Mirroring Oracle limitations in Microsoft Fabric

This article outlines the current limits when mirroring Oracle databases in Microsoft Fabric. These limits could change as we continue to improve the service.

Scale Limits

Here's what you can expect for database scale:

• Currently, mirrored database supports up to 500 tables
• In each workspace, you can have:
  • One Oracle server
  • One On-Premises Data Gateway (OPDG) instance
  • One Oracle mirror artifact

Supported Environments

We support these Oracle Server environments:

• Oracle versions 11 and above with LogMiner enabled
• Oracle on-premises (VM, Azure VM)
• Oracle Cloud Infrastructure (OCI)
• Oracle Exadata

Mirroring prerequisites

Here's what you need for your database setup:

• A Microsoft Fabric workspace with Trial or Premium Fabric capacity
• Install the latest On-Premises Data Gateway (August 2025). Learn how to install and register a gateway and connect the gateway to your Fabric workspace

Data Types and Schema Support

These Oracle data types are supported:

• VARCHAR2
• NVARCHAR2
• NUMBER
• FLOAT
• DATE
• BINARY_FLOAT
• BINARY_DOUBLE
• RAW
• ROWID
• CHAR
• NCHAR
• TIMESTAMP WITH LOCAL TIME ZONE
• INTERVAL DAY TO SECOND
• INTERVAL YEAR TO MONTH

For schema (DDL) changes, we currently support:

• Column changes (partial support):
  • Add columns
  • Delete columns
  • Rename columns

Currently, tables that do not have a Primary Key (PK) are not supported.

We cannot support table names that have a length greater than or equal to 30.

Required Permissions

Your sync user needs these permissions:

GRANT CREATE SESSION TO user;
GRANT SELECT_CATALOG_ROLE TO user;
GRANT CONNECT, RESOURCE TO user;
GRANT EXECUTE_CATALOG_ROLE TO user;
GRANT FLASHBACK ANY TABLE TO user;
GRANT SELECT ANY DICTIONARY TO user;
GRANT SELECT ANY TABLE TO user;
GRANT LOGMINING TO user;

Configuration Requirements

Archive Log Settings

Your database needs these archive log settings:

• ARCHIVELOG mode enabled
• Keep archive log mode on during mirroring
• Redo log file archiving enabled by the database admin

Logging Configuration

If your Oracle user doesn't have direct ALTER DATABASE and ALTER TABLE permissions, ask your DBA to run these commands:

1. Enable supplemental logging for the database:

   ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;
   ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY, UNIQUE) COLUMNS;
   

2. Enable supplemental logging for each table you want to mirror:

   ALTER TABLE {schemaName}.{tableName} ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;
   

Set up your gateway

Currently, we only support connecting to Oracle using an On-Premises Data Gateway (OPDG). You need to install and configure the gateway on a machine that can connect to your Oracle server.

For machine requirements and setup instructions to install and register your gateway, see the On-premises Data Gateway installation guide.

Related Content

• Mirror Oracle databases in Microsoft Fabric
• Set up Oracle database mirroring