CallProcedure deserialization is not working with Read-Only queries

[Ivan-Gyoshev]

We are using a Redis graph read-only replica and performing read-only queries. In standard scenarios when the result is a specific value like a string or long there aren't any problems, but in the case when we are expecting nodes, the deserialization is calling inside it a 'GRAPH.QUERY' and the read-only replica which is only accepting 'GRAPH_RO.QUERY' is throwing an exception.

The full path to the method is ResultSet>RecordIterator>DeserializeScalar>DeserializeNode>_graphCache.GetLabel>_labels.GetCachedData>GetProcedureInfo>CallProcedure

[tombatron]

Thanks for reporting this!

I'll take a look at the issue and your pull request very soon.

[tombatron]

@Ivan-Gyoshev It just occurred to me 🤦‍♂️, would you mind trying the method GraphReadOnlyQuery (or GraphReadOnlyQueryAsync)?

The implementation is VERY similar to the pull request that you opened.

[Ivan-Gyoshev]

Hey @tombatron ,

Do you mean using the already implemented method GraphReadOnlyQuery instead of creating the new one(ReadOnlyQuery) which I put in the pull request?

[tombatron]

Yes.

Also, could I get some sample data and a sample procedure to replicate for a test.

I'd also like to check Jedis's RedisGraph support for the same issue since my goal here is to essentially replicate the "official" support.

[tombatron]

Yes.

Also, could I get some sample data and a sample procedure to replicate for a test.

I'd also like to check Jedis's RedisGraph support for the same issue since my goal here is to essentially replicate the "official" support.

[Ivan-Gyoshev]

Hello,
I updated my pull request.

Here is a little sample of how you can reproduce this issue:

Connect to your master Redis graph

ConnectionMultiplexer connectionMultiplexer = ConnectionMultiplexer.Connect("localhost:6379,abortConnect=false");
var db = connectionMultiplexer.GetDatabase();
var redisGraph = new RedisGraph(db);

    // Insert data
    string firstPersonQuery = "CREATE (:Person {username: 'John', age: 20})";
    string secondPersonQuery = "CREATE (:Person {username: 'Peter', age: 23})";
    string thirdPersonQuery = "CREATE (:Person {username: 'Steven', age: 30})";

    redisGraph.GraphQuery("demo", firstPersonQuery);
    redisGraph.GraphQuery("demo", secondPersonQuery);
    redisGraph.GraphQuery("demo", thirdPersonQuery);`

After you enter some sample data in your graph, you have to connect to your read-only replica and read this data.
Connect to your Redis graph replica

ConnectionMultiplexer replicaConnection = ConnectionMultiplexer.Connect("localhost:6378,abortConnect=false");
       var dbReplica = replicaConnection.GetDatabase();
       var redisGraphReplica = new RedisGraph(dbReplica);

    // Read from the read-only replica
    string readQuery = "MATCH x=(p:Person) RETURN nodes(x) as nodes";

    ResultSet records = redisGraphReplica.GraphReadOnlyQuery("demo", readQuery);

    List<Person> result = new List<Person>();

    foreach (Record record in records) // Here it throws the exception (On the iteration)
    {
        var nodes = record.GetValue<object[]>("nodes");

        foreach (var node in nodes)
        {
            if (node is Node castedNode)
            {
                Person person = GetPersonInfo(castedNode);
                result.Add(new Person(person.Name, person.Age));
            }
        }
    }

`

As I described above, when you execute the read-only query and have a result, in the process of deserializing the nodes in the result, the StackExchange.Redis driver is throwing an exception because the deserialization process internally is making GRAPH.QUERY call instead of GRAPH_RO.QUERY

[tombatron]

@Ivan-Gyoshev Would you mind trying: https://www.nuget.org/packages/NRedisGraph/1.7.0-rc ?

If that works for you I'll finalize my changes and publish version 1.7.0.

[Ivan-Gyoshev]

Yes, I tested it now and it seems to work fine. :)