Microsoft SQL Server has been a cornerstone relational database for decades, powering enterprise workloads across finance, retail, healthcare, and many other industries. With its strong tooling ecosystem and robust feature set, SQL Server has long been a preferred choice for transactional systems. However, the database landscape has evolved rapidly. The need for distributed architectures, cloud-native design, and horizontal scalability has driven organizations to explore modern alternatives. This is why we started our ongoing series on modernizing legacy databases to a scalable distributed database architecture, you can also read our previous blog on migrating Schema from Oracle to YugabyteDB using HexaRocket. In this article, we will witness our observations on migrating SQL Server workloads to YugabyteDB, using HexaRocket.
Our objective, once more, is to evaluate whether a tool such as HexaRocket can treat YugabyteDB as a PostgreSQL-compatible system and still deliver a 100% accurate schema conversion and deployment.
YugabyteDB - an open-source, PostgreSQL-compatible distributed SQL database - has emerged as one of the strongest options for enterprises looking to modernize. Since YugabyteDB maintains PostgreSQL compatibility at the YSQL API layer, most PostgreSQL tooling can be applied directly, including schema migration tools like HexaRocket. Our intention again is to see if a tool like HexaRocket, can accept YugabyteDB as if it is talking to PostgreSQL, and still accomplish a 100% successful schema conversion and deployment.
We were curious to test how seamlessly HexaRocket could migrate a SQL Server schema to YugabyteDB, treating YugabyteDB as a PostgreSQL-compatible target. Below is what we found during this evaluation.
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Try Today!SQL Server remains a powerful database engine supporting highly critical OLTP and analytical workloads. However, as organizations scale out globally - and as cloud costs grow - many teams face challenges such as -
This is why a growing number of enterprises are evaluating open-source or open-core distributed SQL databases such as PostgreSQL or PostgreSQL-compatible platforms like YugabyteDB.
YugabyteDB offers -
One of YugabyteDB’s biggest advantages is its deep PostgreSQL compatibility. Its YSQL layer is wire-compatible and syntax-compatible with PostgreSQL, which means -
For detailed PostgreSQL compatibility notes, visit Yugabyte YSQL Compatibility Reference.
This makes migration from SQL Server to YugabyteDB easier using tools already optimized for PostgreSQL compatibility - such as HexaRocket.
Microsoft SQL Server has been a reliable and widely adopted choice for enterprise-grade transactional and analytical workloads for decades. However, challenges such as high licensing costs, limited horizontal scalability, and increasing concerns around vendor lock-in have prompted many organizations to consider open-source or open-core alternatives like PostgreSQL and PostgreSQL-compatible distributed databases such as YugabyteDB.
When planning a migration, automation, accuracy, and compatibility become crucial. This is where HexaRocket plays a significant role, simplifying the schema translation process and accelerating the journey from SQL Server to YugabyteDB. HexaRocket also supports data migration and cdc for replication from SQL Server to YugabyteDB, but that report will be considered in a future article. We are currently limiting this article to Schema conversion only.
HexaRocket is a unified database migration (Schema migration, Data migration) and replication engine (supports CDC) developed by HexaCluster to support multiple migration paths including -
Additionally, HexaRocket supports Data Migration and CDC (real-time replication) across -
While HexaRocket was not built on top of SQL Server migration tools like SQL Server Migration Assistant (SSMA), we have incorporated years of learning from heterogeneous database migrations. For converting T-SQL code to PostgreSQL-compatible PL/pgSQL, we designed advanced code parsers and validation-driven workflows that enable highly accurate and near-fully automated schema conversions.
Since YugabyteDB is PostgreSQL-compatible, HexaRocket connects to it just like a standard PostgreSQL database. In our tests, HexaRocket achieved a 100% success rate in migrating SQL Server schemas to YugabyteDB on the first attempt - with no manual code edits, adjustments, or post-migration fixes required.
Our aim was to test schema migration involving Tables of almost all data types supported by SQL Server, and some of the code objects like Stored Procedures, Functions, and also Views.
Overall, we have included 2161 Objects that cover a good amount of complexity.
The result was originally expected to be nearly 100%, reflecting our confidence in YugaByteDB's full PostgreSQL compatibility. As expected, we see all objects migrated and also deployed to YugabyteDB without any adjustments.
As we witness in the "Migration Overview" dashboard of HexaRocket, we see all the 2,161 object migrated successfully.
What this means is that all the Tables, Constraints, Indexes, Sequences, User Defined Types, Views, Stored Procedures, Functions and Triggers have all been migrated and also deployed successfully.
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Now, let us take a deeper look at the datatype mapping between SQL Server and Yugabyte. Please note that the Yugabyte official documentation states that some of the datatypes are still being adopted. In case of any typos made or mistakes done during this draft, please notify us and we could correct the same.
You may see that some of the data types are unsupported or do not have any direct alternatives. However, based on our experience in migrations for the past 2 decades, we can say that they are some of the most rarely observed types. We can still use work-arounds to manage such unsupported types, based on the discussions with Application Architects and Developers.
| SQL Server | Yugabyte | Status |
|---|---|---|
| tinyint | SMALLINT | Supported |
| smallint | SMALLINT | Supported |
| int | INT | Supported |
| bigint | BIGINT | Supported |
| bit | BOOLEAN | Supported |
| decimal | NUMERIC | Supported |
| numeric | NUMERIC | Supported |
| money | NUMERIC | Supported |
| smallmoney | NUMERIC | Supported |
| float | DOUBLE PRECISION / FLOAT | Supported |
| real | REAL | Supported |
| date | DATE | Supported |
| time | TIME | Supported |
| datetime2 | TIMESTAMP (without time zone / with precision) | Supported |
| datetimeoffset | TIMESTAMPTZ (timestamp with time zone) | Partially supported |
| datetime | TIMESTAMP | Supported |
| smalldatetime | TIMESTAMP | Partially supported |
| char | CHAR | Supported |
| varchar | VARCHAR | Supported |
| varchar(max) | TEXT | Supported |
| text (deprecated) | TEXT | Supported |
| nchar | CHAR (YSQL stores UTF-8) | Supported |
| nvarchar | VARCHAR (UTF-8) | Supported |
| nvarchar(max) | TEXT | Supported |
| ntext (deprecated) | TEXT | Supported |
| binary | BYTEA | Supported |
| varbinary | BYTEA | Supported |
| varbinary(max) | BYTEA | Supported |
| image (deprecated) | BYTEA | Supported |
| rowversion / timestamp | BYTEA (or numeric surrogate) | Partially supported |
| uniqueidentifier | UUID | Supported |
| xml | XML | Supported |
| sql_variant | - | Not Supported |
| hierarchyid | - | Not Supported |
| geography (spatial) | geometry/geography (PostGIS) | Partially supported |
| geometry (spatial) | geometry/geography (PostGIS) | Partially supported |
HexaRocket not only simplifies database migrations to PostgreSQL, but also to PostgreSQL Compatible databases. Be it PostgreSQL or YugabyteDB, you can simply migrate your SQL Server, and other databases to YugabyteDB seamlessly.
In our next article, we will talk about our observations on data migration and CDC from SQL Server to Yugabyte. And then, we shall present you with some interesting facts about MySQL and MariaDB to YugabyteDB. This is because HexaRocket supports end-to-end database migrations from Oracle, SQL Server, MySQL, and MariaDB to PostgreSQL, so naturally expected to support YugabyteDB.
Explore our services at Database migrations to PostgreSQL. Remember, it is not just about Database Migrations, we also provide Consulting services for performing Application Migrations and Modernizations.
The authors of this article are also the creators of HexaRocket schema migration engine that simplifies schema migration from any database to any database. Your input and feedback are greatly valuable, and it directly reaches the authors.
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Babasai is a Senior Developer at HexaCluster with strong background in Backend and Front-end technology stack. Babasai has strong expertise in various technologies like Java, Golang, C, C++, and Databases like PostgreSQL, Oracle, SQL Server, MySQL and MariaDB. Babasai's expertise has helped multiple customers modernize their Technology stack from legacy to an advanced Open-Source technology stack. Additionally, the expertise of Babasai has helped the customers of HexaRocket seamlessly migrate their schema between any databases.
Sai is an expert developer at HexaCluster with highest level of expertise in both Backend and Frontend technology stack. His ability to research and implementation at scale has not only helped customers transform their applications but also implement latest advanced technologies meeting enterprise standards. His ability to research and understanding of database internals, has enabled HexaRocket to achieve seamless schema migration capabilities between multiple databases. His expertise includes Java, Golang, C, C++, React, JavaScript, with deep understand of Oracle, PostgreSQL, SQL Server, MySQL, MariaDB and BigQuery internals.
Anil is a Senior developer at HexaCluster. Anil worked on many critical development projects and gained huge accolades from his Customers each time. He is a full-stack developer with expertise in both front-end and backend technology stack. With strong expertise in database design, design patterns, Java, Golang, React and many other popular technologies, Anil has done great contributions to HexaRocket to simplify database migrations between multiple databases.
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