update documentation

docs/configuration/node-config.md

@@ -191,7 +191,7 @@ This section contains the configuration options for a Searcher.
 
 | Property | Description | Default value |
 | --- | --- | --- |
-| `aggregation_memory_limit` | Controls the maximum amount of memory that can be used for aggregations before aborting. This limit is per request and single leaf query (a leaf query is querying one or multiple splits concurrently). It is used to prevent excessive memory usage during the aggregation phase, which can lead to performance degradation or crashes. Since it is per request, concurrent requests can exceed the limit. | `500M`|
+| `aggregation_memory_limit` | Controls the maximum amount of memory that can be used for aggregations before aborting. This limit is per searcher node. A node may run concurrent queries, which share the limit. The first query that will hit the limit will be aborted and frees its memory. It is used to prevent excessive memory usage during the aggregation phase, which can lead to performance degradation or crashes. | `500M`|
 | `aggregation_bucket_limit` | Determines the maximum number of buckets returned to the client. | `65000` |
 | `fast_field_cache_capacity` | Fast field in memory cache capacity on a Searcher. If your filter by dates, run aggregations, range queries, or if you use the search stream API, or even for tracing, it might worth increasing this parameter. The [metrics](../reference/metrics.md) starting by `quickwit_cache_fastfields_cache` can help you make an informed choice when setting this value. | `1G` |
 | `split_footer_cache_capacity` | Split footer in memory cache (it is essentially the hotcache) capacity on a Searcher.| `500M` |