Best Relational Databases with Open source Capabilities

Amazon Relational Database Service (Amazon RDS) makes it easy to set up, operate, and scale a relational database in the cloud. It provides cost-efficient and resizable capacity while managing time-consuming database administration tasks such as hardware provisioning, database setup, patching and backups. It frees you up to focus on your apps so you can give them the better performance, availability, security, and compatibility they need. Amazon RDS is available on 6 familiar database instances: Amazon Aurora, MySQL, PostgreSQL, MariaDB, Oracle Database and SQL Server engines. This means that the code, applications, and tools you already use today with your existing databases can be used with Amazon RDS. Amazon RDS automatically patches the database software and backs up your database, storing the backups for a user-defined retention period and enabling point-in-time recovery. You benefit from the flexibility of being able to scale the compute resources or storage capacity associated with your relational database instance via a single API call. In addition, Amazon RDS makes it easy to use replication to enhance availability and reliability for production databases. Amazon RDS for MySQL also enables you to scale out beyond the capacity of a single database deployment for read-heavy database workloads. As with all Amazon Web Services, there are no up-front investments required, and you pay only for the resources you use.

MySQL is an open source database solution.

PostgreSQL is a powerful, open source object-relational database system.

With SAP® Adaptive Server® Enterprise (SAP ASE), you can handle massive volumes of data and thousands of concurrent users to accelerate the growth of new data-driven business applications. Drive value with a faster, more efficient transactional system that is designed to meet the demands of the digital economy.

YugabyteDB is turbocharged PostgreSQL for business-critical transactional applications. 100% open source, it offers built-in resilience, on-demand scaling, and more! YugabyteDB eliminates the tradeoffs you must make with legacy databases by uniquely combining enterprise-grade RDBMS capabilities with the horizontal scalability and resilience of cloud native architectures. YugabyteDB delivers a single logical database that can span across any cloud—private, public or hybrid. Industry-leading companies such as Kroger, GM, Rakuten, Fiserv and Wells Fargo rely on YugabyteDB for mission-critical transactional applications because of key capabilities: PostgreSQL Compatibility YugabyteDB is more than just wire compatible with PostgreSQL, it is code compatible. YugabyteDB achieves this by reusing PostgreSQL’s query layer to achieve a high degree of compatibility with existing PostgreSQL applications or those that can be migrated to PostgreSQL. Developers can be immediately productive with the ecosystem of PostgreSQL compatible frameworks, applications, drivers, and tools. Advanced Relational Database Capabilities YugabyteDB delivers a comprehensive set of advanced RDBMS features like triggers, functions, stored procedures, strong secondary indexes, and distributed ACID transactions. This means that developers no longer need to choose between the horizontal scalability of NoSQL systems and the ACID guarantees of traditional SQL systems. Resilience and High Availability With YugabyteDB, critical services can remain available during node, zone, region, and data center failures with fast failovers. YugabyteDB heals itself by re-replicating data automatically, and delivers zero downtime on maintenance tasks such as software upgrades, security patching, and distributed backups. Horizontal Scalability Operations teams can effortlessly scale out even under heavy load without disruption or downtime by simply adding nodes to their YugabyteDB cluster. The database automatically rebalances load to use available resources. YugabyteDB’s shared nothing architecture is designed with no single point of failure or bottleneck. Geographic Distribution YugabyteDB offers the most comprehensive and flexible deployment options in geo-distributed environments. Operators can make use of synchronous and asynchronous data replication and geo-partitioning to achieve desired consistency, resilience, performance, and compliance objectives. Security YugabyteDB is built from the ground up with data security in mind. The database enables organizations to maintain a robust security posture with built-in controls such as LDAP authentication, role-based access control (RBAC), data encryption at rest and in transit (TLS), audit logging, and column-level permissions. You can also get advanced features such as row level security (RLS) and column-level encryption for more advanced use cases. Download and start using the full set of features for free as a 100% open source solution, or choose one of the other flexible cloud DBaaS consumption options based on your needs: 1. YugabyteDB Aeon: Start with a free trial and enjoy a fully-managed DBaaS service that allows you to leave the day 2 operations and management work to Yugabyte. 2. YugabyteDB Anywhere: Deploy a self-managed DBaaS in your environment with built-in automation to deploy, scale, and monitor YugabyteDB clusters at scale. And YugabyteDB Voyager is a new end-to-end migration tool that can accelerate your cloud native adoption by simplifying the migration of both schema and data from databases like Oracle, PostgreSQL, mySQL, Aurora PostgreSQL, Azure SQL for PostgreSQL, and more. Learn more about Yugabyte products here: https://www.yugabyte.com/ Sign up for YugabyteDB Aeon for free here: https://cloud.yugabyte.com/

MariaDB frees companies from the costs, constraints and complexity of proprietary databases, enabling them to reinvest in what matters most – rapidly developing innovative, customer-facing applications. MariaDB uses pluggable, purpose-built storage engines to support workloads that previously required a variety of specialized databases. With complexity and constraints eliminated, enterprises can now depend on a single complete database for all their needs, whether on commodity hardware or their cloud of choice. Deployed in minutes for transactional or analytical use cases, MariaDB delivers unmatched operational agility without sacrificing key enterprise features including real ACID compliance and full SQL. Trusted by organizations such as Deutsche Bank, DBS Bank, Nasdaq, Red Hat, ServiceNow, Verizon and Walgreens – MariaDB meets the same core requirements as proprietary databases at a fraction of the cost. No wonder it’s the fastest growing open source database. Real business relies on MariaDB™.

SQLite is a software library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine

Aiven for PostgreSQL is a fully managed, scalable PostgreSQL service. It is full-featured, and backed by a 99.99% SLA. You can launch a fully operational PostgreSQL cluster in the cloud and region of your choice in minutes - using the Aiven web console or programmatically via Aiven’s API, CLI, Terraform provider or Kubernetes operator. You'll have access to premium features, such as Point in Time Restore, database forking, connection pooling, and more. And you can use over 70 PostgreSQL extensions. With Aiven for PostgreSQL, you don’t need to worry about taking backups or applying maintenance updates. All this is done automatically - with no downtime. You can upgrade to a new version, increase the storage of your cluster, expand to new regions or migrate to a different cloud, with a click of a mouse. Data is encrypted at rest and in transit, and clusters are always run on dedicated virtual machines. The service is ISO27001, SOC 2, HIPAA, GDPR, CCPA and PCI/DSS compliant.

Overview Cockroach Labs is the creator of CockroachDB, the cloud-native, resilient, distributed SQL database enterprises worldwide trust to run mission-critical AI and other applications that scale fast, avert and survive disaster, and thrive everywhere. It runs on the Big 3 clouds, on prem, and in hybrid configurations powering Fortune 500, Forbes Global 2000, and Inc. 5000 brands, and game-changing innovators, including OpenAI, CoreWeave, Adobe, NETFLIX, Booking.com, DoorDash, FANDUEL, Cisco Systems, P&G, UiPath, FORTINET, Roblox, EA, BestBuy, SpaceX, NVIDIA, The VA, Squarespace, The Home Depot, and Hewlett Packard Enterprise. Cockroach Labs has customers in 40+ countries across all world regions, 25+ verticals, and 50+ Use Cases. Cockroach Labs operates its own ISV Partner Ecosystem powering Payments, Identity Management (IDM/IAM), Banking & Wallet, Trading, and other high-demand use cases. Cockroach Labs is an AWS Partner of the Year finalist and has achieved AWS Competency Partner certifications in Data & Analytics and Financial Services (FSI). CockroachDB pricing is available at https://www.cockroachlabs.com/pricing/ Vector, RAG, and GenAI Workloads CockroachDB includes native support for the VECTOR data type and pgvector API compatibility, enabling storage and retrieval of high-dimensional embeddings. These vector capabilities are critical for Retrieval-Augmented Generation (RAG) pipelines and GenAI workloads that rely on similarity search and contextual embeddings. By supporting distributed vector indexing within the database itself, CockroachDB removes the need for external vector stores and allows AI applications to operate against a single, consistent data layer. C-SPANN Distributed Indexing At the core of CockroachDB’s vector search capabilities is the C-SPANN indexing engine. C-SPANN provides scalable approximate nearest neighbor (ANN) search across billions of vectors while supporting incremental updates, real-time writes, and partitioned indexing. This ensures low-latency retrieval in the tens of milliseconds, even under high query throughput. The algorithm eliminates central coordinators, avoids large in-memory structures, and leverages CockroachDB’s sharding and replication to deliver scale, resilience, and global consistency. Machine Learning and Apache Spark Integration CockroachDB integrates with modern ML workflows by supporting embeddings generated through frameworks such as AWS Bedrock and Google Vertex AI. Its compatibility with the PostgreSQL JDBC driver allows seamless integration with Apache Spark, enabling distributed processing and advanced analytics on CockroachDB data. PostgreSQL Compatibility and JSON Support CockroachDB speaks the PostgreSQL wire protocol, so applications, drivers, and tools designed to work with Postgres can connect to CockroachDB without modification, enabling seamless use of familiar SQL features and integration with the wider Postgres ecosystem. This includes support for advanced data types such as JSON and JSONB, which allow developers to store and query semi-structured data natively. Geospatial and Graph Capabilities CockroachDB also provides first-class geospatial data support, allowing developers to store, query, and analyze spatial data directly in SQL. For graph workloads, CockroachDB employs JSON flexibility to represent relationships and delivers query capabilities for graph-like traversals. This combination enables hybrid applications that merge relational, geospatial, document, and graph data within a single platform. Analytics, BI, and Integration To support high-performance analytics and BI, CockroachDB supports core analytical use cases and functions including Enterprise Data Warehouse, Lakehouse, and Event Analytics, and offers materialized views for precomputing complex joins and aggregations. Its PostgreSQL wire compatibility ensures direct connectivity with all relevant BI and analytics apps and tools including Amazon Redshift, Snowflake, Kafka, Google BigQuery, Salesforce Tableau, Databricks, Cognos, Looker, Grafana, Power BI, Qlik Sense, SAP, SAS, Sisense, and TIBCO Spotfire. Data scientists can interact with CockroachDB through Jupyter Notebooks, querying structured and semi-structured data and loading results for analysis. Change data capture (CDC) streams provide real-time updates to analytics pipelines and feature stores, keeping downstream systems fresh and reliable. Columnar vectorized execution accelerates query processing, optimizes transactional throughput, and minimizes latency for demanding distributed workloads. MOLT AI-Powered Migration Organizations often know their data infrastructure is not supporting the business, but find it too painful to change. CockroachDB’s MOLT (Migrate Off Legacy Technology) is designed to enable safe, minimal-downtime database migrations from legacy systems to CockroachDB. MOLT Fetch supports data migration from PostgreSQL, MySQL, SQL Server, and Oracle, with SQL Server and DB2 coming soon. CockroachDB also has a portfolio of data replication platform integrations including Precisely, Striim, Qlik, Confluent, IBM, etc. Together, these capabilities ensure that CockroachDB supports both operational and analytical workloads, bridging traditional SQL applications with emerging Gen AI and ML use cases.

Citus Data horizontally scales PostgreSQL, taking relational power further for real-time data.

Apache Derby is a relational database management system developed by the Apache Software Foundation that can be embedded in Java programs and used for online transaction processing.

Firebird is a relational database offering many ANSI SQL standard features that runs on Linux, Windows, and a variety of Unix platforms.

Distributed SQL Query Engine for Big Data

Apache Druid is an open source real-time analytics database. Druid combines ideas from OLAP/analytic databases, timeseries databases, and search systems to create a complete real-time analytics solution for real-time data. It includes stream and batch ingestion, column-oriented storage, time-optimized partitioning, native OLAP and search indexing, SQL and REST support, flexible schemas; all with true horizontal scalability on a shared nothing, cloud native architecture that makes it easy to deploy, monitor and manage at scale. It is downloadable for free for unlimited use from druid.apache.org and also hosted in the cloud by Imply Data.

CitrusDB is a massively scalable PostgreSQL database for real-time applications.