[turtle4]

I don't think that's true. From what I perused of the driver implementations, I think that as calls are made, the driver basically builds an AST up, and then when you call run() it compacts it and sends it over to the DB. ie, when you call filter() you aren't actually filtering, you're adding a filter operation to the AST.

I would think that would allow Rethink to analyze the structure of the query and perform appropriate optimizations.

[BringTheTanks]

I'm talking about map(), and you're talking about filter().

Here's the code in question:

  .map(function(album){
    return {artist : album("vendor")("name")}
  })

If this is simply adding a node to an AST, it could be expressed without a function:

  .map({artist : ['album','vendor','name']})

Using a function for this would be quite superfluous.

[coffeemug]

You can express it both ways in RethinkDB, and they'd both do the same thing -- add a node to the AST. The function is just a convenience syntax.