Added transaction protection

src/main.py

@@ -359,7 +359,7 @@ def delete_feed(
 	try:
 		with db.cursor() as cursor:
 			cursor.execute(
-				"SELECT id FROM rss_feeds WHERE rss_feed = %s",
+				"SELECT id FROM rss_feeds WHERE rss_feed = %s FOR UPDATE",
 				(url,),
 			)
 			known = cursor.fetchone()
@@ -377,7 +377,7 @@ def delete_feed(
 
 			cursor.execute(
 				"SELECT 1 from rss_feed_subscriptions "
-				"WHERE rss_feed_id = %s AND active = 1 LIMIT 1",
+				"WHERE rss_feed_id = %s AND active = 1 LIMIT 1 FOR SHARE",
 				(feed_id,),
 			)
 			if cursor.fetchone() is None: