Update the docs

docs/internals/ingest-v2.md

@@ -18,7 +18,3 @@ indexer:
 See [full configuration example](https://github.com/quickwit-oss/quickwit/blob/main/config/quickwit.yaml).
 
 The only way to use the ingest API V2 is to use the [bulk endpoint](../reference/es_compatible_api.md#_bulk--batch-ingestion-endpoint) of the Elasticsearch-compatible API. The native Quickwit API is not yet compatible with the ingest V2 API.
-
-## Caveats
-
-The `refresh` parameter is not yet supported on the ingest V2 API.

docs/overview/concepts/querying.md

@@ -105,3 +105,7 @@ Quickwit does caching in many places to deliver a highly performing query engine
 ### Scoring
 
 Quickwit supports sorting docs by their BM25 scores. In order to query by score, [fieldnorms](../../configuration/index-config.md#text-type) must be enabled for the field. By default, BM25 scoring is disabled to improve query latencies but it can be opt-in by setting the `sort_by` option to `_score` in queries.
+
+### Document ID
+
+Each document in Quickwit is assigned a unique document ID which is a combination of the split ID and the Tantivy DocId within the split. You cannot assign a custom ID. This ID is used for every search query as sort order (after the explicitly specified sort values) to make the results deterministic.

docs/reference/rest-api.md

@@ -67,7 +67,7 @@ POST api/v1/<index id>/search
 | `max_hits`        | `Integer`  | Maximum number of hits to return (by default 20) | `20` |
 | `search_field`    | `[String]` | Fields to search on if no field name is specified in the query. Comma-separated list, e.g. "field1,field2"  | index_config.search_settings.default_search_fields |
 | `snippet_fields`  | `[String]` | Fields to extract snippet on. Comma-separated list, e.g. "field1,field2"  | |
-| `sort_by`         | `[String]` | Fields to sort the query results on. You can sort by one or two fast fields or by BM25 `_score` (requires fieldnorms). By default, hits are sorted by their document ID. | |
+| `sort_by`         | `[String]` | Fields to sort the query results on. You can sort by one or two fast fields or by BM25 `_score` (requires fieldnorms). By default, hits are sorted in reverse order of their [document ID](/docs/overview/concepts/querying.md#document-id) (to show recent events first). | |
 | `format`          | `Enum`     | The output format. Allowed values are "json" or "pretty_json" | `pretty_json` |
 | `aggs`            | `JSON`     | The aggregations request. See the [aggregations doc](aggregation.md) for supported aggregations. | |