From a4c1bcefb9d2a6f2aa0bc189fca496d46c78e3b0 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Tue, 17 May 2022 18:12:15 -0500
Subject: [PATCH] Tune sqlite based on configured settings (#72016)

---
 homeassistant/components/recorder/util.py | 14 ++++-
 tests/components/recorder/test_util.py    | 64 ++++++++++++++++++++---
 2 files changed, 70 insertions(+), 8 deletions(-)

diff --git a/homeassistant/components/recorder/util.py b/homeassistant/components/recorder/util.py
index eb99c304808..e464ac4126b 100644
--- a/homeassistant/components/recorder/util.py
+++ b/homeassistant/components/recorder/util.py
@@ -426,8 +426,18 @@ def setup_connection_for_dialect(
                     version or version_string, "SQLite", MIN_VERSION_SQLITE
                 )
 
-        # approximately 8MiB of memory
-        execute_on_connection(dbapi_connection, "PRAGMA cache_size = -8192")
+        # The upper bound on the cache size is approximately 16MiB of memory
+        execute_on_connection(dbapi_connection, "PRAGMA cache_size = -16384")
+
+        #
+        # Enable FULL synchronous if they have a commit interval of 0
+        # or NORMAL if they do not.
+        #
+        # https://sqlite.org/pragma.html#pragma_synchronous
+        # The synchronous=NORMAL setting is a good choice for most applications running in WAL mode.
+        #
+        synchronous = "NORMAL" if instance.commit_interval else "FULL"
+        execute_on_connection(dbapi_connection, f"PRAGMA synchronous={synchronous}")
 
         # enable support for foreign keys
         execute_on_connection(dbapi_connection, "PRAGMA foreign_keys=ON")
diff --git a/tests/components/recorder/test_util.py b/tests/components/recorder/test_util.py
index c650ec20fb0..fea255647ec 100644
--- a/tests/components/recorder/test_util.py
+++ b/tests/components/recorder/test_util.py
@@ -234,18 +234,70 @@ def test_setup_connection_for_dialect_sqlite(sqlite_version, db_supports_row_num
 
     util.setup_connection_for_dialect(instance_mock, "sqlite", dbapi_connection, True)
 
-    assert len(execute_args) == 4
+    assert len(execute_args) == 5
     assert execute_args[0] == "PRAGMA journal_mode=WAL"
     assert execute_args[1] == "SELECT sqlite_version()"
-    assert execute_args[2] == "PRAGMA cache_size = -8192"
-    assert execute_args[3] == "PRAGMA foreign_keys=ON"
+    assert execute_args[2] == "PRAGMA cache_size = -16384"
+    assert execute_args[3] == "PRAGMA synchronous=NORMAL"
+    assert execute_args[4] == "PRAGMA foreign_keys=ON"
 
     execute_args = []
     util.setup_connection_for_dialect(instance_mock, "sqlite", dbapi_connection, False)
 
-    assert len(execute_args) == 2
-    assert execute_args[0] == "PRAGMA cache_size = -8192"
-    assert execute_args[1] == "PRAGMA foreign_keys=ON"
+    assert len(execute_args) == 3
+    assert execute_args[0] == "PRAGMA cache_size = -16384"
+    assert execute_args[1] == "PRAGMA synchronous=NORMAL"
+    assert execute_args[2] == "PRAGMA foreign_keys=ON"
+
+    assert instance_mock._db_supports_row_number == db_supports_row_number
+
+
+@pytest.mark.parametrize(
+    "sqlite_version, db_supports_row_number",
+    [
+        ("3.25.0", True),
+        ("3.24.0", False),
+    ],
+)
+def test_setup_connection_for_dialect_sqlite_zero_commit_interval(
+    sqlite_version, db_supports_row_number
+):
+    """Test setting up the connection for a sqlite dialect with a zero commit interval."""
+    instance_mock = MagicMock(_db_supports_row_number=True, commit_interval=0)
+    execute_args = []
+    close_mock = MagicMock()
+
+    def execute_mock(statement):
+        nonlocal execute_args
+        execute_args.append(statement)
+
+    def fetchall_mock():
+        nonlocal execute_args
+        if execute_args[-1] == "SELECT sqlite_version()":
+            return [[sqlite_version]]
+        return None
+
+    def _make_cursor_mock(*_):
+        return MagicMock(execute=execute_mock, close=close_mock, fetchall=fetchall_mock)
+
+    dbapi_connection = MagicMock(cursor=_make_cursor_mock)
+
+    util.setup_connection_for_dialect(instance_mock, "sqlite", dbapi_connection, True)
+
+    assert len(execute_args) == 5
+    assert execute_args[0] == "PRAGMA journal_mode=WAL"
+    assert execute_args[1] == "SELECT sqlite_version()"
+    assert execute_args[2] == "PRAGMA cache_size = -16384"
+    assert execute_args[3] == "PRAGMA synchronous=FULL"
+    assert execute_args[4] == "PRAGMA foreign_keys=ON"
+
+    execute_args = []
+    util.setup_connection_for_dialect(instance_mock, "sqlite", dbapi_connection, False)
+
+    assert len(execute_args) == 3
+    assert execute_args[0] == "PRAGMA cache_size = -16384"
+    assert execute_args[1] == "PRAGMA synchronous=FULL"
+    assert execute_args[2] == "PRAGMA foreign_keys=ON"
 
     assert instance_mock._db_supports_row_number == db_supports_row_number