Merge pull request #189079 from Venkat1340/Users/Venkat1340/Performancetips

MsDocs: Performance and Metadata requests (V2 SDK)

Author: PRMerger-2

articles/cosmos-db/sql/performance-tips.md

@@ -6,7 +6,7 @@ author: StefArroyo
 ms.service: cosmos-db
 ms.subservice: cosmosdb-sql
 ms.topic: how-to
-ms.date: 01/24/2022
+ms.date: 02/18/2022
 ms.devlang: csharp
 ms.custom: devx-track-dotnet, contperf-fy21q2
 
@@ -64,6 +64,10 @@ If you're testing at high throughput levels (more than 50,000 RU/s), the client
 > [!NOTE] 
 > High CPU usage can cause increased latency and request timeout exceptions.
 
+## <a id="metadata-operations"></a> Metadata operations
+
+Do not verify a Database and/or Collection exists by calling `Create...IfNotExistsAsync` and/or `Read...Async` in the hot path and/or before doing an item operation. The validation should only be done on application startup when it is necessary, if you expect them to be deleted (otherwise it's not needed). These metadata operations will generate extra end-to-end latency, have no SLA, and their own separate [limitations](https://aka.ms/CosmosDB/sql/errors/metadata-429) that do not scale like data operations.
+
 ## <a id="logging-and-tracing"></a> Logging and tracing
 
 Some environments have the [.NET DefaultTraceListener](/dotnet/api/system.diagnostics.defaulttracelistener) enabled. The DefaultTraceListener poses performance issues on production environments causing high CPU and I/O bottlenecks. Check and make sure that the DefaultTraceListener is disabled for your application by removing it from the [TraceListeners](/dotnet/framework/debug-trace-profile/how-to-create-and-initialize-trace-listeners) on production environments.