DOCSP-33154 Make covered query info discoverable (#4762) (#4934)

* Summarized covered query benefits. Opted not to use an include

* Removed covered query info from wildcard indexes

Author: nvillahermosa-mdb

source/core/indexes/index-types/index-compound.txt

@@ -14,6 +14,11 @@ Compound Indexes
 
 .. include:: /includes/indexes/fact-compound-index-intro.rst
 
+Indexing commonly queried fields increases the
+likelihood of :ref:`covered queries <indexes-covered-queries>`. A
+covered query is a query that can be satisfied entirely using an index
+and does not have to examine any documents, leading to greatly improved performance.
+
 To create a compound index, use the following prototype:
 
 .. include:: /includes/indexes/code-examples/create-compound-index.rst
@@ -38,6 +43,11 @@ inventory items by name and quantity to determine which items are low
 stock. You can create a compound index on both the ``item`` and
 ``quantity`` fields to improve query performance.
 
+A compound index on commonly queried fields increases the chances of
+:ref:`covering <indexes-covered-queries>` those queries. Covered queries
+are queries that can be satisfied entirely using an index, without
+examining any documents. This optimizes query performance.
+
 Get Started
 -----------
 

source/core/indexes/index-types/index-compound/create-compound-index.txt

@@ -15,7 +15,10 @@ Create a Compound Index
 **Compound indexes** are indexes that contain references to multiple
 fields. Compound indexes improve performance for queries on exactly the
 fields in the index or fields in the :ref:`index prefix
-<compound-index-prefix>`.
+<compound-index-prefix>`. Indexing commonly queried fields increases the
+chances of :ref:`covering <indexes-covered-queries>` those queries,
+meaning MongoDB can satisfy the query entirely with the index,
+without examining documents.
 
 To create a compound index, use the
 :method:`db.collection.createIndex()` method:

source/core/indexes/index-types/index-geospatial.txt

@@ -51,6 +51,10 @@ on the ``location`` field. After creating the index, you can query
 using the :query:`$near` operator to return a list of nearby stations, 
 sorted from nearest to farthest.
 
+Indexing commonly queried fields increases the chances of :ref:`covering <indexes-covered-queries>` those queries. Covered queries
+are queries that can be satisfied entirely using an index, without
+examining any documents. This optimizes query performance.
+
 Get Started
 -----------
 

source/core/indexes/index-types/index-multikey.txt

@@ -48,6 +48,10 @@ Use Cases
 If your application frequently queries a field that contains an array
 value, a multikey index improves performance for those queries.
 
+Indexing commonly queried fields increases the chances of :ref:`covering <indexes-covered-queries>` those queries. Covered queries
+are queries that can be satisfied entirely using an index, without
+examining any documents. This optimizes query performance.
+
 For example, documents in a ``students`` collection contain a
 ``test_scores`` field: an array of test scores a student received
 throughout the semester. You regularly update a list of top students:

source/core/indexes/index-types/index-single.txt

@@ -66,6 +66,11 @@ human resources department often needs to look up employees by employee
 ID. You can create an index on the employee ID field to improve the
 performance of that query.
 
+Indexing commonly queried fields increases the chances of :ref:`covering
+<indexes-covered-queries>` those queries. Covered queries are queries
+that can be satisfied entirely using an index, without examining any
+documents. This optimizes query performance.
+
 Get Started
 -----------
 

source/core/indexes/index-types/index-single/create-single-field-index.txt

@@ -13,7 +13,10 @@ Create an Index on a Single Field
    :class: singlecol
 
 You can create an index on a single field to improve performance for
-queries on that field.
+queries on that field. Indexing commonly queried fields increases the
+chances of :ref:`covering <indexes-covered-queries>` those queries,
+meaning MongoDB can satisfy the query entirely with the index,
+without examining documents.
 
 To create a single-field index, use the
 :method:`db.collection.createIndex()` method:

source/core/indexes/index-types/index-text.txt

@@ -22,6 +22,10 @@ searching for specific words or phrases within string content.
 A collection can only have **one** text index, but that index can cover 
 multiple fields.
 
+Indexing commonly queried fields increases the chances of :ref:`covering <indexes-covered-queries>` those queries. Covered queries
+are queries that can be satisfied entirely using an index, without
+examining any documents. This optimizes query performance.
+
 To create a text index, use the following prototype:
 
 .. include:: /includes/indexes/code-examples/create-text-index.rst