[BUG] Nested/Sub Aggregations are not sending back buckets containing the data

[joelbolt35]

What is the bug?

This is a duplicate bug from the elastic search java client:
elastic/elasticsearch-java#87

How can one reproduce the bug?

Create ANY nested aggregation for terms. There is no way to retrieve results

What is the expected behavior?

Nested Queries work.

What is your host/environment?

Linux (Ubuntu 18.04). Using opensearch-rest-clientv2.1.0 and opensearch-javav2.0.0

Do you have any screenshots?

the docCount is correct but I can't see the data since the deserializer tossed it.

[dblock]

Would appreciate a PR with the fix. Please be mindful of not copying non-APLv2 code.

[joelbolt35]

@dblock
The elastic search specification update that this fix needs is fixed here: elastic/elasticsearch-specification#1243

And I see here that they use code generation from that spec: elastic/elasticsearch-java@7444423

How is this code generation done? I need to generate it since this this code gen appears to fix the issue.

[dblock]

@joelbolt35 TBH I don't know. I don't think we generated any code here since the fork, and the spec has diverged. We thus don't want to use the upstream elasticsearch-specification. I suppose it would be ok to make small fixes by hand?

In the short term, we did start forking elasticsearch-specification at the time, but didn't finish it. We still can at its last APLv2 iteration if that's the right thing to do. WDYT?

The long term plan I'd like to take is opensearch-project/opensearch-clients#19. It's similar to what elastic is doing, except we chose different tooling. For opensearch-java this means swapping the elastic spec for https://github.com/opensearch-project/opensearch-api-specification (or its output). It would be amazing if someone could attempt that, even if to see what the gap is.

[pchaitu]

I am also struggling with the same issue with Nested and Multi term aggregation, as well, any chances of quick fix on this?

[abhinav-nath]

Can someone please help - how to parse sub-aggregations from filter aggregations? This is a big issue for rendering multi-select facets and refraining me from using this new client.

There is no way to extract sub-aggregations:

[dblock]

@abhinav-nath Someone (you?) needs to contribute a fix for this in OpenSearch (without copying ES code). I don't think there's another way.

[abhinav-nath]

@dblock - I have created a PR (#234). Please review it.

[oana-danescu-idnow]

Any idea when this will be released?

[dblock]

Please add your +1 to #253

[VachaShah]

This was released in v2.2.0.