Support value variables for paging params (offset, after, first)

[disconsented]

{

 var(func: eq(account, "100")){
   client{
       cid as uid  
   }
   msg as message_limit
 }
 messageCount(func: uid(cid)){
        count(messages)
   messages(orderdesc: timestamp, offset: val(msg)){
        uid
        payload
        timestamp
   }
 }
}

message_limit here is message_limit:int . .
The essential point is that I want to be able to set values in the database to use as limits application side. The above results in : strconv.ParseInt: parsing "msg": invalid syntax which seems inconsistent considering that variables can be used for ordering as suggested by the documentation.

[danielmai]

Using val() with offset sounds like a valid feature.

Took another look at your specific use case. You’d like to do message limiting, so would it be better to use first: to retrieve only N messages? Instead of offset, which skips the first N messages and returns the rest.

[MichelDiz]

I think this feature could be very handy e.g:

{
#dummy query as empty query you can't use, other than aggregation.
  var(func: uid(0x1)){  
    amount as math(5)
    page   as math(2)
    OST as math(amount * page)
  }
  q(func: has(somePred), 
    orderasc: otherPred, first: val(amount), offset: val(OST) ) {
    expand(_all_)
  }
}

[romshark]

I think I faced a similar problem working on my dgraph tech-demo. I'm trying to implement pagination and this is the query I assumed to work:

query PostsPage(
  $first: int = 4,
  $id: string = "ce9f834c2fd143e7a0994cd01564d990"
) {
  var(func: eq(Post.id, $id)) {
    p as uid
  }
  posts(
    func: has(Post.id),
    orderasc: Post.id,
    after: val(p),
    first: $first
  ) {
    uid
    Post.id
    Post.title
    Post.contents
  }
}

Unfortunately, it seems like I can't use p as an argument for after:

": strconv.ParseUint: parsing \"p\": invalid syntax"

I suddenly need 2 roundtrips to get the job done:

• fetch the uid by id
• then fetch the page using the uid

This is obviously bad because it could have been done with just a single simple query.
Please correct me if I'm wrong.