googleapis · vi3k6i5 · Feb 28, 2022 · Oct 21, 2021 · Feb 28, 2022 · Feb 28, 2022
diff --git a/README.rst b/README.rst
@@ -246,4 +246,7 @@ Spanner has certain limitations of its own. The full set of limitations is docum
 It is recommended that you go through that list.
 
 Django spanner has a set of limitations as well, which you can find
-`here <https://github.com/googleapis/python-spanner-django/blob/main/docs/limitations.rst>`__.
+`here <https://github.com/googleapis/python-spanner-django/blob/main/docs/limitations.rst>`__.
+
+Features from spanner that are not supported in Django-spanner are listed 
+`here <https://github.com/googleapis/python-spanner-django/blob/main/docs/limitations-spanner.rst>`__.
diff --git a/docs/limitations-spanner.rst b/docs/limitations-spanner.rst
@@ -0,0 +1,112 @@
+Limitations from Spanner perspective
+------------------------------------
+
+Below is a List of Limitations for features that are supported in Spanner but 
+are not supported in the Django Spanner library. Some features have been 
+disabled because of compatibility issues using the Django feature toggle.
+
+Query Hints
+~~~~~~~~~~~
+Django automatically manages query generation and thus does not expose methods
+to add query hints directly. While libraries can add support for this feature 
+and manage the query generation part, we have not added this because of the 
+added complexity. The workaround to use this feature is by using Raw Queries 
+directly, and adding Query hints there.
+
+Mutations
+~~~~~~~~~
+Mutations are not a concept that is understood by Django so it does not support
+it inherently. The workaround is to use python-spanner objects and run Mutations using that.
+
+Batch DDL
+~~~~~~~~~
+Migrations (creation and updation) of tables in Django are sequential operations. 
+Django doesn't inherently support doing batch DDL operations. However, customers 
+can use python-spanner objects to run batch DDL for unmanaged tables in Django.
+
+Stale Reads
+~~~~~~~~~~~
+Stale Reads are not a concept that is understood by Django so it does not support 
+it inherently. The workaround is to use python-spanner objects and run read operations on snapshots.
+
+Interleaving
+~~~~~~~~~~~~
+Interleaving is not a concept that is understood by Django so it does not support 
+it inherently. The workaround is to use Unmanaged tables and python-spanner objects 
+to create and manage interleaved tables.
+
+
+Partitioned DML
+~~~~~~~~~~~~~~~
+Partitioned DML is not a concept that is understood by Django so it does not support 
+it inherently. The workaround is to use python-spanner objects to perform partitioned 
+DML operations.
+
+Session Labeling
+~~~~~~~~~~~~~~~~
+Django does not support session pools for databases directly and does not have the 
+concept of session labeling itself. The workaround is to use python-spanner objects 
+to create and manage sessions along with Session labels.
+
+Request Priority
+~~~~~~~~~~~~~~~~
+Request Priority for database calls is not a concept that is understood by Django so 
+it does not support it inherently. The workaround is to use python-spanner objects 
+and use request priority as part of the db calls.
+
+Tagging
+~~~~~~~
+Tagging for database calls is not a concept that is understood by Django so it does not 
+support it inherently. The workaround is to use python-spanner objects and use the 
+tagging feature via that.
+
+Configurable Leader Option
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+Configuring Leader Option for database calls is not a concept that is understood by 
+Django so it does not support it inherently. The workaround is to use python-spanner 
+objects while creating the database.
+
+Backups / Cross region Backups
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Backups for databases are not managed by Django so it does not support it inherently. 
+In general, none of the Spanner ORMs / drivers are expected to support backup management.
+The workaround is to use python-spanner objects and use backup features via that.
+
+Custom Instance Config
+~~~~~~~~~~~~~~~~~~~~~~
+Instances for spanner are not managed by Django so it does not support it inherently. 
+The workaround is to use python-spanner objects and use Instance config features via that.
+
+Workaround
+----------
+
+.. list-table::
+   :widths: 33 67
+   :header-rows: 1
+
+   * - Features
+     - Is a workaround available?
+   * - Query Hints
+     - Raw Queries can be used for Query hints `Link <https://stackoverflow.com/a/28350704/3027854>`__.
+   * - Mutations
+     - Python-spanner database objects can be used to run Mutation queries. `Link <https://cloud.google.com/spanner/docs/modify-mutation-api#python>`__.
+   * - Batch DDL
+     - Using unmanaged tables in Django. `Link <https://docs.djangoproject.com/en/4.0/ref/models/options/#managed>`__ and Directly using Python spanner objects to execute batch DDL statements. `Link <https://cloud.google.com/spanner/docs/getting-started/python#create_a_database>`__.
+   * - Stale Reads
+     - Python-spanner database objects can be used to perform stale reads. `Link <https://cloud.google.com/spanner/docs/reads#python>`__.
+   * - Interleaving
+     - Using unmanaged tables in Django. `Link <https://docs.djangoproject.com/en/4.0/ref/models/options/#managed>`__ and Directly using Python spanner objects to create interleaved tables. `Link <https://cloud.google.com/spanner/docs/getting-started/python#create_a_database>`__.
+   * - Partitioned DML
+     - Python-spanner database objects can be used to perform Partitioned DML. `Link <https://cloud.google.com/spanner/docs/dml-partitioned#python>`__.
+   * - Session Labeling
+     - Python-spanner connection objects can be used to perform Session creation and labeling . `Link <https://cloud.google.com/spanner/docs/sessions#python>`__.
+   * - Request Priority
+     - Python-spanner connection objects can be used to make backend calls with request priority. `Link <https://cloud.google.com/spanner/docs/reference/rest/v1/RequestOptions>`__.
+   * - Tagging
+     - Python-spanner connection objects can be used to make backend calls with request tags. `Link <https://cloud.google.com/spanner/docs/reference/rest/v1/RequestOptions>`__.
+   * - Configurable Leader Option
+     - Python-spanner database objects can be used to set or update leader options. `Link <https://cloud.google.com/spanner/docs/modifying-leader-region#python>`__.
+   * - Cross region backup
+     - Python-spanner library can be used to perform db backups across regions. `Link <https://cloud.google.com/spanner/docs/backup>`__.
+   * - Custom Instance Config
+     - Python-spanner library can be used to manage instances. `Link <https://googleapis.dev/python/spanner/latest/instance-api.html>`__.