Add random sort aggregation plugin

_aggregations/bucket/index.md

@@ -39,8 +39,9 @@ OpenSearch supports the following bucket aggregations:
 - [Multi-terms]({{site.url}}{{site.baseurl}}/aggregations/bucket/multi-terms/)
 - [Nested]({{site.url}}{{site.baseurl}}/aggregations/bucket/nested/)
 - [Range]({{site.url}}{{site.baseurl}}/aggregations/bucket/range/)
+- [Random sort]({{site.url}}{{site.baseurl}}/aggregations/bucket/random-sort/)
 - [Reverse nested]({{site.url}}{{site.baseurl}}/aggregations/bucket/reverse-nested/)
 - [Sampler]({{site.url}}{{site.baseurl}}/aggregations/bucket/sampler/)
 - [Significant terms]({{site.url}}{{site.baseurl}}/aggregations/bucket/significant-terms/)
 - [Significant text]({{site.url}}{{site.baseurl}}/aggregations/bucket/significant-text/)
-- [Terms]({{site.url}}{{site.baseurl}}/aggregations/bucket/terms/)
+- [Terms]({{site.url}}{{site.baseurl}}/aggregations/bucket/terms/)

_aggregations/bucket/random-sort.md

@@ -0,0 +1,100 @@
+---
+layout: default
+title: Random sort
+parent: Bucket aggregations
+nav_order: 165
+---
+
+# Random sort
+
+The random sort plugin allows you to sort search results randomly. This can be useful for implementing features like randomized search results or A/B testing.
+
+## Installation
+
+The random sort plugin is not installed by default. To install it, use the plugin install command:
+
+```bash
+bin/opensearch-plugin install random-sort
+```
+
+## Usage
+
+To use random sorting, add a `sort` parameter to your search request with the following syntax:
+
+```json
+{
+  "sort": [
+    {
+      "_script": {
+        "type": "number",
+        "script": {
+          "lang": "randomsort",
+          "source": "random_sort"
+        },
+        "order": "asc"
+      }
+    }
+  ]
+}
+```
+
+You can optionally provide a `seed` parameter to ensure consistent randomization across requests:
+
+```json
+{
+  "sort": [
+    {
+      "_script": {
+        "type": "number",
+        "script": {
+          "lang": "randomsort",
+          "source": "random_sort",
+          "params": {
+            "seed": 1234
+          }
+        },
+        "order": "asc"
+      }
+    }
+  ]
+}
+```
+
+## Example
+
+Here's a complete example of a search request using random sort:
+
+```json
+GET /my-index/_search
+{
+  "size": 10,
+  "query": {
+    "match_all": {}
+  },
+  "sort": [
+    {
+      "_script": {
+        "type": "number",
+        "script": {
+          "lang": "randomsort",
+          "source": "random_sort",
+          "params": {
+            "seed": 1234
+          }
+        },
+        "order": "asc"
+      }
+    }
+  ]
+}
+```
+
+This will return 10 documents from `my-index`, sorted in a random order. The randomization will be consistent across requests as long as the same seed is used.
+
+## How it works
+
+The random sort plugin implements a custom script engine that generates a random number for each document. This number is then used as the sort key. When a seed is provided, it ensures that the same sequence of random numbers is generated for each document across multiple requests.
+
+## Performance considerations 
+
+While random sorting can be useful, it may impact query performance, especially on large datasets. The plugin has to generate a random number for each matching document, which can be computationally expensive. Use this feature judiciously and consider its impact on your overall system performance.

_plugins/search-history.md

@@ -0,0 +1,68 @@
+---
+layout: default
+title: Search history
+nav_order: 140
+has_children: false
+parent: Plugins
+---
+
+# Search history plugin
+
+The search history plugin allows you to save and retrieve a user's search history in OpenSearch. This can be useful for enabling features like recent searches or personalized search suggestions.
+
+## Installation 
+
+The search history plugin is included with OpenSearch by default. No additional installation steps are required.
+
+## Configuration
+
+The plugin has two main configuration settings that can be adjusted in `opensearch.yml`:
+
+```yaml
+search.history.max_size: 100  # Maximum number of searches to store per user
+search.history.retention_days: 30  # Number of days to retain search history
+```
+
+## Usage
+
+The plugin provides REST APIs for saving and retrieving search history:
+
+### Save search history
+
+```
+POST /_search_history
+{
+  "query": "my search query",
+  "indices": ["index1", "index2"],
+  "hit_count": 53
+}
+```
+
+This saves the search query, indices searched, and number of hits to the user's search history.
+
+### Retrieve search history  
+
+```
+GET /_search_history?from=0&size=20
+```
+
+This retrieves the user's search history, paginated by the `from` and `size` parameters.
+
+### Delete search history
+
+```
+DELETE /_search_history?query=my+search+query
+```
+
+This deletes matching entries from the user's search history.
+
+## Security
+
+The plugin uses the authenticated user's ID to segregate and secure search history data. Users can only access their own search history.
+
+## Limitations
+
+- The plugin currently stores search history data in-memory and is not designed for production use with large volumes of users/searches.
+- Search history is not persisted across cluster restarts.
+
+For more details on the plugin implementation, see the [SearchHistoryPlugin](https://github.com/opensearch-project/OpenSearch/blob/main/plugins/search-history/src/main/java/org/opensearch/plugin/searchhistory/SearchHistoryPlugin.java) and [SearchHistoryService](https://github.com/opensearch-project/OpenSearch/blob/main/plugins/search-history/src/main/java/org/opensearch/plugin/searchhistory/SearchHistoryService.java) classes.