Hi Gilles! Currently Ignite doesn't support automatic serialization of collections, there's an open task for that: https://issues.apache.org/jira/browse/IGNITE-23836 The idea was that you should be able to return values returned from the Tables API directly, like Tuple, and unpack them on the client side. In your case the JobResult object could use custom marshaller, the org.apache.ignite.marshalling.ByteArrayMarshaller will fit just fine here. You need to add resultMarshaller(ByteArrayMarshaller.create()) call to the JobDescriptor builder chain and override resultMarshaller method in the job class so that it also returns ByteArrayMarshaller.create().
BTW, is this intentional that the result generic type of your JobDescriptor is MatchDiscoveryResult but the job result type is JobResult? For the second question it seems that you want colocated execution? You can check the docs here https://ignite.apache.org/docs/ignite3/latest/developers-guide/compute/compute#colocated-execution Basically this will execute the job on a node that have the data for the specified key and then if you need a partition number for something you can get it from the JobExecutionContext Hope this helps, Vadim On Tue, Mar 24, 2026 at 2:17 AM Gilles <[email protected]> wrote: > Hi again, I'm stuck on returning a result from node's compute job to the > client. > > public class MatchDiscoveryJob implements > ComputeJob<MatchDiscoveryQueryArgs, JobResult> { > > @Override > > public CompletableFuture<JobResult> executeAsync(JobExecutionContext > context, MatchDiscoveryQueryArgs args) { > > KeyValueView<MatchDiscoveryCacheKey, MatchDiscoveryEntry> view = > context.ignite().tables() > > .table(MatchDiscoveryEntry.TABLE_NAME) > > .keyValueView(MatchDiscoveryCacheKey.class, MatchDiscoveryEntry.class); > > > ArrayList<Long> reservoir = new ArrayList<>(); > > > // Dummy data, iterating over the view with criteria works well > > > reservoir.add(1L); > > reservoir.add(2L); > > reservoir.add(3L); > > > return CompletableFuture.completedFuture(new JobResult(reservoir)); > > } > > } > > > public class JobResult { > > ArrayList<Long> ids; > > > public JobResult() { > > } > > > public JobResult(ArrayList<Long> ids) { > > this.matchedUserIds = ids; > > } > > > public List<Long> getIds() { > > return new ArrayList<>(ids); > > } > > } > > > > public CompletableFuture<List<Long>> callJob(String affinityKey, > MatchDiscoveryQueryArgs args) { > > Tuple key = Tuple.create().set("open_location", > affinityKey).set("user_id", args.userID); > > JobTarget targetNode = JobTarget.colocated(MatchDiscoveryEntry.TABLE_NAME, > key); > > > JobDescriptor<MatchDiscoveryQueryArgs, MatchDiscoveryResult> descriptor = > > JobDescriptor.builder(MatchDiscoveryJob.class) > > .resultClass(JobResult.class) > > .units(new DeploymentUnit(DISCOVERY_UNIT_NAME, DISCOVERY_UNIT_VERSION)) > > .build(); > > > CompletableFuture<List<Long>> futureResult = ignite.compute() > > .executeAsync(targetNode, descriptor, > args.withAffinityLocation(affinityKey)) > > .thenApply(MatchDiscoveryResult::getIds); > > > List<Long> result = futureResult.join(); // Size of 3, elements all null > > return futureResult; > > } > > > > The result on the client always has the correct size of 3, but all > elements are always null. > > Steps; > > 1. compile jar containing all classes > > 2. start nodes (docker compose up) > > 3. cli deploy the unit to the cluster > > 4. Call the callJob(...) function from a client (non-embedded) > > > > 1. Am I doing anything wrong here? Examples are limited to primitive boxed > types. I've also tried to implement the Serializable interface on > MatchDiscoveryResult, async / sync calls > > 2. Additionally is there a way to query directly in the correct partition > of the node (like in Ignite 2.x)? Or is > Criteria.and(Criteria.columnValue("open_location", > Criteria.equalTo(args.affinityLocation)) enough to stick it to the > partition's affinity? > > Thanks in advance, > > Gilles > > > > > > > > >
