This reproduces an issue where using the synchronous .Open() method to open a SqlConnection using Authentication=ActiveDirectoryManagedIdentity
take an increasingly large time when multiple connections are started in parallel.
| async | threads | totalMilliseconds |
|---|---|---|
| False | 1 | 2,584.46 |
| False | 2 | 2,787.73 |
| False | 4 | 4,301.57 |
| False | 8 | 10,845.30 |
| False | 16 | 13,047.61 |
| False | 32 | 26,729.01 |
| True | 1 | 2,020.73 |
| True | 2 | 2,098.92 |
| True | 4 | 2,208.14 |
| True | 8 | 2,176.08 |
| True | 16 | 2,230.75 |
| True | 32 | 2,384.87 |
Because I wasn't able to test Managed Identity auth locally, this requires that a SQL database and app service be deployed to Azure.
This can be done using the ./Deploy.ps1 command:
./Deploy.ps1 -SubscriptionId my-subscription-guidThe issue only affects newly opened connections, so we need to restart the app service and record the first results to get accurate numbers.
This is automated in the ./Collect.ps1 command:
./Collect.ps1 -SubscriptionId my-subscription-guid