DOCS-16389 query plan cache subdocument (#5217)

* DOCS-16389 query plan cache subdocument

* *

* IF feedback

* clarity

* nit

* move to compatibility

* *

* wording

* wording

Author: ajhuh-mdb

source/reference/command/serverStatus.txt

@@ -1645,7 +1645,6 @@ metrics
       },
       query: {
          allowDiskUseFalse: Long("<num>"),
-         planCacheTotalSizeEstimateBytes: Long("<num>"),
          updateOneOpStyleBroadcastWithExactIDCount: Long("<num>"),
          lookup: {
             hashLookup: Long("<num>"),
@@ -3854,15 +3853,42 @@ planCache
 
 .. code-block:: javascript
 
-   planCache: {
-      classic: { hits: Long("<num>"), misses: Long("<num>") },
-      sbe: { hits: Long("<num>"), misses: Long("<num>") }
+   planCache : {
+      totalQueryShapes : Long("<num>"),
+      totalSizeEstimateBytes : Long("<num>"),
+      classic : { 
+         hits : Long("<num>"), 
+         misses : Long("<num>") 
+      },
+      sbe : { 
+         hits : Long("<num>"), 
+         misses: Long("<num>") 
+      }
    }
 
 .. serverstatus:: planCache
 
    A document that reports query plan cache statistics.
 
+.. serverstatus:: planCache.totalQueryShapes
+      
+   Approximate number of :term:`query shapes <query shape>`. 
+
+   Prior to version 7.2, information on the number of query shapes was stored in 
+   the ``query.planCacheTotalQueryShapes`` field.
+
+   .. versionadded:: 7.2
+
+.. serverstatus:: planCache.totalSizeEstimateBytes
+
+   Total size of the plan cache in bytes.
+
+   Prior to version 7.2, information on the plan cache size was stored in the  
+   ``query.planCacheTotalSizeEstimateBytes`` field.
+
+
+   .. versionadded:: 7.2
+
 .. serverstatus:: planCache.classic.hits
 
    Number of classic execution engine query plans found in the query 
@@ -3875,12 +3901,12 @@ planCache
 
 .. serverstatus:: planCache.sbe.hits
 
-   Number of slot-based execution engine query plans found in the query 
+   Number of |sbe-short| query plans found in the query 
    cache and reused to avoid the query planning phase.
 
 .. serverstatus:: planCache.sbe.misses
 
-   Number of slot-based execution engine query plans which were not found 
+   Number of |sbe-short| plans which were not found 
    in the query cache and went through the query planning phase.
 
 .. _server-status-queryAnalyzers:                                       
@@ -6741,7 +6767,7 @@ wiredTiger
 
    .. serverstatus:: wiredTiger.cache.bytes currently in the cache
 
-      Size in byte of the data currently in cache. This value should
+      Size in bytes of the data currently in cache. This value should
       not be greater than the ``maximum bytes configured`` value.
 
    .. serverstatus:: wiredTiger.cache.unmodified pages evicted

source/release-notes/7.2-compatibility.txt

@@ -23,3 +23,16 @@ Backward-Incompatible Features
 
 General Changes
 ---------------
+
+``serverStatus`` Metrics
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Starting in MongoDB 7.2, the :dbcommand:`serverStatus` command and the
+:method:`db.serverStatus()` method have these output changes:
+
+Renamed Metrics
+```````````````
+
+- ``query.planCacheTotalQueryShapes`` is now :serverstatus:`planCache.totalQueryShapes`
+- ``query.planCacheTotalSizeEstimateBytes`` is now :serverstatus:`planCache.totalSizeEstimateBytes`
+