I have a SQL Managed Instance (General Purpose Gen5 (256 GB, 4 vCores). I want to know if this database has a "Cold Start" delay on the first query after some idle time. If so, How can this be prevented. It sometimes takes over 1 1/2 minutes to return the first query after some period of inactivity. After that first query request comes back in seconds. In my setup I have an AppServce API making calls to the SQL Managed Instance. We need to find a way to keep the database alive and responsive at all times. Is this possible. If so how would I do it? Thanks, Scott Witherell

Hi Scott We did check the policy regarding Cold Start with our product group(PG) team and conveyed this should be inspected. They have suggested to open a support ticket which will be either resolved by CSS team or escalated to PG on-call engineers. Please do raise the same which will provide insight into your Azure resources and share the SR number so that we can follow up with them to expedite the SR. Thanks Navtej S

Azure SQL Managed Instance - General Purpose Gen5 (256 GB, 4 vCores) Cold Start Delay

Accepted answer

Navtej Singh Saini 4,221 Reputation points Microsoft Employee

2020-06-04T21:37:34.317+00:00

Hi Scott

We did check the policy regarding Cold Start with our product group(PG) team and conveyed this should be inspected.

They have suggested to open a support ticket which will be either resolved by CSS team or escalated to PG on-call engineers.

Please do raise the same which will provide insight into your Azure resources and share the SR number so that we can follow up with them to expedite the SR.

Thanks
Navtej S
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WITHERELL Scott 21 Reputation points

2020-06-04T22:05:54.023+00:00

The SR is 120060124008247

Ronen Ariely 15,096 Reputation points

2020-06-05T04:32:36.717+00:00

hi @WITHERELL Scott ,

Obviously opening a ticket will let the team the option to examine the specific subscription and track any issue if exists in the Azure side...

With that being said, the issue sound very common and i had multiple (tans) or calls from clients about the same issue without any relation to Azure Managed Instance but with all type of databases. The issue which is familiar to me and fit the description is in the application side. Meaning it is not the database that "sleep" but the service of the application (for example the IIS) which sleep

I see no point in your description which point to an issue in the database. Please confirm that this happen if you try to connect to the database using SSMS or only when you use your application. My guess at this time (without any base) is the the issue is not related to the Azure SQL Database but to the application - in this case we can solve it fast (probably)

Ronen Ariely 15,096 Reputation points

2020-06-05T04:33:02.957+00:00

For example IIS has built-in configuration to make the Application Pool alive: Open IIS Manager and browse to Application Pools. Right-click on a particular Application Pool and click Advanced Settings. In the "Process Model" section, change "Idle Time-out (mintues)" to a value of your choice. A value of 0 will disable the timeout.

WITHERELL Scott 21 Reputation points

2020-06-05T19:40:10.623+00:00

This is a Azure SQL Managed Instance. I don't think IIS is involved at all. This is a PaaS.

Ronen Ariely 15,096 Reputation points

2020-06-05T21:23:12.413+00:00

according to your description you use your application "I have an AppServce API making calls to the SQL Managed Instance."

You can check if this related to the app in 2 seconds but until you clarify that it is not, your description it does not clear if you notice this issue only when you use your application. It is not clear if the issue exits only when you use your application.

If the issue only happen when you use your application then this is probably an issue in the your internal configuration and has nothing to do with the database

To confirm this, as I wrote above you simply need to connect the database directly using someone else application like using the SSMS. If this issue does not happen when you use the SSMS then this is probably related to your side.

Again, you can confirm it in 2 second 😀as I wrote above:

Please confirm that this happen if you try to connect to the database using SSMS or only when you use your application.

Scott Witherell 1 Reputation point

2020-06-05T21:33:46.623+00:00

do have a ticket open. And you are correct that the delay does not seem to be the database itself. It is true that if I hit the database with SSMS there is no initial delay. If I make a call the the App Service API that does not need to hit the database the response is instant. The slowness seems to be mostly after inactivity for 15 minutes or so and then calling the API with something that does hit the database. It seems like it might be something to do with networking in Azure between the App Service and SQL Managed Instance. We have a MS network engineer assigned to our case now and I am hoping to speak with them soon.
Thanks for the reply,

Navtej Singh Saini 4,221 Reputation points Microsoft Employee

2020-06-08T17:30:00.26+00:00

Thanks for sharing. Checking more regarding this.
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Azure SQL Managed Instance - General Purpose Gen5 (256 GB, 4 vCores) Cold Start Delay

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