Interested in Aiven for AlloyDB Omni but unsure if you need it? Let's compare it to PostgresSQL® and understand what it can do for your data!
Celeste Horgan
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With the introduction of Aiven for AlloyDB Omni, many of our customers have wondered what the difference is between AlloyDB Omni and its architectural source project, open source PostgreSQL®. AlloyDB Omni is more than just a re-implementation of PostgreSQL, and understanding how it is similar – and how it differs – from open source PostgreSQL is a valuable exercise.
In this article, we’ll walk through at a high level how the two compare to each other and how they differ, what level of compatibility you can expect between AlloyDB Omni and PostgreSQL, and questions to ask yourself to help you evaluate which is right for you.
This is the first article in a series about PostgreSQL-compatible databases. In future articles, we’ll cover serverless PostgreSQL variants, as well as take a look at what the open source PostgreSQL community is releasing and why it’s exciting, so stay tuned!
Before diving into AlloyDB Omni, it’s helpful to review the PostgreSQL project at a high level and understand what its characteristics are.
PostgreSQL is one of the most active and longest-running enterprise grade open source projects out there. The project became open source in 1996, making it almost 30 years old. Due to its extensive extension ecosystem and active contributor community PostgreSQL remains one of the most widely used relational databases on the planet.
PostgreSQL can be defined by a few main characteristics:
AlloyDB Omni is the containerized, freely distributed image of Google’s AlloyDB database. AlloyDB is defined as “a fully-managed, PostgreSQL-compatible database for demanding transactional workloads. It provides enterprise-grade performance and availability while maintaining 100% compatibility with open-source PostgreSQL”, per Google’s official documentation.
What this means in practice for AlloyDB Omni’s compatibility with PostgreSQL is that you can expect that any database transaction that you can make against a PostgreSQL database is one that will work against an equivalent AlloyDB Omni
At this time, Google lists no incompatibilities between AlloyDB Omni and open source PostgreSQL. Note that AlloyDB Omni follows PostgreSQL’s versioning scheme, and thus compatibility is also pinned to specific PostgreSQL versions. At the time of writing this article, the current version available of AlloyDB Omni is 15.7.0
AlloyDB Omni is fully compatible with the PostgreSQL SQL dialect, and adds additional SQL operators to manage specific kinds of data relating to columnar data processing and AI/ML workload processing. As these features do not exist in open source PostgreSQL, naturally these statements are incompatible.
Now that we understand the characteristics of PostgreSQL as a database and a bit about AlloyDB Omni, the next useful thing to do is to compare the architecture of both databases to see where they’re similar and where they’re different.
At a high level, we can divide PostgreSQL into 4 layers:
Comparing this to the AlloyDB Omni:
We see three main areas of difference in the layers previously described:
For all intents and purposes, on the back end AlloyDB and PostgreSQL are architecturally similar or the same. This is a large part of why AlloyDB can claim such high compatibility with PostgreSQL and most PostgreSQL extensions. Compared to other PostgreSQL-compatible databases, AlloyDB Omni offers the greatest architectural similarity to open source PostgreSQL, and therefore provides the least vendor lock-in.
It’s important to note that AlloyDB Omni is closed source and distributed as a Docker image. This means that ultimately, as end consumers, none of us have full transparency into the architecture of AlloyDB Omni, and thus no one can make any concrete guarantees about compatibility beyond what Google’s documentation states.
Aside from AlloyDB Omni’s significant memory management enhancements, it has two important features: enhanced ability to work with AI/ML workloads, and the ability to navigate columnar data and queries.
AlloyDB Omni’s main feature is its deep integrations for AI and ML workloads. This comes in two parts:
vector extension is an AlloyDB specific extension which adds additional vector indices to AlloyDB. Notably, the SCaNN index provides a more efficient nearest neighbors index.The second main feature that AlloyDB Omni provides is the ability to create columnar indexes and run queries against your data in a columnar fashion. This is useful for analytics use cases and other queries that run against large data sets.
We talk quite a bit about columnar data and its benefits in regards to Aiven for ClickHouse, but committing to a fully columnar database is a big decision and not the right move for many businesses. The columnar engine in AlloyDB Omni is a great transition for anyone with existing Postgres databases who wants to explore whether columnar queries are more efficient for their use case.
While it may seem that AlloyDB Omni offers everything PostgreSQL does and more, there’s a use case for both technologies in a modern data stack.
Aiven for AlloyDB Omni is best for those who…
Whereas Aiven for PostgreSQL is best for those who…
In the end, it’s all about what you intend to do with your data, and how portable you need your data to be in future. If you need more information, we encourage you to book a demo for AlloyDB Omni and Postgres, and discuss with our sales team which technology benefits you the most.
Aiven for AlloyDB Omni is now available and is a fully managed AlloyDB Omni database deployable on Google Cloud, Amazon AWS and Microsoft Azure cloud platforms. It provides the benefits of an AlloyDB database, the stability of a managed service, and the flexibility to deploy to any major cloud provider. Sign up today to create your AlloyDB Omni instance.