From 7a05b8a2fac57e32a61726893d4601352c1d1c8d Mon Sep 17 00:00:00 2001
From: Aaron Linville <aaron@linville.org>
Date: Thu, 17 Aug 2023 18:06:25 -0400
Subject: [PATCH] Fixed #24018 -- Allowed setting pragma options on SQLite.

---
 AUTHORS                            |  1 +
 django/db/backends/sqlite3/base.py |  6 ++++++
 docs/ref/databases.txt             | 24 ++++++++++++++++++++++++
 docs/releases/5.1.txt              |  7 +++++++
 docs/spelling_wordlist             |  1 +
 tests/backends/sqlite/tests.py     | 23 +++++++++++++++++++++++
 6 files changed, 62 insertions(+)

diff --git a/AUTHORS b/AUTHORS
index 6fef75cf43..945a017cf8 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -6,6 +6,7 @@ people who have submitted patches, reported bugs, added translations, helped
 answer newbie questions, and generally made Django that much better:
 
     Aaron Cannon <cannona@fireantproductions.com>
+    Aaron Linville <aaron@linville.org>
     Aaron Swartz <http://www.aaronsw.com/>
     Aaron T. Myers <atmyers@gmail.com>
     Abeer Upadhyay <ab.esquarer@gmail.com>
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index 8e17ea3d44..c7cf947800 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -187,6 +187,9 @@ class DatabaseWrapper(BaseDatabaseWrapper):
                 f"{allowed_transaction_modes}, or None."
             )
         self.transaction_mode = transaction_mode.upper() if transaction_mode else None
+
+        init_command = kwargs.pop("init_command", "")
+        self.init_commands = init_command.split(";")
         return kwargs
 
     def get_database_version(self):
@@ -201,6 +204,9 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         # The macOS bundled SQLite defaults legacy_alter_table ON, which
         # prevents atomic table renames.
         conn.execute("PRAGMA legacy_alter_table = OFF")
+        for init_command in self.init_commands:
+            if init_command := init_command.strip():
+                conn.execute(init_command)
         return conn
 
     def create_cursor(self, name=None):
diff --git a/docs/ref/databases.txt b/docs/ref/databases.txt
index d853647730..1bc787671e 100644
--- a/docs/ref/databases.txt
+++ b/docs/ref/databases.txt
@@ -941,6 +941,30 @@ To enable the JSON1 extension you can follow the instruction on
 .. _JSON1 extension: https://www.sqlite.org/json1.html
 .. _the wiki page: https://code.djangoproject.com/wiki/JSON1Extension
 
+.. _sqlite-init-command:
+
+Setting pragma options
+----------------------
+
+.. versionadded:: 5.1
+
+`Pragma options`_ can be set upon connection by using the ``init_command`` in
+the :setting:`OPTIONS` part of your database configuration in
+:setting:`DATABASES`. The example below shows how to enable extra durability of
+synchronous writes and change the ``cache_size``::
+
+    DATABASES = {
+        "default": {
+            "ENGINE": "django.db.backends.sqlite3",
+            # ...
+            "OPTIONS": {
+                "init_command": "PRAGMA synchronous=3; PRAGMA cache_size=2000;",
+            },
+        }
+    }
+
+.. _Pragma options: https://www.sqlite.org/pragma.html
+
 .. _oracle-notes:
 
 Oracle notes
diff --git a/docs/releases/5.1.txt b/docs/releases/5.1.txt
index 94c342e8a0..e288bab20c 100644
--- a/docs/releases/5.1.txt
+++ b/docs/releases/5.1.txt
@@ -146,6 +146,13 @@ CSRF
 
 * ...
 
+Database backends
+~~~~~~~~~~~~~~~~~
+
+* ``"init_command"`` option is now supported in :setting:`OPTIONS` on SQLite
+  to allow specifying :ref:`pragma options <sqlite-init-command>` to set upon
+  connection.
+
 Decorators
 ~~~~~~~~~~
 
diff --git a/docs/spelling_wordlist b/docs/spelling_wordlist
index 5828b24253..1044cd80eb 100644
--- a/docs/spelling_wordlist
+++ b/docs/spelling_wordlist
@@ -361,6 +361,7 @@ postfix
 postgis
 postgres
 postgresql
+pragma
 pre
 precisions
 precomputation
diff --git a/tests/backends/sqlite/tests.py b/tests/backends/sqlite/tests.py
index 42fee432f9..91dd83f134 100644
--- a/tests/backends/sqlite/tests.py
+++ b/tests/backends/sqlite/tests.py
@@ -116,6 +116,29 @@ class Tests(TestCase):
             connection.check_database_version_supported()
         self.assertTrue(mocked_get_database_version.called)
 
+    def test_init_command(self):
+        settings_dict = {
+            "default": {
+                "ENGINE": "django.db.backends.sqlite3",
+                "NAME": ":memory:",
+                "OPTIONS": {
+                    "init_command": "PRAGMA synchronous=3; PRAGMA cache_size=2000;",
+                },
+            }
+        }
+        connections = ConnectionHandler(settings_dict)
+        connections["default"].ensure_connection()
+        try:
+            with connections["default"].cursor() as cursor:
+                cursor.execute("PRAGMA synchronous")
+                value = cursor.fetchone()[0]
+                self.assertEqual(value, 3)
+                cursor.execute("PRAGMA cache_size")
+                value = cursor.fetchone()[0]
+                self.assertEqual(value, 2000)
+        finally:
+            connections["default"].close()
+
 
 @unittest.skipUnless(connection.vendor == "sqlite", "SQLite tests")
 @isolate_apps("backends")