Graphql-ruby: Duplicated records on paged/sorted connections

[musashinm]

As we talked at Slack, I'm facing a problem with GraphQL::Pro::RelationConnection when I sort Relations by any other field instead ID. I'm receiving duplicated records on subsequent pages.

I already tried to include Primary Key to order clause (as you can see it below).

Connection Definition

# ./graphql/types/query_type.rb
QueryGQLType = GraphQL::ObjectType.define do
  ...
  connection :table, TableWithCountConnection, max_page_size: 50 do
    resolve ->(_obj, _args, _ctx) { Table.joins(:child_table).order('"child_table"."index", "table"."id"') }
  end
  ...
end

# ./graphql/connections/table_with_count_connection.rb
TableWithCountConnection = TableType.define_connection do
  name 'TableWithCountConnection'
  field :count do
    type types.Int
    resolve ->(obj, _args, _ctx) { obj.nodes.count }
  end
end

GraphQL Query for First Page

query { 
  table(first: 10) { 
    edges { node { id title } } 
    pageInfo { startCursor endCursor }
  } 
}

GraphQL Response for First Page

{
  "data": {
    "table": {
      "edges": [
        {
          "node": { "id": "2", "title": "Record #1" },
          "cursor": "WyIxLjAiLDJd"
        },
        {
          "node": { "id": "18", "title": "Record #10" },
          "cursor": "WyI2LjAiLDE4XQ=="
        },
        {
          "node": { "id": "31", "title": "Record #11" },
          "cursor": "WyIzLjAiLDMxXQ=="
        },
        {
          "node": { "id": "34", "title": "Record #12" },
          "cursor": "WyIxNC4wIiwzNF0="
        },
        {
          "node": { "id": "32", "title": "Record #15" },
          "cursor": "WyIxMi4wIiwzMl0="
        },
        {
          "node": { "id": "37", "title": "Record #16" },
          "cursor": "WyI0LjAiLDM3XQ=="
        },
        {
          "node": { "id": "33", "title": "Record #17" },
          "cursor": "WyIxMy4wIiwzM10="
        },
        {
          "node": { "id": "35", "title": "Record #19" },
          "cursor": "WyIxNS4wIiwzNV0="
        },
        {
          "node": { "id": "21", "title": "Record #2" },
          "cursor": "WyI5LjAiLDIxXQ=="
        },
        {
          "node": { "id": "17", "title": "Record #3" },
          "cursor": "WyI1LjAiLDE3XQ=="
        }
      ],
      "pageInfo": {
        "startCursor": "WyIxLjAiLDJd",
        "endCursor": "WyI1LjAiLDE3XQ=="
      }
    }
  }
}

SQL Query for First Page

SELECT "table".*
FROM "table" JOIN "child_table" ON "table"."id" = "child_table"."id"
ORDER BY "child_table"."index", "table"."id"
LIMIT 11

GraphQL Query for Second Page

query { 
  table(first: 10, after: "WyI1LjAiLDE3XQ==") { 
    edges { node { id title } } 
    pageInfo { startCursor endCursor }
  } 
}

GraphQL Response for Second Page

{
  "data": {
    "table": {
      "edges": [
        {
          "node": { "id": "34", "title": "Record #12" },
          "cursor": "WyIxNC4wIiwzNF0="
        },
        {
          "node": { "id": "32", "title": "Record #15" },
          "cursor": "WyIxMi4wIiwzMl0="
        },
        {
          "node": { "id": "37", "title": "Record #16" },
          "cursor": "WyI0LjAiLDM3XQ=="
        },
        {
          "node": { "id": "33", "title": "Record #17" },
          "cursor": "WyIxMy4wIiwzM10="
        },
        {
          "node": { "id": "35", "title": "Record #19" },
          "cursor": "WyIxNS4wIiwzNV0="
        },
        {
          "node": { "id": "21", "title": "Record #2" },
          "cursor": "WyI5LjAiLDIxXQ=="
        },
        {
          "node": { "id": "17", "title": "Record #3" },
          "cursor": "WyI1LjAiLDE3XQ=="
        },
        {
          "node": { "id": "23", "title": "Record #4" },
          "cursor": "WyIxMS4wIiwyM10="
        },
        {
          "node": { "id": "19", "title": "Record #5" },
          "cursor": "WyI3LjAiLDE5XQ=="
        },
        {
          "node": { "id": "24", "title": "Record #6" },
          "cursor": "WyIyLjAiLDI0XQ=="
        }
      ],
      "pageInfo": {
        "startCursor": "WyIxNC4wIiwzNF0=",
        "endCursor": "WyIyLjAiLDI0XQ=="
      }
    }
  }
}

SQL Query for Second Page

SELECT "table".*
FROM "table" JOIN "child_table" ON "table"."id" = "child_table"."id"
WHERE ((("child_table"."index" > '5.0') OR ("child_table"."index" = '5.0' AND "table"."id" > 17)))
ORDER BY "child_table"."index", "table"."id"
LIMIT 11

Ruby and Gems Versions

ruby 2.4.1
rails 4.2.9
graphql-pro 1.4.8
graphql-batch 0.3.3

[rmosolgo]

Hi, thanks for the great bug report! Sorry this is happening ... so confusing!

I was just poking around the tests for this feature and I noticed a strange bug. If join a table, but the main table has a column with the same name as the joined table, it will use a value from the main table.

Is that possible here, does the tables table have an index column?

[musashinm]

@rmosolgo, yes. The main table have a column with the same name.

[musashinm]

@rmosolgo, based on what you said about columns with the same name I tried a workaround and just worked.

I founded two options:

1. Rename the column on the child table
2. Select the column from the child table (the same used to order query) and suppress the other one from SELECT

😉

[rmosolgo]

I'm glad to hear that you found a workaround that works for you!

In the meantime, I've updated graphql-pro to support that kind of situation, see #939 . So, if you get a chance to try it out, let me know how it goes. Otherwise, I'm glad the workaround did the job 😸

[musashinm]

@rmosolgo, I'll try it ASAP 😉

[musashinm]

@rmosolgo, it works... I already removed my workaround. 😄

[rmosolgo]

yay, glad to hear it!