Error Mirroring to Fabric: The error is: Exception reading the data file.

Hi mrrozhall ,

Thank you for reaching out to Microsoft Community.

This error typically occurs when Fabric is able to detect the table schema, but cannot extract readable change data from Oracle during the initialization phase. As a result, Fabric receives an empty or non-readable result set and suspends replication with the message “Exception reading the data file. No data rows available.”

Based on similar scenarios, this is usually related to how redo/logging or storage is configured on the Oracle table rather than a datatype issue.

Common causes to validate:

Table was empty when mirroring started. Fabric expects at least one readable rowset during initialization.

SELECT COUNT(*) FROM <schema>.<table_name>;
If the count is 0, insert a temporary row, commit, then delete it and commit again to generate redo.

Table is set to NOLOGGING
NOLOGGING operations do not emit sufficient redo for mirroring.

SELECT table_name, logging
FROM all_tables
WHERE table_name = '<TABLE_NAME>';

If LOGGING = NO, enable it:
ALTER TABLE <schema>.<table_name> LOGGING;

No DML activity since table creation
If no redo was generated, LogMiner cannot capture changes. You can force redo generation with a no-op update:

UPDATE <schema>.<table_name>
SET <any_column> = <same_value>;
COMMIT;

Compression or unsupported storage attributes enabled
Certain compression settings can prevent Fabric from parsing the data blocks.

SELECT table_name, compression, compress_for
FROM dba_tables
WHERE table_name = '<TABLE_NAME>';

If compression is enabled, move the table:
ALTER TABLE <schema>.<table_name> MOVE NOCOMPRESS;

High-watermark issue (table previously emptied)
Rebuilding the segment can help:

ALTER TABLE <schema>.<table_name> MOVE; or ALTER TABLE <schema>.<table_name> SHRINK SPACE;

Supplemental logging not enabled at the database level
SELECT supplemental_log_data_min FROM v$database;
If NO, enable it:
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;

If the issue continues, please share the following so we can investigate further:

Row count of the table
Table DDL (DBMS_METADATA.GET_DDL)
Logging and compression status from DBA_TABLES

Hope this helps,
Thank you.