DOCS-7942 Added statement that dataSize is uncompressed and outlined …

source/includes/ref-toc-command-diagnostic.yaml

@@ -1,24 +1,3 @@
-name: ":dbcommand:`explain`"
-file: /reference/command/explain
-description: |
-   Returns information on the execution of various operations.
----
-name: ":dbcommand:`listDatabases`"
-file: /reference/command/listDatabases
-description: "Returns a document that lists all databases and returns basic database statistics."
----
-name: ":dbcommand:`dbHash`"
-file: /reference/command/dbHash
-description: "Returns hash value a database and its collections."
----
-name: ":dbcommand:`driverOIDTest`"
-file: /reference/command/driverOIDTest
-description: "Internal command that converts an ObjectId to a string to support tests."
----
-name: ":dbcommand:`listCommands`"
-file: /reference/command/listCommands
-description: "Lists all database commands provided by the current :program:`mongod` instance."
----
 name: ":dbcommand:`availableQueryOptions`"
 file: /reference/command/availableQueryOptions
 description: "Internal command that reports on the capabilities of the current MongoDB instance."
@@ -35,16 +14,6 @@ name: ":dbcommand:`connPoolStats`"
 file: /reference/command/connPoolStats
 description: "Reports statistics on the outgoing connections from this MongoDB instance to other MongoDB instances in the deployment."
 ---
-name: ":dbcommand:`shardConnPoolStats`"
-file: /reference/command/shardConnPoolStats
-description: |
-  Reports statistics on a :program:`mongos`'s connection pool for client
-  operations against shards.
----
-name: ":dbcommand:`dbStats`"
-file: /reference/command/dbStats
-description: "Reports storage utilization statistics for the specified database."
----
 name: ":dbcommand:`cursorInfo`"
 file: /reference/command/cursorInfo
 description: "Removed in MongoDB 3.2. Replaced with :serverstatus:`metrics.cursor`."
@@ -53,14 +22,55 @@ name: ":dbcommand:`dataSize`"
 file: /reference/command/dataSize
 description: "Returns the data size for a range of data. For internal use."
 ---
+name: ":dbcommand:`dbHash`"
+file: /reference/command/dbHash
+description: "Returns hash value a database and its collections."
+---
+name: ":dbcommand:`dbStats`"
+file: /reference/command/dbStats
+description: "Reports storage utilization statistics for the specified database."
+---
 name: ":dbcommand:`diagLogging`"
 file: /reference/command/diagLogging
 description: "Provides a diagnostic logging. For internal use."
 ---
+name: ":dbcommand:`driverOIDTest`"
+file: /reference/command/driverOIDTest
+description: "Internal command that converts an ObjectId to a string to support tests."
+---
+name: ":dbcommand:`explain`"
+file: /reference/command/explain
+description: |
+   Returns information on the execution of various operations.
+---
+name: ":dbcommand:`features`"
+file: /reference/command/features
+description: "Reports on features available in the current MongoDB instance."
+---
 name: ":dbcommand:`getCmdLineOpts`"
 file: /reference/command/getCmdLineOpts
 description: "Returns a document with the run-time arguments to the MongoDB instance and their parsed options."
 ---
+name: ":dbcommand:`getLog`"
+file: /reference/command/getLog
+description: "Returns recent log messages."
+---
+name: ":dbcommand:`hostInfo`"
+file: /reference/command/hostInfo
+description: "Returns data that reflects the underlying host system."
+---
+name: ":dbcommand:`isSelf`"
+file: /reference/command/isSelf
+description: "Internal command to support testing."
+---
+name: ":dbcommand:`listCommands`"
+file: /reference/command/listCommands
+description: "Lists all database commands provided by the current :program:`mongod` instance."
+---
+name: ":dbcommand:`listDatabases`"
+file: /reference/command/listDatabases
+description: "Returns a document that lists all databases and returns basic database statistics."
+---
 name: ":dbcommand:`netstat`"
 file: /reference/command/netstat
 description: "Internal command that reports on intra-deployment connectivity. Only available for :program:`mongos` instances."
@@ -73,35 +83,25 @@ name: ":dbcommand:`profile`"
 file: /reference/command/profile
 description: "Interface for the :ref:`database profiler <profiler>`."
 ---
-name: ":dbcommand:`validate`"
-file: /reference/command/validate
-description: "Internal command that scans for a collection's data and indexes for correctness."
+name: ":dbcommand:`serverStatus`"
+file: /reference/command/serverStatus
+description: "Returns a collection metrics on instance-wide resource utilization and status."
+---
+name: ":dbcommand:`shardConnPoolStats`"
+file: /reference/command/shardConnPoolStats
+description: |
+  Reports statistics on a :program:`mongos`'s connection pool for client
+  operations against shards.
 ---
 name: ":dbcommand:`top`"
 file: /reference/command/top
 description: "Returns raw usage statistics for each database in the :program:`mongod` instance."
 ---
+name: ":dbcommand:`validate`"
+file: /reference/command/validate
+description: "Internal command that scans for a collection's data and indexes for correctness."
+---
 name: ":dbcommand:`whatsmyuri`"
 file: /reference/command/whatsmyuri
 description: "Internal command that returns information on the current client."
----
-name: ":dbcommand:`getLog`"
-file: /reference/command/getLog
-description: "Returns recent log messages."
----
-name: ":dbcommand:`hostInfo`"
-file: /reference/command/hostInfo
-description: "Returns data that reflects the underlying host system."
----
-name: ":dbcommand:`serverStatus`"
-file: /reference/command/serverStatus
-description: "Returns a collection metrics on instance-wide resource utilization and status."
----
-name: ":dbcommand:`features`"
-file: /reference/command/features
-description: "Reports on features available in the current MongoDB instance."
----
-name: ":dbcommand:`isSelf`"
-file: /reference/command/isSelf
-description: "Internal command to support testing."
 ...

source/reference/command/dbStats.txt

@@ -77,10 +77,17 @@ Output
 
 .. data:: dbStats.dataSize
 
-   The total size in bytes of the data held in this database including the
-   :term:`padding factor`. The ``scale`` argument affects this
-   value. The :data:`~dbStats.dataSize` will not decrease when :term:`documents
-   <document>` shrink, but will decrease when you remove documents.
+   The total size in bytes of the uncompressed data held in this database. The
+   ``scale`` argument affects this value. The :data:`~dbStats.dataSize` will decrease
+   when you remove :term:`documents <document>`.
+
+   For databases using the :doc:`MMAPv1 </core/mmapv1>` storage engine, ``dataSize`` includes
+   preallocated space and the :term:`padding factor`. The ``dataSize`` will not decrease when
+   documents shrink. 
+
+   For databases using the :ref:`WiredTiger <storage-wiredtiger-compression>` storage engine,
+   ``dataSize`` may be larger than ``storageSize`` if compression is enabled.  The ``dataSize``
+   will decrease when documents shrink.
 
    .. sum of all records not counting deleted records
 
@@ -89,7 +96,9 @@ Output
    The total amount of space in bytes allocated to collections in this database
    for :term:`document` storage. The ``scale`` argument affects this
    value. The :data:`~dbStats.storageSize` does not decrease as you remove or
-   shrink documents.
+   shrink documents. This value may be smaller than ``dataSize`` for databases
+   using the WiredTiger storage engine with :ref:`compression <storage-wiredtiger-compression>`
+   enabled.
 
    .. sum of all extents (no indexes or the $freelist)
    .. include links to eventual documentation of storage management