Hierarchy read API of collections in edit mode is failing with server error

[amitpriyadarshi]

@Krishnaj20 @vinukumar-vs @AmiableAnil
Collection hierarchy read api is failing with server error with below response:

{
"id": "api.content.hierarchy.get",
"ver": "3.0",
"ts": "2022-06-08T11:21:25ZZ",
"params": {
"resmsgid": "b9352f77-a1c7-424b-baae-1b8b2d44f261",
"msgid": null,
"err": "ERR_SYSTEM_EXCEPTION",
"status": "failed",
"errmsg": "Something went wrong in the server while processing the request"
},
"responseCode": "SERVER_ERROR",
"result": {}
}

Analysis:
There is an external property named relational_metadata introduced in release-4.7.0 against the collection objects. If this property is null for a Live collection object and we call update hierarchy API, its draft version gets created in neo4j and the external property gets inserted into Cassandra against the draft object. In this case, the relational_metadata field gets set as "null" as a string (instead of null).

Because of which hierarchy read API throws an exception while parsing this value to object and throws Server Exception in response.

There are about 780 draft versions of collections that are impacted by this issue. This is impacting many users to update the already published collection.

[vinod303]

@amitpriyadarshi i have also noticed the same issue

[anandvarada]

Hi @Krishnaj20 @vinukumar-vs @AmiableAnil
We have users who are waiting for the issue fix as they are unable to edit / publish their collections, need a fix on priority

[kameshbhr]

@Krishnaj20 @vinukumar-vs This is a P1 issue that requires immediate hotfix as it is blocking DIKSHA users to update and publish any collection.

[Krishnaj20]

Team has started looking into it as a S1/P1 issue. Patch will be made available as soon as the root cause is identified and fixed.

@vinukumar-vs

[Krishnaj20]

@anandvarada @amitpriyadarshi - From this description, the team is not able to understand the actual scenario which is causing this issue. Pls do add those details.
@vinukumar-vs has set up a meeting to discuss more about this.

[Krishnaj20]

@kameshbhr & @anandvarada - This is happening only when Org Admin opens collections published by others from the 'All textbooks' tab. @amitpriyadarshi can correct the data for the impacted textbooks to unblock users.
Please do note that this is not a recently introduced bug - it was there since 4.7 SunbirdEd release and the scenario to replicate this is also straight forward. We've not seen this issue reported by the community (either by SunbirdEd (coKreat) or by the adopter QA team) when testing 4.7 or the subsequent releases. Therefore, it looks like a not so important workflow if it isn't part of the community's test scenarios. We will fix this issue in the current ongoing release (5.0).

[Krishnaj20]

@amitpriyadarshi - are you able to replicate the issue for the above mentioned scenarios?

[Jayaprakash8887]

@vinod303 Kindly check these scenarios as well and confirm.

[vinod303]

@Jayaprakash8887 @Krishnaj20 @kameshbhr @anandvarada @vinukumar-vs
For all the scenarios, the relational_metadata field gets set as "null" as a string, causing the issue.

For
2. Unable to edit Textbooks:
We are able to replicate as we did in the joint call, when the org admin open the content from the "All textbook" tab

3. Unable to load textbooks in VDN project
The problem as above. But the scenario here..
The creator of the textbook (who is also a orgadmin), created a project adding these textbooks to the project and published it.
Then after two days, he (ORGADMIN) opens the textbook via the "All textbook" tab. And the reason mentioned by @Jayaprakash8887 and @amitpriyadarshi the textbook did not open/open blank screen due to server error.
Telemetry data also shows that, the user has opened the textbook from the "All Textbook" tab
So, post this, when the user tried access textbook via the project in VDN, there is call from VDN to DIKSHA happens to fetch the textbooks, but due to the issue mentioned in the previous line, textbook will not load .

1. Unable to edit Courses to add a Keyword
Here also, the issue is due to relational_metadata field gets set as "null" as a string. But, i am not able to find still in what scenario its happens for a course

[Jayaprakash8887]

@vinod303 @amitpriyadarshi Do you mean these flows were tested on a Draft textbook which has "null" relational_metadata? In that case, I think we have only 1 issue to address, right?

[Jayaprakash8887]

Patch for this issue is available as part of release-4.9.1 tracked under tickect https://project-sunbird.atlassian.net/browse/SB-30307

[Jayaprakash8887]

RCA: When the content-update (v3) API is invoked on a published collection, "relational_metadata" column in the cassandra is getting insert with null as string data for the newly created image node.

[vinukumar-vs]

@Krishnaj20 The fix is ready, we are verifying in dev. Once we verify we will push to preprod.
JIRA ticket