Limiting page size with $first in REST

Limiting page size prevents overwhelming clients or servers when querying large datasets. In REST, Data API builder (DAB) uses the $first parameter to control how many records are returned in a single response. DAB applies cursor-based pagination internally, but $first can be used even when continuation isn't required.

Go to the GraphQL version of this document.

Overview

If $first is omitted, the default page size applies automatically.

Usage pattern

GET /api/{entity}?$first=N

Example

Limit the results to five books.

GET /api/books?$first=5

Conceptual SQL

SELECT TOP (5)
  id,
  sku_title AS title
FROM dbo.books
ORDER BY id ASC;

Sample response

{
  "value": [
    { "id": 1, "title": "Dune" },
    { "id": 2, "title": "Foundation" },
    { "id": 3, "title": "Hyperion" },
    { "id": 4, "title": "I, Robot" },
    { "id": 5, "title": "The Martian" }
  ]
}

Validation rules

Example error message

Invalid number of items requested, first argument must be either -1 or a positive number within the max page size limit of 100000. Actual value: 0

Example configuration

{
  "runtime": {
    "pagination": {
      "default-page-size": 100,
      "max-page-size": 100000
    }
  },
  "entities": {
    "Book": {
      "source": {
        "type": "table",
        "object": "dbo.books"
      },
      "mappings": {
        "sku_title": "title",
        "sku_price": "price"
      },
      "relationships": {
        "book_category": {
          "cardinality": "one",
          "target.entity": "Category",
          "source.fields": [ "category_id" ],
          "target.fields": [ "id" ]
        }
      }
    },
    "Category": {
      "source": {
        "type": "table",
        "object": "dbo.categories"
      },
      "relationships": {
        "category_books": {
          "cardinality": "many",
          "target.entity": "Book",
          "source.fields": [ "id" ],
          "target.fields": [ "category_id" ]
        }
      }
    }
  }
}

See also