Update README.md

README.md

@@ -29,6 +29,16 @@ It's simple. It doesn't do anything supernatural, it doesn't have Rocket Science
 This is a simple ant with some mathematical abilities that takes data from one place, sorts/transforms/adapts/calculate them and puts them in another place.  
 Sometimes he has to go to a lot of endpoints to collect what needs to be taken to the storage (that's the way Yandex.Tracker API).
 
+**Important.**
+
+By default, the exporter processes only those tasks that were changed during the sliding window specified in the `EXPORTER_TRACKER__SEARCH__RANGE` parameter.  
+So, all tasks that have activity (changes) will be uploaded to the storage. Something like eventual consistency.
+
+If you need to upload historical data that will never be updated again, you can flexibly control behavior through the [environment variables described below](#general-settings).  
+Here are some recipes for a one-shot export:
+1. Launch a exporter with the parameter `EXPORTER_TRACKER__SEARCH__RANGE`, for example, a year ago
+2. More specifically: describe the query in the tracker's QL format using the `EXPORTER_TRACKER__SEARCH__QUERY` environment variable. This way you can export point bundles of tasks and bypass with the [Tracker's strict limit of 10,000 tasks](https://github.com/yandex/yandex_tracker_client/issues/13).
+
 
 **Collects:**
 - Issue metadata (i.e. title, author, assignee, components, tags, status, etc)