Data load to the managed sql instance is taking forever, DB server is not responding and there is time out error also

The timeout error you are experiencing during data load to the managed SQL instance indicates that the operation is taking longer than the allowed time period. This can happen for several reasons, including server unresponsiveness or network issues. Here are some steps you can take to troubleshoot and resolve the issue:

1. Increase the Command Timeout: If you are using an application to connect to SQL Server, consider increasing the command timeout setting. For example, in .NET applications, you can set the SqlCommand.CommandTimeout property to a higher value than the default (which is typically 30 seconds).
2. Check Server Performance: Ensure that the SQL Server instance is not under heavy load. High CPU usage, memory pressure, or disk I/O issues can lead to timeouts. You may need to monitor the server's performance metrics to identify any bottlenecks.
3. Review Network Connectivity: If the server is unresponsive, check the network connection between your application and the SQL Server. Network latency or interruptions can cause timeouts. Work with your network administrator to resolve any connectivity issues.
4. Optimize Queries: If the timeout occurs during query execution, review the queries being executed for optimization opportunities. Long-running queries can lead to timeouts, especially if they are not properly indexed.
5. Connection Pooling: Ensure that connections are being closed properly in your application. If connections are not released back to the pool, it can exhaust the available connections and lead to timeouts.
6. Consult SQL Server Logs: Check the SQL Server error logs for any related messages that might provide additional context on the timeout errors.

By following these steps, you should be able to identify the cause of the timeout and take appropriate actions to resolve it.

References:

• Timeout expired messages when connecting to SQL Server
• Troubleshoot query time-out errors
• Troubleshoot connectivity issues and other errors

Hi Anand Kishore,
Thank you for reaching out to Microsoft QA!
It sounds like you're facing a tough situation with your managed SQL instance where the data load is taking a long time, and you're encountering timeout errors. Here’s a bit of guidance on what you can do to troubleshoot this issue:

First, rule out blocking sessions:

Fire up a query in SSMS like SELECT * FROM sys.dm_exec_requests CROSS APPLY sys.dm_exec_sql_text(sql_handle) WHERE blocking_session_id <> 0 to spot any long-running transactions holding locks commit or kill them if they're stuck. Open sessions can totally choke your data load.​

Bump those timeouts and check connections:

In your ADF sink settings, crank the write batch timeout (try 00:30:00) and connection timeout to 30+ seconds. If you're scripting this via CLI/PowerShell, throw in -AsJob for long hauls so it doesn't bail early.​

Permissions quick check:

Confirm your service principal or managed identity has SQL Managed Instance Contributor role at the resource group or sub level that covers networking and instance management without overkill.​

Service health and limits:

Peek at Azure Service Health or Resource Health dashboard for any MI outages or degradations. Also scan your instance metrics for CPU/IO maxing out per your service tier (e.g., vCore limits) scale up temporarily if it's pegged.​

Extra diagnostics tips:

Grab the latest SSMS (v20+ now), run connection diagnostics from the Azure portal, and review known issues docs for MI-specific gotchas. Test a small batch first to isolate.​

That should get you unblocked let me know what the blocking query shows!
What specific operation were you trying to perform when the timeout occurred?

Have you checked the SQL Server logs for any detailed errors or messages related to the timeout?

What size is the database, and are there any specific configurations or constraints placed on it (like resource limits)?

Are there other workloads running on the managed instance that may be affecting performance?

Hope this helps you troubleshoot the issue! If you have any more details or need further assistance, just let me know!