Transaction support in RavenDB

All the previous examples have assumed that a single unit of work can be achieved with a single IDocumentSession and a single call to SaveChanges, and for the most part this is definitely true. Sometimes however we do need multiple calls to SaveChanges for one reason or another, but we want those calls to be contained within a single atomic operation.

RavenDB supports System.Transactions for multiple operations against a RavenDB server, or even against multiple RavenDB servers.

The client code for this is as simple as::

using (var transaction = new TransactionScope())
{
	BlogPost entity = session.Load<BlogPost>("blogs/1");

	entity.Title = "Some new title";

	session.SaveChanges();

	session.Delete(entity);
	session.SaveChanges();

	transaction.Complete();
}

If at any point any of this code fails, none of the changes will be enacted against the RavenDB document store.

The implementation details of this are not important, although it is possible to see that RavenDB does indeed send a transaction Id along with all of the the HTTP requests under this transaction scope as shown here:

POST /bulk_docs HTTP/1.1
Raven-Transaction-Information: 975ee0bf-cac9-4b8e-ba29-377de722f037, 00:01:00
Accept-Encoding: deflate,gzip
Content-Type: application/json; charset=utf-8
Host: 127.0.0.1:8081
Content-Length: 300
Expect: 100-continue

[
  {
    "Key": "blogs/1",
    "Etag": null,
    "Method": "PUT",
    "Document": {
      "Title": "Some new title",
      "Category": null,
      "Content": null,
      "Comments": null
    },
    "Metadata": {
      "Raven-Entity-Name": "Blogs",
      "Raven-Clr-Type": "ConsoleApplication5.Blog, ConsoleApplication5",
      "@id": "blogs/1",
      "@etag": "00000000-0000-0200-0000-000000000002"
    }
  }
]

A call to commit involves a separate call to another HTTP endpoint with that transaction id:

POST /transaction/commit?tx=975ee0bf-cac9-4b8e-ba29-377de722f037 HTTP/1.1
Accept-Encoding: deflate,gzip
Content-Type: application/json; charset=utf-8
Host: 127.0.0.1:8081
Content-Length: 0