These are the slides from my MongoDB World 2018 talk. Here we present where and how MongoDB Mobile fits into the larger MongoDB data platform, followed by a deep dive into the layered architecture of MongoDB Mobile to understand how the individual components are designed and can be used for your various IoT and edge devices, but more importantly how all of the components come together seamlessly to form the best end-to-end platform for designing your next generation applications for Android and iOS. If you have any questions or are interested in joining the Beta, please reach out to me!

1. MongoDB Mobile
Bringing the Power of MongoDB to Your Device

2. Matt Lord
Senior Product Manager
@mattalord

3. We’ve Come a Long
Way

4. Mobile
Is Transforming Everything
Mobile is becoming not only the new
digital hub, but also the bridge to the
physical world. That’s why mobile will
affect more than just your digital
operations — it will transform your
entire business.
Thomas Husson, Vice President and Principal
Analyst at Forrester Research

5. A Complete Data Platform
● Geographically distributed backend services
○ MongoDB Atlas
■ Point and click active/active global clusters
■ Effortless HA, DR, and low-latency access
○ MongoDB Stitch, Serverless Platform
■ Automatic scaling based on request volume
■ Stitch Query Anywhere
■ Stitch Functions
■ Stitch Triggers
■ Stitch Mobile Sync (coming soon)
● Geographically distributed frontend services
○ MongoDB Mobile
■ IoT and edge devices
■ iOS and Android apps
■ Supporting local offline storage
● Stitch provides a seamless bridge between them

6. MongoDB Mobile

7. The Full Stack
MongoDB Embedded SDK
● A lite version of MongoDB as a library
● C language interface to the library
● Fully passive, no background threads or tasks
MongoDB Drivers
● Swift for iOS, Java for Android
● Existing drivers, extended to support local storage
MongoDB Stitch SDK
● Access to MongoDB Stitch services from Android and iOS
● New Stitch Interfaces for on-device (local) storage
● Synchronization between local and remote
Your Mobile Application
● iOS and Android devices
● Leveraging the power of MongoDB everywhere
● Allowing you to focus on building your GREAT THING
MongoDB Mobile Storage Engine
● K/V storage on top of SQLite
● Very small disk footprint and minimal memory usage
● Energy efficient

8. Platform Details
Operating System OS Details CPUs Devices
iOS, tvOS 10.2+ ARM64
x86_64 (simulators)
Apple, Inc.
Android 5.0/Lollipop+ x86_64
armeabi-v7a
arm64-v8a
Any vendor
(by ABI)
Linux TBD x86_64 Any vendor
macOS X 10.10+ x86_64 Apple, Inc.

9. The Full Stack
MongoDB Stitch SDK
● Packages the entire mobile stack together
● Stitches the frontend and backend together
○ End-to-end Mobile SDK
○ API for local storage
○ API for remote Stitch invocation
○ API for syncing between local and remote
○ Provides a transparent bridge for applications
● iOS SDK: https://github.com/mongodb/stitch-ios-sdk/tree/v4-
alpha
● Android SDK: https://github.com/mongodb/stitch-android-
sdk/tree/v4-alpha
final StitchAppClient client = Stitch.getDefaultAppClient();
final MongoClient mongoClient = client.getServiceClient(LocalMongoDbService.ClientFactory);
MongoCollection<Document> items =
mongoClient.getDatabase(TodoItem.TODO_LIST_DATABASE).getCollection(TodoItem.TODO_LIST_COLLECTIO
N);
public void updateChecked(final ObjectId itemId, final boolean isChecked) {
final Document updateDoc = new Document("$set", new Document(TodoItem.CHECKED_KEY, isChecked));
if (isChecked) {
updateDoc.append("$currentDate", new Document(TodoItem.DONE_DATE_KEY, true));
} else {
updateDoc.append("$unset", new Document(TodoItem.DONE_DATE_KEY, ""));
}
items.updateOne(new Document(TodoItem.ID_KEY, itemId), updateDoc);
...
}
private List<TodoItem> getItems() {
final ArrayList<TodoItem> todoItems = new ArrayList<>();
for (final Document doc : items.find()) {
if (TodoItem.isTodoItem(doc)) {
final TodoItem item = new TodoItem(doc);
todoItems.add(item);
}
}
return todoItems;
}

10. The Full Stack
MongoDB Drivers
● Existing drivers for the given language
○ With a few extensions
■ Open a local storage instance
■ Close a local storage instance
○ Support today for Swift, Java, and C
○ Others created based on demand
● Can be tested directly
○ Swift: https://github.com/mongodb/swift-mongo-
mobile/
○ Java:
http://central.maven.org/maven2/org/mongodb/mongodb-
driver-embedded/
import MongoMobile
…
let client = MongoMobile.create(settings: MongoClientSettings [ dbPath: "test-path" ])
let coll = try client.db("test").collection("foo")
let insertResult = try coll.insertOne([ "test": 42 ])
let findResult = try coll.find([ "_id": insertResult!.insertedId ])
let docs = Array(findResult)

11. The Full Stack
MongoDB Embedded SDK
● Lite version of MongoDB formed into a library
○ C ABI
○ Auth, Replication, Sharding, etc. removed
○ Supports only the mobile storage engine
○ Passive: no background threads
○ Light: disk, memory, energy
● C Interface
○ Low level
○ Not designed to be used directly
○ Drivers should be extended to invoke it
● Availability
○ Builds out of MongoDB 4.0+ community tree
○ Pre-built binary packages for mobile targets
auto status = mongo_embedded_v1_status_create();
mongo_embedded_v1_init_params params;
...
auto lib = mongo_embedded_v1_lib_init(&params, status);
auto config_yaml = ...
auto instance = mongo_embedded_v1_instance_create(lib,
config_yaml, status);
auto client = mongo_embedded_v1_client_create(instance, status);
auto [inputMessage, inputMessageLen] = ...
auto [output, outputLen] = ...
int err = mongo_embedded_v1_client_invoke(client,
inputMessage, inputMessageLen,
&output, &outputLen,
status);

12. The Full Stack
Mobile Storage Engine
● Leverages SQLite as a K/V store
○ Single SQLite database called “mobile”
○ Table names follow the WiredTiger filesystem /
dictionary naming convention
○ Every entity you create
■ database, collection, index, ...
■ Stored in a dedicated table as K/V pairs
● Can be tested with standard mongod
./buildscripts/scons.py mongod --mobile-se=on
./build/opt/mongo/mongod --storageEngine=mobile
sqlite> .database
main: /.../mobile.sqlite
sqlite> .tables
_mdb_catalog index-1-1419396644176400596
collection-0-1419396644176400596 index-1-9204882299253173129
collection-0-9204882299253173129
sqlite> select sql from sqlite_master where name='collection-0-9204882299253173129';
CREATE TABLE "collection-0-6881873531296038739"(rec_id INT, data BLOB, PRIMARY
KEY(rec_id))
sqlite> select sql from sqlite_master where name='index-1-9204882299253173129';
CREATE TABLE "index-1-9204882299253173129"(key BLOB PRIMARY KEY, value BLOB)
sqlite> select * from `collection-0-9204882299253173129`;
rec_id data
---------- ----------
1 2

13. Andrew Morrow
Embedded SDK Lead
Matt Broadstone
Swift Driver Lead
Kaitlin Mahar
Swift Driver Engineer
Ross Lawley
Java Driver Lead
Q&A with the Engineers
Eric Daniels
Stitch Lead

14. Visit us at the MongoDB Mobile/Stitch booth!
Q&A with the Team