[ES\QL] Add a section for vector functions in the doc.

docs/reference/query-languages/esql/_snippets/lists/vector-functions.md

@@ -0,0 +1,7 @@
+* [`KNN`](../../functions-operators/vector-functions.md#esql-knn)
+% * {applies_to}`stack: development` {applies_to}`serverless: preview` [`V_COSINE`](../../functions-operators/vector-functions.md#esql-v_cosine)
+% * {applies_to}`stack: development` {applies_to}`serverless: preview` [`V_DOT_PRODUCT`](../../functions-operators/vector-functions.md#esql-v_dot_product)
+% * {applies_to}`stack: preview` {applies_to}`serverless: preview` [`V_HAMMING`](../../functions-operators/vector-functions.md#esql-v_hamming)
+% * {applies_to}`stack: development` {applies_to}`serverless: preview` [`V_L1_NORM`](../../functions-operators/vector-functions.md#esql-v_l1_norm)
+% * {applies_to}`stack: development` {applies_to}`serverless: preview` [`V_L2_NORM`](../../functions-operators/vector-functions.md#esql-v_l2_norm)
+% * {applies_to}`stack: development` {applies_to}`serverless: preview` [`V_MAGNITUDE`](../../functions-operators/vector-functions.md#esql-v_magnitude)

docs/reference/query-languages/esql/esql-functions-operators.md

@@ -80,6 +80,12 @@ mapped_pages:
 :::
 ::::
 
+::::{dropdown} Vector functions
+:open:
+:::{include} _snippets/lists/vector-functions.md
+:::
+::::
+
 ::::{dropdown} Multi value functions
 :open:
 :::{include} _snippets/lists/mv-functions.md

docs/reference/query-languages/esql/functions-operators/search-functions.md

@@ -43,6 +43,9 @@ for information on the limitations of full text search.
 :::{include} ../_snippets/functions/layout/kql.md
 :::
 
+:::{include} ../_snippets/functions/layout/knn.md
+:::
+
 :::{include} ../_snippets/functions/layout/match.md
 :::
 

docs/reference/query-languages/esql/functions-operators/vector-functions.md

@@ -0,0 +1,61 @@
+---
+applies_to:
+  stack: preview
+  serverless: preview
+navigation_title: "Vector functions"
+mapped_pages:
+  - https://www.elastic.co/guide/en/elasticsearch/reference/current/esql-functions-operators.html#esql-vector-functions
+---
+
+# {{esql}} vector functions [esql-vector-functions]
+
+{{esql}} supports vector functions for dense vector similarity calculations and k-nearest neighbor search.
+
+:::{note}
+Vector functions are currently in **preview** and may change in future versions.
+They work with `dense_vector` fields and require appropriate field mappings.
+:::
+
+{{esql}} supports these vector functions:
+
+:::{include} ../_snippets/lists/vector-functions.md
+:::
+
+:::{include} ../_snippets/functions/layout/knn.md
+:::
+
+% V_COSINE is currently a hidden feature
+% To make it visible again, uncomment this and the line in
+% lists/vector-functions.md
+% :::{include} ../_snippets/functions/layout/v_cosine.md
+% :::
+
+% V_DOT_PRODUCT is currently a hidden feature
+% To make it visible again, uncomment this and the line in
+% lists/vector-functions.md
+% :::{include} ../_snippets/functions/layout/v_dot_product.md
+% :::
+
+% V_HAMMING is currently a hidden feature
+% To make it visible again, uncomment this and the line in
+% lists/vector-functions.md
+% :::{include} ../_snippets/functions/layout/v_hamming.md
+% :::
+
+% V_L1_NORM is currently a hidden feature
+% To make it visible again, uncomment this and the line in
+% lists/vector-functions.md
+% :::{include} ../_snippets/functions/layout/v_l1_norm.md
+% :::
+
+% V_L2_NORM is currently a hidden feature
+% To make it visible again, uncomment this and the line in
+% lists/vector-functions.md
+% :::{include} ../_snippets/functions/layout/v_l2_norm.md
+% :::
+
+% V_MAGNITUDE is currently a hidden feature
+% To make it visible again, uncomment this and the line in
+% lists/vector-functions.md
+% :::{include} ../_snippets/functions/layout/v_magnitude.md
+% :::

docs/reference/query-languages/toc.yml

@@ -133,6 +133,7 @@ toc:
               - file: esql/functions-operators/search-functions.md
               - file: esql/functions-operators/spatial-functions.md
               - file: esql/functions-operators/string-functions.md
+              - file: esql/functions-operators/vector-functions.md
               - file: esql/functions-operators/type-conversion-functions.md
               - file: esql/functions-operators/mv-functions.md
               - file: esql/functions-operators/operators.md

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/vector/Knn.java

@@ -153,7 +153,7 @@ public Knn(
                         + "(docs-content://solutions/search/vector/knn.md#dense-vector-knn-search-rescoring) for details."
                 ), },
             description = "(Optional) kNN additional options as <<esql-function-named-params,function named parameters>>."
-                + " See <<query-dsl-knn-query,knn query>> for more information.",
+                + " See [knn query](/reference/query-languages/query-dsl/query-dsl-knn-query.md) for more information.",
             optional = true
         ) Expression options
     ) {