Azure SQL Database Mirroring High Latency

[kent-lee]

We have been experiencing significant delays in our mirrored database. While the initial load has no issue, over time, some tables become outdated. The latency can extend up to several days when comparing the data in our Fabric mirrored database to the source database. Additionally, there is a substantial row count discrepancy between the reported numbers in "Monitor replication" versus the actual row counts in Fabric.

Our setup:

• We are mirroring 7 tables from Azure SQL Managed Instance.
• 4 tables are small, each containing fewer than 1 million rows.
• The largest table contains 4.2 million rows.
• We have confirmed that the source system resource is not a bottleneck, as the DTU usage has never exceeded 50%.
• We followed the troubleshooting steps outlined in https://learn.microsoft.com/en-us/fabric/database/mirrored-database/azure-sql-database-troubleshoot and found no errors.
• We tried restarting the database mirroring but we encounter the same issues.

Issues:

• All tables have some degree of delay. We noticed this by comparing (1) the last modified time column values between source database and Fabric, and (2), the row counts between those specified in "Monitor replication" and Fabric tables.
• The most severely affected table shows over 3 hours of delay and a row count discrepancy of over 1 million, with these numbers increasing over time. And it is always this table that gets affected the most, even after restarting the database replication.

We are seeking support to resolve these issues. Thank you.

[kent-lee]

Hello @Anonymous,

Thank you for the quick response. Support request number: 2406050040006934

[Anonymous]

Hi @kent-lee ,

You are welcome. Thanks for sharing the support ticket.

Please allow some time, so team can check and provide a resolution.

In case if you got a resolution please do share with the community as it can be helpful to others 

[Anonymous]

Hi @kent-lee ,

Apologize for the issue you are facing. The best course of action is to open a support ticket and have our support team take a closer look at it.

Please reach out to our support team so they can do a more thorough investigation on why this it is happening: Link 

After creating a Support ticket please provide the ticket number as it would help us to track for more information.

Hope this helps. Please let us know if you have any other queries.