Use Singleton Metrics Provider for Listener #285
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src/DurableTask.SqlServer.AzureFunctions/SqlDurabilityProvider.cs
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src/DurableTask.SqlServer.AzureFunctions/SqlDurabilityProvider.cs
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| { | ||
| this.sqlMetricsProvider = sqlMetricsProvider; | ||
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| // Scalers in Durable Functions are shared for all functions in the same task hub. | ||
| // So instead of using a function ID, we use the task hub name as the basis for the descriptor ID. | ||
| string id = $"DurableTask-SqlServer:{taskHubName ?? "default"}"; |
| { | ||
| // Scalers in Durable Functions are shared for all functions in the same task hub. | ||
| // So instead of using a function ID, we use the task hub name as the basis for the descriptor ID. | ||
| // Scalers in Durable Functions is per function ids. And scalers share the same sqlMetricsProvider in the same taskhub. | ||
| string id = $"DurableTask-SqlServer:{taskHubName ?? "default"}"; |
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| string id = $"DurableTask-SqlServer:{taskHubName ?? "default"}"; | |
| string id = $"{functionId}-DurableTask-SqlServer:{taskHubName ?? "default"}"; |
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Thanks! does this string id needs to add ToLower(CultureInfo.InvariantCulture) to be lower case?
| { | ||
| var sqlMetricsProvider = new SqlMetricsProvider(this.service); | ||
| this.scaleMonitor = new SqlScaleMonitor(hubName, sqlMetricsProvider); | ||
| this.singletonSqlMetricsProvider = new SqlMetricsProvider(this.service); |
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One last thing. I recall the final fix that Alexey made to the Azure Storage metrics provider was to throttle it so that we only fetch metrics once every few seconds or so. This is how we ensured that we don't have too many storage transactions, even if the app has a lot of triggers. I think it will be important to do that for the SqlMetricsProvider too so that we don't overwhelm the customer's database with expensive SQL queries.
| using System.Threading; | ||
| using System.Threading.Tasks; | ||
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| public class SqlMetricsProvider | ||
| { | ||
| readonly SqlOrchestrationService service; | ||
| DateTime metricsTimeStamp = DateTime.MinValue; | ||
| SqlScaleMetric? metrics; |
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Added this cache. If the target scaler calls GetMetricsAsync within 5 seconds, return the last result to make sure the target scaler remains the same decision as last time.
Similar changes at AzureStorage backend Azure/azure-functions-durable-extension@c5d8e04#diff-09935cd15a9926e82e0d7ff3df8d480813cabd51b8e3a483985ec5a0da3035cd