minAvailableReplicas,
- lowDiskMode);
+ lowDiskMode, batchSizePerServer);
}
private static Map<String, Map<String, String>>
getNextStrictReplicaGroupAssignment(
Map<String, Map<String, String>> currentAssignment, Map<String,
Map<String, String>> targetAssignment,
- int minAvailableReplicas, boolean lowDiskMode) {
+ int minAvailableReplicas, boolean lowDiskMode, int batchSizePerServer,
+ Object2IntOpenHashMap<String> segmentPartitionIdMap, PartitionIdFetcher
partitionIdFetcher,
+ Logger tableRebalanceLogger) {
Map<String, Map<String, String>> nextAssignment = new TreeMap<>();
Map<String, Integer> numSegmentsToOffloadMap =
getNumSegmentsToOffloadMap(currentAssignment, targetAssignment);
+ Map<Integer, Map<Set<String>, Map<String, Map<String, String>>>>
+ partitionIdToAssignedInstancesToCurrentAssignmentMap;
+ if (batchSizePerServer == RebalanceConfig.DISABLE_BATCH_SIZE_PER_SERVER) {
+ // Don't calculate the partition id to assigned instances to current
assignment mapping if batching is disabled
+ // since we want to update the next assignment based on all partitions
in this case. Use partitionId as 0
+ // and a dummy set for the assigned instances.
+ partitionIdToAssignedInstancesToCurrentAssignmentMap = new TreeMap<>();
+ partitionIdToAssignedInstancesToCurrentAssignmentMap.put(0, new
HashMap<>());
+
partitionIdToAssignedInstancesToCurrentAssignmentMap.get(0).put(Set.of(""),
currentAssignment);
+ } else {
+ partitionIdToAssignedInstancesToCurrentAssignmentMap =
+
getPartitionIdToAssignedInstancesToCurrentAssignmentMap(currentAssignment,
segmentPartitionIdMap,
+ partitionIdFetcher);
+ }
Map<Pair<Set<String>, Set<String>>, Set<String>> assignmentMap = new
HashMap<>();
Map<Set<String>, Set<String>> availableInstancesMap = new HashMap<>();
- for (Map.Entry<String, Map<String, String>> entry :
currentAssignment.entrySet()) {
- String segmentName = entry.getKey();
- Map<String, String> currentInstanceStateMap = entry.getValue();
- Map<String, String> targetInstanceStateMap =
targetAssignment.get(segmentName);
- SingleSegmentAssignment assignment =
- getNextSingleSegmentAssignment(currentInstanceStateMap,
targetInstanceStateMap, minAvailableReplicas,
- lowDiskMode, numSegmentsToOffloadMap, assignmentMap);
- Set<String> assignedInstances = assignment._instanceStateMap.keySet();
- Set<String> availableInstances = assignment._availableInstances;
- availableInstancesMap.compute(assignedInstances, (k,
currentAvailableInstances) -> {
- if (currentAvailableInstances == null) {
- // First segment assigned to these instances, use the new assignment
and update the available instances
- nextAssignment.put(segmentName, assignment._instanceStateMap);
- updateNumSegmentsToOffloadMap(numSegmentsToOffloadMap,
currentInstanceStateMap.keySet(), k);
- return availableInstances;
- } else {
- // There are other segments assigned to the same instances, check
the available instances to see if adding the
- // new assignment can still hold the minimum available replicas
requirement
- availableInstances.retainAll(currentAvailableInstances);
- if (availableInstances.size() >= minAvailableReplicas) {
- // New assignment can be added
+
+ Map<String, Integer> serverToNumSegmentsAddedSoFar = new HashMap<>();
+ for (Map<Set<String>, Map<String, Map<String, String>>>
assignedInstancesToCurrentAssignment
+ : partitionIdToAssignedInstancesToCurrentAssignmentMap.values()) {
+ boolean anyServerExhaustedBatchSize = false;
+ if (batchSizePerServer != RebalanceConfig.DISABLE_BATCH_SIZE_PER_SERVER)
{
+ // Check if the servers of the first assignment for each unique set of
assigned instances has any space left
+ // to move this partition. If so, let's mark the partitions as to be
moved, otherwise we mark the partition
+ // as a whole as not moveable.
+ for (Map<String, Map<String, String>> curAssignment :
assignedInstancesToCurrentAssignment.values()) {
+ Map.Entry<String, Map<String, String>> firstEntry =
curAssignment.entrySet().iterator().next();
+ // All segments should be assigned to the same set of servers so it
is enough to check for whether any server
+ // for one segment is above the limit or not
+ Map<String, String> firstEntryInstanceStateMap =
firstEntry.getValue();
+ SingleSegmentAssignment firstAssignment =
+ getNextSingleSegmentAssignment(firstEntryInstanceStateMap,
targetAssignment.get(firstEntry.getKey()),
+ minAvailableReplicas, lowDiskMode, numSegmentsToOffloadMap,
assignmentMap);
+ Set<String> serversAdded =
getServersAddedInSingleSegmentAssignment(firstEntryInstanceStateMap,
+ firstAssignment._instanceStateMap);
+ for (String server : serversAdded) {
+ if (serverToNumSegmentsAddedSoFar.getOrDefault(server, 0) >=
batchSizePerServer) {
+ anyServerExhaustedBatchSize = true;
+ break;
+ }
+ }
+ if (anyServerExhaustedBatchSize) {
+ break;
+ }
+ }
+ }
+ for (Map<String, Map<String, String>> curAssignment :
assignedInstancesToCurrentAssignment.values()) {
+ getNextAssignmentForPartitionIdStrictReplicaGroup(curAssignment,
targetAssignment, nextAssignment,
+ anyServerExhaustedBatchSize, minAvailableReplicas, lowDiskMode,
numSegmentsToOffloadMap, assignmentMap,
+ availableInstancesMap, serverToNumSegmentsAddedSoFar);
+ }
+ }
+
+ checkIfAnyServersAssignedMoreSegmentsThanBatchSize(batchSizePerServer,
serverToNumSegmentsAddedSoFar,
+ tableRebalanceLogger);
+ return nextAssignment;
+ }
+
+ private static void
getNextAssignmentForPartitionIdStrictReplicaGroup(Map<String, Map<String,
String>> curAssignment,
+ Map<String, Map<String, String>> targetAssignment, Map<String,
Map<String, String>> nextAssignment,
+ boolean anyServerExhaustedBatchSize, int minAvailableReplicas, boolean
lowDiskMode,
+ Map<String, Integer> numSegmentsToOffloadMap, Map<Pair<Set<String>,
Set<String>>, Set<String>> assignmentMap,
+ Map<Set<String>, Set<String>> availableInstancesMap, Map<String,
Integer> serverToNumSegmentsAddedSoFar) {
+ if (anyServerExhaustedBatchSize) {
+ // Exhausted the batch size for at least 1 server, just copy over the
remaining segments as is
+ for (Map.Entry<String, Map<String, String>> entry :
curAssignment.entrySet()) {
+ String segmentName = entry.getKey();
+ Map<String, String> currentInstanceStateMap = entry.getValue();
+ nextAssignment.put(segmentName, currentInstanceStateMap);
+ }
+ } else {
+ // Process all the partitionIds even if segmentsAddedSoFar becomes
larger than batchSizePerServer
+ // Can only do bestEfforts w.r.t. StrictReplicaGroup since a whole
partition must be moved together for
+ // maintaining consistency
+ for (Map.Entry<String, Map<String, String>> entry :
curAssignment.entrySet()) {
Review Comment:
I apply it for the full partitionId irrespective of whether there is a
single unique assigned instance or multiple assigned instances for that
partition.
I've been debating whether perhaps I should apply it for each unique
assigned instance instead of at the `partitionId` level, any thoughts? for
REALTIME, we eventually will only allow 1 single`partitionId` to be assigned to
1 set of instances. For OFFLINE, I'm guessing this will look a little
different, since we do allow OFFLINE tables to have more than 1 instance for
each partition for partitioned replica group, but I'm not sure if this will be
the same invariant for strict replica group for OFFLINE once we fix that part
of the code.
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