Parse query from LocalDataStore for object with PFRelation returns empty

[MatthieuTnsc]

I am trying to implement Local datastore in my application but I have an issue when I need to query relation from local Datastore.

Here is my query :

var relation:PFRelation = PFUser.currentUser()!.relationForKey("Friendship")
var query:PFQuery = relation.query()!

This query returns what I'm looking for when fetched by network but then I Pin all the results and re-query from localDatastore, and the result is empty.

I am using the newest Parse iOS SDK (1.8.1)

This issue is linked with these topics :

• (apparently "on hold") https://developers.facebook.com/bugs/444556112335977/
• (said it was fixed in 1.7.3) https://developers.facebook.com/bugs/938451159512610/

[nlutsenko]

Can you share a full code snippet that fails for you. An ideal scenario would be a failing unit test or a full repro project on github.

[MatthieuTnsc]

Here is a code snippet with parts of the code I use : https://gitlab.com/snippets/7703
I don't have time nowadays to create a full repro project on github but if my snippet isn't enough I'll try to.

[dtaitz]

Has this been resolved? I am also having this same issues (PFRelation queries in the localdatatsore).

[Rollaway]

I'm getting this with 1.8.5. Let me know if there's anything I can do to help squash.

[nlutsenko]

Hey guys, the most helpful thing here would be to get a repro project from anyone of you that has this issue reproduced. Or a failing unit test?

[dtaitz]

Hi @nlutsenko, I took some time to further investigate this issue and realized that the issue was not in querying the localDatastore but actually pinning large amounts of objects to the localDatastore using the method +(BFTask *)pinAllInBackground:(NSArray *)objects.

I realized this because when I pinned (using pinAllInBackground:) and then did a localDataStore query for a PFRelation of only 6-10 objects, I was able to get my desired results. On the other hand, when I did the same two methods with a PFRelation of ~600 and ~1000 objects, I failed to get the objects when I did the localDatastore query (yet the BFTask returned a result of 1 which made me think the pinning work).

To test this assumption, I decided to iterate through the PFRelation of ~1000 objects, and then individually pin each object using - (BFTask *)pinInBackground. After doing this, I did the same local query on the PFRelation and was able to retrieve my desired objects.

Hope this helps. Happy to clarify.

[nlutsenko]

Great, this definetly helps. Any chance you can setup a project that shows the issue?

[dtaitz]

Yeah, I will build something now. Shouldn't take too long.

[dtaitz]

@nlutsenko I just shared you with a fairly simple that replicates this issue. It logs the results of the query to server, the pin task, and the local query to show what is going wrong.

[nlutsenko]

@dtaitz, many thanks for the repro project, I can see the issue now.
It looks like to be related to the fact that you have the same User inside the relation, which resets the value of the relation back to the original state.

I'll look into the ways to fix it overall - but in the meantime, removing the currentUser from inside the relation fixes the problem in your case.

[dtaitz]

Thank you! That makes sense. I appreciate you pointing that out  

I appreciate you taking the time to help!

On Sat, Oct 10, 2015 at 8:49 PM, Nikita Lutsenko notifications@github.com
wrote:

@dtaitz, many thanks for the repro project, I can see the issue now.
It looks like to be related to the fact that you have the same User inside the relation, which resets the value of the relation back to the original state.

I'll look into the ways to fix it overall - but in the meantime, removing the currentUser from inside the relation fixes the problem in your case.

Reply to this email directly or view it on GitHub:
#72 (comment)

[dtaitz]

@nlutsenko removing the Current User from the PFRelation solves the issue on the sample project I gave you but not on my actual project.

I keep coming across this lock with [User currentUser] when trying to find workarounds for my current problem with querying the localdatastore with PFRelations.

https://gist.github.com/dtaitz/add05892cec971f40766

I update my [User currentUser] a decent amount at launch of the app but have not seen this issue until recently.

Please let me know what I can do to help