Successive LINQ queries

I am trying to build a LINQ query to query against a large SQL table (7M+ entries) of Documents.

Each document has many DocumentFields :

My goal is to apply successive filters (from 0 to ~10 filters) on the value field of DocumentField:

Here is an example of the filters I want to apply:

[
  {fieldId: 32, value: "CET20533"},
  {fieldId: 16, value: "882341"},
  {fieldId: 12, value: "101746"}
]

What I want is to retrieve every document in my database that matches all of the filters. For the previous example, I want all documents that have a value of CET20533 for the field with the Id "32", the value 882341 for the field with the Id 16, and so on.

I had a first approach :

List<MyFilter> filters = ... // Json deserialization
db.Documents.Where(document =>
  filters.All(filter =>
     document.DocumentFields.Any(documentField =>
        documentField.Id == filter.Id
        && documentField.Value == filter.Value)));

This approach doesn't work : my filters List isn't a primitive type, and therefore cannot be used in a LINQ query.

I had a second approach, which didn't throw an error at me, but only applied 1 filter :

var result = db.Documents.Select(d => d);
foreach (var filter in filters) {
  var id = filter.Id;
  var value = filter.Value;

  result = result.Where(document => document.DocumentFields.Any(documentField =>
    documentField.Id == id
    && documentField.Value == value));
}

The problem with this approach is, I believe, some sort of a concurrency problem. I applied a simple pause Thread.Sleep(2000) in each iteration of the foreach to test, and it seems to work.

Questions :

• How to remove the pause and still not have concurrency problems ?
• Is there a better way to build my query ?

EDIT :

For more clarity, here is an actual example of a document that matches the previous filters example :