Linux PolyBase in mcr.microsoft.com/mssql/server:2025-latest only registers s3/abs/adls connectors; sqlserver://, odbc://, oracle://, mongodb://, http(s):// rejected at parser

[jamesburton]

Summary

In mcr.microsoft.com/mssql/server:2025-latest (SQL Server 2025 RTM-CU4, 17.0.4035.5) on Ubuntu 24.04 with mssql-server-polybase installed and PolyBase fully enabled, the SQL parser only accepts three LOCATION URI prefixes for CREATE EXTERNAL DATA SOURCE:

ACCEPTED:  s3://    abs://    adls://
REJECTED:  sqlserver://    odbc://    oracle://    mongodb://
           teradata://     hdfs://    wasbs://    http://    https://

All rejected schemes return error 46548 "<scheme> contains an unsupported connector location prefix. Refer to product documentation for a list of supported connector location prefixes." This is a parse-time rejection — it happens regardless of credential, server reachability, or whether the External Execution Service is running.

This contradicts the documentation at:

• create-external-data-source-transact-sql — lists sqlserver, oracle, teradata, mongodb, odbc, https, and others as supported in SQL Server 2019+.
• polybase-configure-sql-server — provides a worked sqlserver:// example.
• polybase-linux-setup — lists "SQL Server and Azure SQL" and "Oracle" / "Teradata" / "MongoDB" under "PolyBase on Linux can access the following data sources".

Reproduction

FROM mcr.microsoft.com/mssql/server:2025-latest
USER root
RUN export DEBIAN_FRONTEND=noninteractive \
    && apt-get update \
    && apt-get install -yq curl gnupg2 \
    && curl https://packages.microsoft.com/keys/microsoft.asc | apt-key add - \
    && curl https://packages.microsoft.com/config/ubuntu/24.04/mssql-server-2025.list \
         | tee /etc/apt/sources.list.d/mssql-server-2025.list \
    && curl https://packages.microsoft.com/config/ubuntu/24.04/prod.list \
         | tee /etc/apt/sources.list.d/mssql-prod.list \
    && apt-get update \
    && ACCEPT_EULA=Y apt-get install -y mssql-server-polybase mssql-tools18 unixodbc-dev
ENV MSSQL_POLYBASE_ENABLED=1
USER mssql

Run the image, wait for SQL Server ready, enable PolyBase (sp_configure 'polybase enabled', 1; RECONFIGURE WITH OVERRIDE;), restart, then run:

USE probe_db;
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'P@ssw0rd!Probe';
CREATE DATABASE SCOPED CREDENTIAL probe_cred WITH IDENTITY = 'sa', SECRET = '<sa_pwd>';

CREATE EXTERNAL DATA SOURCE probe_eds WITH (
    LOCATION = 'sqlserver://127.0.0.1:1433',
    CREDENTIAL = probe_cred);
-- Msg 46548: 'sqlserver://127.0.0.1:1433' contains an unsupported connector
--            location prefix.

What rules out the obvious causes

All of the following are true at the time of the failing CREATE — none of them change the result:

• SELECT SERVERPROPERTY('IsPolyBaseInstalled') returns 1.
• sys.configurations shows polybase enabled value_in_use = 1.
• The PolyBase Data Movement Service writes MPDWSVC is ready to its stdout log, and /var/opt/mssql/log/polybase/MSSQLSERVER_localhost_DWEngine_server.log / MSSQLSERVER_localhost_Dms_movement.log show the DW Engine and DMS fully initialised.
• .NET 8.0.18 runtime is pre-staged at /opt/mssql-ees-dotnet/ (matching the offline-install layout documented for SQL Server 2025 (17.x) CU4+).
• ExternalExecutionService.dll is started via /opt/mssql-ees-dotnet/dotnet /opt/mssql/lib/ExternalExecutionService.dll and logs ExternalExecutionService started at port 25100. (We can't use the systemd unit mssql-ees.service because Docker doesn't provide systemd, so we replicate its environment — DOTNET_ROOT, TMPDIR — and launch the daemon in the background from our entrypoint.)
• The same mssql-server-polybase package's installexecutionservice.sh requires .NET 8.0.418 (per REQUIRED_VERSION constant), but the runtime version actually shipped inside the SDK is 8.0.18. Running with the runtime alone is sufficient for the daemon to start.

With all of the above in place, only the three v2 object-storage schemes (s3://, abs://, adls://) register. Every other prefix — including https:// for Bulk Operations, which has been documented as supported since SQL Server 2017 — is rejected by the parser before any connector-level code runs.

Diagnostic SQL we used

DECLARE @r TABLE (Scheme NVARCHAR(80), Err INT, Msg NVARCHAR(2000));
DECLARE @schemes TABLE (id INT IDENTITY, s NVARCHAR(80));
INSERT INTO @schemes (s) VALUES
    ('s3://h'), ('abs://c@a.blob.core.windows.net'), ('adls://h.dfs.core.windows.net'),
    ('https://h.example.com'), ('http://h.example.com'),
    ('sqlserver://127.0.0.1'), ('sqlserver://127.0.0.1:1433'),
    ('odbc://h'), ('oracle://h:1521'), ('mongodb://h:27017');
DECLARE @s NVARCHAR(80), @i INT = 1, @max INT;
SELECT @max = MAX(id) FROM @schemes;
WHILE @i <= @max BEGIN
    SELECT @s = s FROM @schemes WHERE id = @i;
    BEGIN TRY
        EXEC ('CREATE EXTERNAL DATA SOURCE [__probe__] WITH (LOCATION = '''+@s+''', CREDENTIAL = probe_cred)');
        INSERT INTO @r VALUES (@s, 0, N'OK');
        EXEC ('DROP EXTERNAL DATA SOURCE [__probe__]');
    END TRY
    BEGIN CATCH INSERT INTO @r VALUES (@s, ERROR_NUMBER(), LEFT(ERROR_MESSAGE(), 200)); END CATCH;
    SET @i = @i + 1;
END;
SELECT * FROM @r;

Questions

1. Is this expected — i.e. has the Linux build of mssql-server-polybase for SQL Server 2025 been intentionally narrowed to v2 object-storage connectors only?
2. If yes, can the docs (polybase-linux-setup, polybase-configure-sql-server, create-external-data-source-transact-sql) be updated to reflect the actual Linux scope?
3. If no, what step is missing from the published Linux install path that would register the v1 connector schemes (sqlserver:// in particular)?
4. Is there a planned CU that will ship the v1 connectors for Linux, and if so, an approximate timeframe? The image build is now ready to register them once the package supports it (the .NET runtime and EES daemon plumbing is in place); we just need the schemes to be added to the parser's allow-list.

Happy to provide additional logs or run further diagnostics.

Environment

• Base image: mcr.microsoft.com/mssql/server:2025-latest
• SQL Server: 2025 (RTM-CU4) KB5081495 — 17.0.4035.5 Enterprise Developer Edition on Linux (Ubuntu 24.04.4 LTS)
• Package: mssql-server-polybase (latest from packages.microsoft.com/config/ubuntu/24.04/mssql-server-2025.list as of 2026-05-11)
• .NET runtime: 8.0.18 (from https://dot.net/v1/dotnet-install.sh)
• Docker: 29.3.1, Windows 11 host

[tracker1]

Just guessing, but you need to install the ODBC client adapter for any resource type you plan to connect to with polybase in the container.

[jamesburton]

Are there any instructions for adding those to the docker image to enable them?

[tracker1]

You'll have to look them up... Oracle is probably the most complex option... but each will have their own instructions for ODBC on Linux (Ubuntu)

[kakasnest]

Same issue here.

To be fair this image is shipped with msodbcsql18 (/opt/microsoft/msodbcsql18) so for odbc this should be working fine.

Given this link here you have to install the driver which would create ini files - one for the installed driver (inplace at /opt/microsoft/msodbcsql18/etc/odbcinst.ini) and one for the DSN but you should be able to opt out and simply set params in the connection string via CONNECTION_OPTIONS clause.

Therefore everything should be ready for the server to acknowledge the presence of the odbc driver. Given the docs you don't need anything else or it's not obvious to me what else should be done here besides what @jamesburton did.

[tracker1]

I'd suggest contacting Microsoft SQL Support directly... this repository is really just for supporting the base container images themselves, and even then, MS isn't really responsive here.

Assuming you have an active license for SQL Server, you should be able to file a direct support incident with them.