added recommendation

Signed-off-by: Amit Mor <[email protected]>
Signed-off-by: Amit Mor <[email protected]>

daprdocs/content/en/reference/components-reference/supported-pubsub/setup-aws-snssqs.md

@@ -9,15 +9,16 @@ aliases:
 
 ## Component format
 
-To set up AWS SNS/SQS pub/sub, create a component of type `pubsub.aws.snssqs`. 
+To set up AWS SNS/SQS pub/sub, create a component of type `pubsub.aws.snssqs`.
 
 By default, the AWS SNS/SQS component:
+
 - Generates the SNS topics
 - Provisions the SQS queues
 - Configures a subscription of the queues to the topics
 
 {{% alert title="Note" color="primary" %}}
-If you only have a publisher and no subscriber, only the SNS topics are created. 
+If you only have a publisher and no subscriber, only the SNS topics are created.
 
 However, if you have a subscriber, SNS, SQS, and the dynamic or static subscription thereof are generated.
 {{% /alert %}}
@@ -136,6 +137,11 @@ When running the Dapr sidecar (`daprd`) with your application on EKS (AWS Kubern
 #### SNS/SQS Contention with Dapr
 
 Fundamentally, SNS aggregates messages from multiple publisher topics into a single SQS queue by creating SQS subscriptions to those topics. As a subscriber, the SNS/SQS PubSub component consumes messages from that sole SQS queue. However, like any SQS consumer, the component cannot selectively retrieve only messages published to specific SNS topics it is configured to subscribe to. This can result in the component receiving messages originating from topics without associated handlers. Typically this occurs during component initialization, if infrastructure subscriptions are ready before component subscription handlers, or during shutdown, if component handlers are removed before infrastructure subscriptions. Since this issue affects any SQS consumer of multiple SNS topics, the component cannot prevent consuming messages from topics lacking handlers. When this happens, the component logs an error indicating such messages were erroneously retrieved.
+In these situations, the unhandled messages would reappear in SQS with their [receive count](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-dead-letter-queues.html#sqs-receive-count) decremented after each pull. Thus, there is a risk that an unhandled message could exceed its `messageReceiveLimit` and be lost.
+
+{{% alert title="Important" color="warning" %}}
+It is therefore advisable to consider potential contention scenarios when using SNS/SQS with Dapr, and configure `messageReceiveLimit` appropriately. It is also highly recommended to use SQS dead-letter queues by setting `sqsDeadLettersQueueName` to prevent losing messages.
+{{% /alert %}}
 
 ## Create an SNS/SQS instance