Merge branch 'master' into release-lifecycle-updates

source/install/prepare-mattermost-database.rst

@@ -207,3 +207,7 @@ To set up a PostgreSQL database for use by the Mattermost server:
 The PostgreSQL interactive terminal starts. To exit the PostgreSQL interactive terminal, type ``\q`` and press :kbd:`Enter` on Windows or Linux, or :kbd:`↵` on Mac.
 
 When the PostgreSQL database is installed, and the initial setup is complete, you can install the Mattermost server.
+
+### Important note while upgrading a Postgres instance
+
+If you are upgrading a major version of Postgres, it is essential that ``ANALYZE VERBOSE`` is run on the database post upgrade. This is necessary to re-populate the ``pg_statistics`` table used to generate optimal query plans. The database performance might suffer if this step is not done.