[DOC-12715] Document New Search Request Params for Search Fine-Tuning (#291)

* [quickfix]: quickfix: strange font problem on diagram (#274)

Seems to have been caused by extra space in the label.

* [DOC-12610]: Document `nprobe` tweaking

* [DOC=12610]: Moved fine-tuning menu entry.
[DOC=12610]: Moved the stem declaration; wasn't working in the old position.

* [DOC=12610]:
Moved and reworded the sections for clarity.
Adding link to search-index-params.adoc

* [DOC-12715] Add documentation to the JSON search request example and topics around the new added memory-efficient setting and the params object for probe and centroid tuning

* [DOC-12715] Adding on to Ray's documentation to provide a link to Search Request Params.

* [DOC-12715] Comments from peer review

---------

Co-authored-by: Ray Offiah <[email protected]>
Co-authored-by: Ray Offiah <[email protected]>

Author: sarahlwelton

modules/search/examples/run-search-full-request.jsonc

@@ -47,6 +47,10 @@
     "knn": [
         {
             "k": 10,
+            "params": {
+                "ivf_nprobe_pct": 1,
+                "ivf_max_codes_pct": 0.2
+            },
             "field": "vector_field",
             "vector": [ 0.707106781186548, 0, 0.707106781186548 ]
         }

modules/search/pages/search-request-params.adoc

@@ -173,6 +173,12 @@ The Search Service returns the `k` closest vectors to the vector given in `vecto
 
 NOTE: The <<size-limit,size or limit property>> overrides any value set in `k`.
 
+|params |Object |No a|
+
+Enter additional parameters to control how the Search Service compares vectors when running a Vector Search request. 
+
+For more information about the `params` object, see <<knn-params,>>.
+
 |field |String |Yes a|
 
 The name of the field that contains the vector data you want to search. 
@@ -199,6 +205,40 @@ For more information about the dimension value, see the xref:search-index-params
 
 |====
 
+[#knn-params]
+=== Knn params Object 
+
+Use the `params` object inside a `knn` object to fine tune the probes and centroids the Search Services uses and searches while running a Vector Search request. 
+
+The `params` object can contain the following properties: 
+
+[cols="1,1,1,4"]
+|====
+|Property |Type |Required? |Description
+
+|ivf_nprobe_pct |Number (percentage) |No a|
+
+Set the `ivf_nprobe_pct` value to control the percentage of probes, or the percentage of clusters, that the Search Service searches during a single Vector Search query.
+
+The Search Service automatically calculates a default `nprobe` percentage based on the vectors in a given partition of your Vector Search index.
+For more information about this calculation, see xref:vector-search:fine-tune-vector-search.adoc[].
+
+If you set the value of `ivf_nprobe_pct` higher than this default calculated value, the Search Service will search a higher percentage of clusters in your processed vectors.
+This can increase your accuracy and recall for Vector Search, but requires more compute time for each query. 
+
+In the example, the Search Service searches only `1%` of the total available clusters. 
+
+|ivf_max_codes_pct |Number (percentage out of 100) |No a|
+
+Set the `ivf_max_codes_pct` value to control the maximum number of centroids that the Search Service accesses during a single Vector Search query. 
+
+By default, this value is always 100%. 
+
+If you reduce your `ivf_max_codes_pct` value, the Search Service accesses fewer centroids, which reduces your Vector Search accuracy and recall, but gives faster compute times for your search. 
+
+In the example, the Search Service searches only `0.2%` of the available centroids in your vector data. 
+|====
+
 [#query-object]
 == Query Object 
 

modules/search/partials/vector-search-field-descriptions.adoc

@@ -1,5 +1,5 @@
 // tag::optimized_for[]
-For a `vector` child field, choose whether the Search Service should prioritize recall or latency when returning similar vectors in search results:
+For a `vector` child field, choose whether the Search Service should prioritize recall, latency, or memory efficiency when returning similar vectors in search results:
 
 * *recall*: The Search Service prioritizes returning the most accurate result.
 This may increase resource usage for Search queries.
@@ -12,6 +12,11 @@ This may reduce the accuracy of results.
 +
 The Search Service uses half the `nprobe` value calculated for *recall* priority. 
 
+* *memory-efficient*: The Search Service prioritizes reducing memory usage and optimizes search operations for less resources.
+This may reduce both accuracy (recall) and latency.
++
+The Search Service uses either an inverted file index with scalar quantization, or a directly mapped index with exact vector comparisons, depending on the number of vectors in your data.
+
 For more information about Vector Search indexes, see xref:vector-search:vector-search.adoc[] or xref:vector-search:create-vector-search-index-ui.adoc[].
 // end::optimized_for[]
 // tag::similarity_metric[]

modules/vector-search/pages/fine-tune-vector-search.adoc

@@ -119,7 +119,7 @@ If you have a Vector Search index with `vector_index_optimized_for` set to `"rec
 == Fine-Tuning Query Parameters
 
 
-You can add set the values of `ivf_nprobe_pct` and `ivf_max_codes_pct` in your Vector Search queries to tune the recall or accuracy of your search.
+You can set the values of `ivf_nprobe_pct` and `ivf_max_codes_pct` in your Vector Search queries to tune the recall or accuracy of your search.
 
 You can add the following parameters to your query: