updated

Author: spelluru

articles/event-grid/event-schema-resource-groups.md

@@ -24,6 +24,9 @@ To programmatically handle events, you can sort events by looking at the `operat
 
 The event subject is the resource ID of the resource that is the target of the operation. To filter events for a resource, provide that resource ID when creating the event subscription.  To filter by a resource type, use a value in following format: `/subscriptions/<subscription-id>/resourcegroups/<resource-group>/providers/Microsoft.Compute/virtualMachines`
 
+> [!NOTE]
+> Resource creation doesn't always map to a single write operation. For a lot of resources, this isn't true since resource creation is a 2 step process. An initial write when the resource creation request is accepted followed by a write when the resource is actually created (or can involve more write for cases where VMs with extension are provisioned). You should explicitly query Azure Resource Manager when processing a write event to get correct state of the resource.
+
 
 ## Event Grid event schema
 

articles/event-grid/event-schema-subscriptions.md

@@ -24,6 +24,8 @@ To programmatically handle events, you can sort events by looking at the `operat
 
 The event subject is the resource ID of the resource that is the target of the operation. To filter events for a resource, provide that resource ID when creating the event subscription. To filter by a resource type, use a value in following format: `/subscriptions/<subscription-id>/resourcegroups/<resource-group>/providers/Microsoft.Compute/virtualMachines`
 
+> [!NOTE]
+> Resource creation doesn't always map to a single write operation. For a lot of resources, this isn't true since resource creation is a 2 step process. An initial write when the resource creation request is accepted followed by a write when the resource is actually created (or can involve more write for cases where VMs with extension are provisioned). You should explicitly query Azure Resource Manager when processing a write event to get correct state of the resource.
 
 ## Event Grid event schema
 

articles/event-grid/handler-event-hubs.md

@@ -22,5 +22,16 @@ Use **Event Hubs** when your solution gets events faster than it can process the
 | [Quickstart: route custom events to Azure Event Hubs with Azure CLI and Event Grid](custom-event-to-eventhub.md) | Sends a custom event to an event hub for processing by an application. |
 | [Resource Manager template: custom topic and Event Hubs endpoint](https://github.com/Azure/azure-quickstart-templates/tree/master/101-event-grid-event-hubs-handler)| A Resource Manager template that creates a subscription for a custom topic. It sends events to an Azure Event Hubs. |
 
+## Message headers
+Set the following message headers when sending events as messages to a Service Bus endpoint.
+
+| Property name | Description |
+| ------------- | ----------- | 
+| aeg-subscription-name | Name of event subscription. |
+| aeg-delivery-count | Number of attempts made for the event. Example: "1" |
+| aeg-data-version | Data version of the event. Example: "1" |
+| aeg-metadata-version | Metadata version of the event. Example: "1" |
+| aeg-event-type | Event type. Example: "Microsoft.Storage.blobCreated" | 
+
 ## Next steps
 For an introduction to Event Grid, see [About Event Grid](overview.md).

articles/event-grid/handler-service-bus.md

@@ -13,6 +13,7 @@ ms.author: spelluru
 # Service Bus queues and topics as event handlers for Azure Event Grid events
 An event handler is the place where the event is sent. The handler takes some further action to process the event. Several Azure services are automatically configured to handle events and **Azure Service Bus** is one of them. 
 
+
 ## Service Bus queues
 You can route events in Event Grid directly to Service Bus queues for use in buffering or command & control scenarios in enterprise applications.
 
@@ -56,6 +57,21 @@ az eventgrid event-subscription create \
     --endpoint /subscriptions/{SubID}/resourceGroups/TestRG/providers/Microsoft.ServiceBus/namespaces/ns1/topics/topic1
 ```
 
+## Message headers
+Set the following message headers when sending events as messages to a Service Bus endpoint.
+
+| Property name | Description |
+| ------------- | ----------- | 
+| aeg-subscription-name | Name of event subscription. |
+| aeg-delivery-count | Number of attempts made for the event. Example: "1" |
+| aeg-data-version | Data version of the event. Example: "1" |
+| aeg-metadata-version | Metadata version of the event. Example: "1" |
+| aeg-event-type | Event type. Example: "Microsoft.Storage.blobCreated" | 
+
+
+## Duplicate detection
+When sending events to a Service Bus endpoint as brokered messages, the `messageid` of the brokered message is the event ID. This will be maintained across redelivery of the event so that you can avoid duplicate deliveries by turning on **duplicate detection** on service bus entity. We recommend that you enable duration of the duplicate detection on the Service Bus entity to be either the time-to-live (TTL) of the event or max retry duration, which ever is longer.
+
 ## Next steps
 
 * For an introduction to Event Grid, see [About Event Grid](overview.md).