configure "Wal" for sqlite

meshview/mqtt_database.py

@@ -1,16 +1,32 @@
 from sqlalchemy.engine.url import make_url
 from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+from sqlalchemy import event
 
 from meshview import models
 
 
 def init_database(database_connection_string):
     global engine, async_session
+
     url = make_url(database_connection_string)
     kwargs = {"echo": False}
+
     if url.drivername.startswith("sqlite"):
-        kwargs["connect_args"] = {"timeout": 900}
+        kwargs["connect_args"] = {"timeout": 900}  # seconds
+
     engine = create_async_engine(url, **kwargs)
+
+    # Enforce SQLite pragmas on every new DB connection
+    if url.drivername.startswith("sqlite"):
+
+        @event.listens_for(engine.sync_engine, "connect")
+        def _set_sqlite_pragmas(dbapi_conn, _):
+            cursor = dbapi_conn.cursor()
+            cursor.execute("PRAGMA journal_mode=WAL;")
+            cursor.execute("PRAGMA busy_timeout=900000;")  # ms
+            cursor.execute("PRAGMA synchronous=NORMAL;")
+            cursor.close()
+
     async_session = async_sessionmaker(engine, expire_on_commit=False)