IBX-8713: Messenger support in CDP described

docs/cdp/cdp_activation/cdp_data_export.md

@@ -134,6 +134,42 @@ Finally, you can specify the audiences you wish to include.
 
     All CDP requests are logged in with `debug` severity.
 
+### [[= product_name_base =]] Messenger support for large batches of data
+
+CDP uses [[= product_name_base =]] Messenger to process incoming data from [Raptor](https://www.raptorservices.com/).
+This approach improves performance and reliability when processing large amounts of CDP user records.
+For more information, see [Background tasks: How it works](background_tasks.md#how-it-works).
+
+By using Messenger while working with large batches of data, requests are queued instead of being processed synchronously:
+
+- queuing items starts automatically once a certain number of actions is reached (below this number, items are processed in a single request, using the standard synchronous behavior)
+- every single data is recorded in the database
+- a background worker retrieves records from the queue, processing them one by one or in batches, depending on the [Messenger]([[= symfony_doc =]]/messenger.html) configuration
+- processing happens at set intervals to avoid timeouts and keep the system stable
+
+1\. Make sure that the transport layer is [defined properly](background_tasks.md#configure-package) in [[= product_name_base =]] Messenger configuration.
+
+2\. Add `bulk_async_threshold` setting in the `config/packages/ibexa_cdp.yaml` configuration:
+
+``` bash
+ibexa_cdp:
+      bulk_async_threshold: 100  # Default: 100 items
+```
+
+Available options:
+
+- `bulk_async_threshold` (integer, default: 100) - minimum number of items required to trigger asynchronous processing
+    - below threshold - items are processed immediately in a single request, using the standard synchronous behavior
+    - at/above threshold - items are automatically dispatched to the asynchronous queue for background processing
+
+3\. Make sure that the [worker starts](background_tasks.md#start-worker) together with the application to watch the transport bus:
+
+``` bash
+php bin/console messenger:consume ibexa.messenger.transport --bus=ibexa.messenger.bus
+```
+
+For more information, see [Start background task worker](background_tasks.md#start-worker).
+
 ### CDP Monolog channel
 
 CDP Monolog channel handles webhook logs for easier separation of logs.
@@ -150,7 +186,7 @@ It can be configured in both `dev` and `prod` environments, for example:
 
 ```yaml
 monolog:
-     handlers:
+    handlers:
         cdp_webhook:
             type: stream
             path: "%kernel.logs_dir%/cdp_webhook_%kernel.environment%.log"

docs/cdp/cdp_data_export_schedule.md

@@ -65,4 +65,4 @@ php bin/console ibexa:cdp:stream-product-data --help
 
 ```bash
 php bin/console ibexa:cdp:stream-content-data --help
-```
+```

docs/update_and_migration/from_4.6/update_from_4.6.md

@@ -566,6 +566,11 @@
 composer require guzzlehttp/guzzle:^6.5 php-http/guzzle6-adapter:^2.0
 ```
 
+### Messenger support in CDP
+
+If you're using [CDP](cdp.md) and haven't configured Ibexa Messenger yet, do so now.
+Follow the [Messenger setup instructions](https://doc.ibexa.co/en/4.6/infrastructure_and_maintenance/background_tasks/#install-package) to continue.
+
 <!-- End of update instructions -->
 
 [[% include 'snippets/update/notify_support.md' %]]