Skip to content

[multistage] Fix Bug in MailboxInfo Ordering #16224

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
itschrispeck merged 1 commit into from
Jun 30, 2025
Merged

[multistage] Fix Bug in MailboxInfo Ordering #16224

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 9 additions & 0 deletions ...ain/java/org/apache/pinot/query/planner/physical/v2/PlanFragmentAndMailboxAssignment.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
Expand Down Expand Up @@ -253,6 +254,14 @@ private static List<MailboxInfo> createMailboxInfo(Map<Integer, QueryServerInsta
for (var entry : workersByUniqueHostPort.entrySet()) {
result.add(new MailboxInfo(entry.getKey().getHostname(), entry.getKey().getQueryMailboxPort(), entry.getValue()));
}
// IMP: Return mailbox info sorted by workerIds. This is because SendingMailbox are created in this order, and
// record assignment for hash exchange follows modulo arithmetic. e.g. if we have sending mailbox in order:
// [worker-1, worker-0], then records with modulo 0 hash would end up in worker-1.
// Note that the workerIds list will be >1 in length only when there's a parallelism change. It's important to
// also know that MailboxSendOperator will iterate over this List<MailboxInfo> in order, and within each iteration
// iterate over all the workerIds of that MailboxInfo. The result List<SendingMailbox> is used for modulo
// arithmetic for any partitioning exchange strategy.
result.sort(Comparator.comparingInt(info -> info.getWorkerIds().get(0)));
return result;
}

Expand Down