Nicholas Tang, who leads 10gen’s North American support team, recently presented on Performance Tuning and Monitoring Using MongoDB Management Service (MMS) in a live webcast. In the session, Nicholas explained what MMS is, why you should use it, how you can set it up and how to use it for performance tuning. He then gave some examples of real-world scenarios where he worked with customers to use MMS to diagnose and debug performance issues using MMS. The video and slides are now available online below.
To start monitoring your MongoDB deployment today, sign up for a free MMS account at mms.10gen.com.
The MongoDB Java Driver 3.0
By Trisha Gee , MongoDB Java Engineer and Evangelist You may have heard that the JVM team at 10gen is working on a 3.0 version of the Java driver. We’ve actually been working on it since the end of last year, and it’s probably as surprising to you as it is to me that we still haven’t finished it yet. But this is a bigger project than it might seem, and we’re working hard to get it right. So why update the driver? What are we trying to achieve? Well, the requirements are: More maintainable More extensible Better support for ODMs, third party libraries and other JVM languages More idiomatic for Java developers That’s all very nice, but it’s a bit fluffy. You can basically summarise that as “better all round”. Which is probably the requirement of any major upgrade. Since it’s too fluffy to guide us in our development, we came up with the following design goals. Design Goals Consistency Cleaner design Intuitive API Understandable Exceptions Test Friendly Backwards compatible Consistency Java developers using the driver will have encountered a number of inconsistencies: the way you do things in the shell, or in other drivers, is not always the same way you do things in the Java driver. Even using just the Java driver, methods are confusingly named (what’s the difference between createIndex and ensureIndex , for example?); the order of parameters is frequently different; often methods are overloaded but sometimes you chain methods; there are helpers such as QueryBuilder but sometimes you need to manually construct a DBObject , and so on. If you’re working within the driver, the inconsistencies in the code will drive you mad if you’re even slightly OCD: use of whitespace, position of curly braces, position of fields, mixed field name conventions and so on. All of this may seem pedantic to some people, but it makes life unnecessarily difficult if you’re learning to use the driver, and it means that adding features or fixing bugs takes longer than it should. Cleaner Design It’s easy to assume that the driver has a single, very simple, function - to serialise Java to BSON and back again. After all, its whole purpose is to act as a facilitator between your application and MongoDB, so surely that’s all it does - turn your method call and Java objects into wire-protocol messages and vice versa. And while this is an important part of what the driver does, it’s not its only function. MongoDB is horizontally scalable, so that means your application might not be talking to just a single physical machine - you could be reading from one of many secondaries, you could be writing to and reading from a sharded environment, you could be working with a single server. The driver aims to make this as transparent as possible to your application, so it does things like server discovery, selects the appropriate server, and tries to reuse the right connection where appropriate. It also takes care of connection pooling. So as well as serialisation and deserialisation, there’s a whole connection management piece. The driver also aims to provide the right level of abstraction between the protocol and your application - the driver has a domain of its own, and should be designed to represent that domain in a sane way - with Documents, Collections, Databases and so on exposed to your application in a way that you can intuitively use. But it’s not just application developers that are using the driver. By implementing the right shaped design for the driver, we can make it easier for other libraries and drivers to reuse some of the low-level code (e.g. BSON protocol, connection management, etc) but put their own API on the front of it - think Spring Data , Morphia , and other JVM languages like Scala. Instead of thinking of the Java driver as the default way for Java developers to access MongoDB, we can think of this as the default JVM driver, on top of which you can build the right abstractions. So we need to make it easier for other libraries to reuse the internals without necessarily having to wrap the whole driver. All this has led us to design the driver so that there is a Core, around which you can wrap an API - in our case, we’re providing a backward-compatible API that looks very much like the old driver’s API, and we’re working on a new fluent API (more on that in the next section). This Core layer (with its own public API) is what ODMs and other drivers can talk to in order to reuse the common functionality while providing their own API. Using the same core across multiple JVM drivers and libraries should give consistency to how the driver communicates with the database, while allowing application developers to use the library with the most intuitive API for their own needs. Intuitive API We want an API that: Feels natural to Java developers Is logical if you’ve learnt how to talk to MongoDB via the shell (since most of our documentation references the shell) Is consistent with the other language drivers. Given those requirements, it might not be a surprise that it’s taking us a while to come up with something that fits all of them, and this process is still in progress. However, from a Java point of view, we would like the following: Static typing is an advantage of Java, and we don’t want to lose that. In particular, we’re keen for the IDE to help you out when you’re trying to decide which methods to use and what their parameters are. We want Cmd+space to give you the right answers. Generics. They’ve been around for nearly 10 years, we should probably use them in the driver We want to use names and terms that are familiar in the MongoDB world. So, no more DBObject , please welcome Document . More helpers to create queries and objects in a way that makes sense and is self-describing The API is still evolving, what’s in Github WILL change. You can take a look if you want to see where we are right now, but we make zero guarantees that what’s there now will make it into any release. Understandable Exceptions When you’re troubleshooting someone’s problems , it becomes obvious that some of the exceptions thrown by the driver are not that helpful. In particular, it’s quite hard to understand whether it’s the server that threw an error (e.g. you’re trying to write to a secondary, which is not allowed) or the driver (e.g. can’t connect to the server, or can’t serialise that sort of Java object). So we’ve introduced the concept of Client and Server Exceptions. We’ve also introduced a lot more exceptions, so that instead of getting a MongoException with some message that you might have to parse and figure out what to do, we’re throwing specific exceptions for specific cases (for example, MongoInvalidDocumentException ). This should be helpful for anyone using the driver - whether you’re using it directly from your application, whether a third party is wrapping the driver and needs to figure out what to do in an exceptional case, or whether you’re working on the driver itself - after all, the code is open source and anyone can submit a pull request. Test Friendly The first thing I tried to do when I wrote my first MongoDB & Java application was mock the driver - while you’ll want some integration tests, you may also want to mock or stub the driver so you can test your application in isolation from MongoDB. But you can’t. All the classes are final and there are no interfaces. While there’s nothing wrong with performing system/integration/functional tests on your database, there’s often a need to test areas in isolation to have simple, fast-running tests that verify something is working as expected. The new driver makes use of interfaces at the API level so that you can mock the driver to test your application, and the cleaner, decoupled design makes it easier to create unit tests for the internals of the driver. And now, after a successful spike , we’ve started implementing Spock tests, both functional and unit, to improve the coverage and readability of the internal driver tests. In addition, we’re trying to implement more acceptance tests (which are in Java, not Groovy/Spock). The goal here is to have living documentation for the driver - not only for how to do things (“this is what an insert statement looks like”) but also to document what happens when things don’t go to plan (“this is the error you see when you pass null values in”). These tests are still very much a work in progress, but we hope to see them grow and evolve over time. Backwards Compatible Last, but by no means least, all this massive overhaul of design, architecture, and API MUST be backwards compatible. We are committed to all our existing users, we don’t want them to have to do a big bang upgrade simply to get the new and improved driver. And we believe in providing users with an upgrade path which lets them migrate gradually from the old driver, and the old API, to the new driver and new API. This has made development a little bit more tricky, but we think it’s made it easier to validate the design of the new driver - not least because we can run existing test suites against the compatible new driver (the compatible-mode driver exposes the old API but uses the new architecture), to verify that the behaviour is the same as it used to be, other than deprecated functionality . In Summary It was time for the Java Driver for MongoDB to have a bit of a facelift. To ensure a quality product, the drivers team at 10gen decided on a set of design goals for the new driver and have been hard at work creating a driver that means these criteria. In the next post, we’ll cover the new features in the 3.0 driver and show you where to find it.
MACH Aligned for Retail: Cloud-Native SaaS
MongoDB is an active member of the MACH Alliance , a non-profit cooperation of technology companies fostering the adoption of composable architecture principles promoting agility and innovation. Each letter in the MACH acronym corresponds to a different concept that should be leveraged when modernizing heritage solutions and creating brand-new experiences. MACH stands for Microservices, API-first, Cloud-native SaaS, and Headless. In previous articles in this series, we explored the importance of Microservices and the API-first approach. Here, we will focus on the third principle championed by the alliance: Cloud-native SaaS. Let’s dive in. What is cloud-native SaaS? Cloud-native SaaS solutions are vendor-managed applications developed in and for the cloud, and leveraging all the capabilities the cloud has to offer, such as fully managed hosting, built-in security, auto-scaling, cross-regional deployment, automatic updates, built-in analytics, and more. Why is cloud-native SaaS important for retail? Retailers are pressed to transform their digital offerings to meet rapidly shifting consumer needs and remain competitive. Traditionally, this means establishing areas of improvement for your systems and instructing your development teams to refactor components to introduce new capabilities (e.g., analytics engines for personalization or mobile app support) or to streamline architectures to make them easier to maintain (e.g., moving from monolith to microservices). These approaches can yield good results but require a substantial investment in time, budget, and internal technical knowledge to implement. Now, retailers have an alternative tool at their disposal: Cloud-native SaaS applications. These solutions are readily available off-the-shelf and require minimal configuration and development effort. Adopting them as part of your technology stack can accelerate the transformation and time to market of new features, while not requiring specific in-house technical expertise. Many cloud-native SaaS solutions focused on retail use cases are available (see Figure 1), including Vue Storefront , which provides a front-end presentation layer for ecommerce, and Amplience , which enables retailers to customize their digital experiences. Figure 1: Some MACH Alliance members providing retail solutions. At the same time, in-house development should not be totally discarded, and you should aim to strike the right balance between the two options based on your objectives. Figure 2 shows pros and cons of the two approaches: Figure 2: Pros and cons of cloud-native SaaS and in-house approaches. MongoDB is a great fit for cloud-native SaaS applications MongoDB’s product suite is cloud-native by design and is a great fit if your organization is adopting this principle, whether you prefer to run your database on-premises, leveraging MongoDB Community and Enterprise Advanced , or as SaaS with MongoDB Atlas . MongoDB Atlas, our developer data platform, is particularly suitable in this context. It supports the three major cloud providers (AWS, GCP, Azure) and leverages the cloud platforms’ features to achieve cloud-native principles and design: Auto-deployment & auto-healing: DB clusters are provisioned, set up, and healed automatically, reducing operational and DBA efforts. Automatically scalable: Built-in auto-scaling capabilities enable the database RAM, CPU, and storage to scale up or down depending on traffic and data volume. A MongoDB Serverless instance allows abstracting the infrastructure even further, by paying only for the resources you need. Globally distributed: The global nature of the retail industry requires data to be efficiently distributed to ensure high availability and compliance with data privacy regulations, such as GDPR , while implementing strict privacy controls. MongoDB Atlas leverages the flexibility of the cloud with its replica set architecture and multi-cloud support, meaning that data can be easily distributed to meet complex requirements Secure from the start: Network isolation, encryption, and granular auditing capabilities ensure data is only accessible to authorized individuals, thereby maintaining confidentiality. Always up to date: Security patches and minor upgrades are performed automatically with no intervention required from your team. Major releases can be integrated effortlessly, without modifying the underlying OS or working with package files. Monitorable and reliable: MongoDB Atlas distributes a set of utilities that provides real-time reporting of database activities to monitor and improve slow queries, visualize data traffic, and more. Backups are also fully managed, ensuring data integrity. Independent Software Vendors (ISVs) increasingly rely on capabilities like these to build cloud-native SaaS applications addressing retail use cases. For example, Commercetools offers a fully managed ecommerce platform underpinned by MongoDB Atlas (see Figure 3). Their end-to-end solution provides retailers with the tools to transform their ecommerce capabilities in a matter of days, instead of building a solution in-house. Commercetools is also a MACH Alliance member, fully embracing composable architecture paradigms explored in this series. Adopting Commercetools as your ecommerce platform of choice lets you automatically scale your ecommerce as traffic increases, and it integrates with many third-party systems, ranging from payment platforms to front-end solutions. Additionally, its headless nature and strong API layer allow your front-end to be adapted based on your brands, currencies, and geographies. Commercetools runs on and natively ingests data from MongoDB. Leveraging MongoDB for your other home-grown applications means that you can standardize your data estate, while taking advantage of the many capabilities that the MongoDB data platform has to offer. The same principles can be applied to other SaaS solutions running on MongoDB. Figure 3: MongoDB Atlas and Commercetools capabilities. Find out more about the MongoDB partnership with Commercetools . Learn how Commercetools enabled Audi to integrate its in-car commerce solution and adapt it to 26 countries . MongoDB supports your home-grown applications MongoDB offers a powerful developer data platform, providing the tools to leverage composable architecture patterns and build differentiating experiences in-house. The same benefits of MongoDB’s cloud-native architecture explored earlier are also applicable in this context and are leveraged by many retailers globally, such as Conrad Electronics, running their B2B ecommerce platform on MongoDB Atlas . Summary Cloud-native principles are an essential component of modern systems and applications. They support ISVs in developing powerful SaaS applications and can be leveraged to build proprietary systems in-house. In both scenarios, MongoDB is strongly positioned to deliver on the cloud-native capabilities that should be expected from a modern data platform. Stay tuned for our final blog of this series on Headless and check out our previous blogs on Microservices and API-first .