is microsoft.sql/services/databases connection_failed a heartbeat-based metric?

Question

is microsoft.sql/services/databases connection_failed a heartbeat-based metric?

Nina Reynolds 1 Microsoft Employee

I saw a connection_failed metric for an Azure SQL Database trigger with no service impact or failures reported in the consuming service.

is connection_failed event (only triggers if a user's connection fails) based, or heartbeat (any TCP failure from a polling service in azure monitor) based?

If it's a heartbeat, does azure monitor itself failing at the poll count as a connection error?

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Answer 1

KalyanChanumolu-MSFT 8,351

@Nina Reynolds Thank you for reaching out.

connection_failed is a platform metric. It is the Total number of Failed connections irrespective of the origin.
The consuming service could be implementing a re-try logic for handling transient connection failures.

You may want to troubleshoot further if you are seeing a high number of connection failures.
There is a limit on the maximum number of concurrent connections per SKU, beyond this limit further connections are denied and may result in failures.

We have a detailed blog post to help you troubleshoot further.

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Nina Reynolds 1 Reputation point Microsoft Employee

2021-02-24T19:39:20.25+00:00

Hi, and thank you, @KalyanChanumolu-MSFT .

The part that I don't quite understand is that our consuming service does have retry logic, but it is schedule-based, and was not accessing the service at the time... it wouldn't even have started for hours.

I figured a failed connection could be Azure Monitor polling the database and failing for a short period during some kind of cutover, but if it's just an event-based trigger for a failure from a user that isn't azure monitor, then I'm unsure of what the cause of the connection_failed was.

Would this metric trigger for a user idling in SSMS/Azure Data Studio whose computer turned off?
KalyanChanumolu-MSFT 8,351 Reputation points

2021-02-25T07:42:48.337+00:00

@Nina Reynolds Yes, the connection_failed metric is the Total number of Failed connections. These are not just from monitoring.

Just an example, if you have an open connection from SSMS and your VPN gets disconnected, the subsequent reconnection attempt would fail and would get recorded as connected_failed.

I hope this clarifies. Do let me know if you have further questions.

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is microsoft.sql/services/databases connection_failed a heartbeat-based metric?

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