[FIXED] CosmosDB SQL API Java SDK v.4 ReadAllItems method does not return results

Issue

I encountered some obstackles with getting results from cosmos db sql api using methods:

.readAllItems(partitionKey, classType)

.readAllItems(partitionKey, options, classType)

Above methods work fine when I have flat structure of class. I mean no subclasses nested inside my model class. Below is class example, which does not work:

public class Root {
    public Root(){};

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public Subclass getSubclass () {
        return subclass;
    }

    public void setSubclass (Subclass subclass) {
        this.subclass= subclass;
    }

    private String id = "";
    private Subclass subclass= new Subclass ();
}

My subclass just contains partitionKey for simplicity.

public class Subclass {

    public String getPk() { return pk; }

    public void setPk(String pk) {
        this.pk = pk;
    }

    private String pk="";
}

With such "structure" I can easily create items inside container, with proper values of partition key, but I am not able to load them again just using partitionKey value. Here is code snippet for reading them from cosmosdb.

PartitionKey partitionKey = new PartitionKey("properValueWhichWorksWithNoNestedClassesInsideRoot");
CosmosPagedFlux<Root> pagedFluxResponse = container.readAllItems(partitionKey, Root.class);
try {
   double totalRequestCharge = pagedFluxResponse.byPage(preferredPageSize).flatMap(fluxResponse -> {
      entities.addAll(fluxResponse.getResults());

      return Mono.just(fluxResponse.getRequestCharge());
   })
   .reduce(0.0, (x1, x2) -> x1 + x2)
   .block();

   logger.info("Query charge: {}", totalRequestCharge);
} catch(Exception err) {
         err.printStackTrace();
}

return entities;

I am not quite sure if I am doing sth wrong or it is bug, beacuse I use the same code with .queryItems(query, queryOptions, classType), which also returns CosmosPageFlux instead of .readAllItems and it works perfectly fine.

I use such dependancy:

<dependency>
   <groupId>com.azure</groupId>
   <artifactId>azure-cosmos</artifactId>
   <version>LATEST</version>
</dependency>

I also used some specific versions intead of LATEST and it does not work.

Solution

I've tested in my side and found some interesting things.

readAllItems is a function which achieved by SqlQuery, so when I debug your situation which put the partition key in a sub property, it will generate a sql like this:

So, obviously it can got any response so that the result of readAllItems returns none. You'd better to use queryItems directly.

Answered By - tiny-wa
Answer Checked By - Robin (JavaFixing Admin)