remove expensive sql request, python set comparison is faster

electrum/lnrouter.py

@@ -41,7 +41,7 @@ from sqlalchemy.orm.query import Query
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.sql import not_, or_
 
-from .sql_db import SqlDB, sql, SQLITE_LIMIT_VARIABLE_NUMBER
+from .sql_db import SqlDB, sql
 from . import constants
 from .util import bh2u, profiler, get_headers_dir, bfh, is_ip_address, list_enabled_bits, print_msg, chunks
 from .logging import Logger
@@ -228,18 +228,9 @@ class ChannelDB(SqlDB):
         self.num_nodes = self.DBSession.query(NodeInfo).count()
 
     @sql
-    @profiler
-    def compare_channels(self, channel_ids):
-        ids = [x.hex() for x in channel_ids]
-        known = set()
-        # I need to get the unknown, and also the channels that need refresh
-        for ids_chunk in chunks(ids, SQLITE_LIMIT_VARIABLE_NUMBER):
-            known_part = self.DBSession \
-                     .query(ChannelInfo) \
-                     .filter(ChannelInfo.short_channel_id.in_(ids_chunk)) \
-                     .all()
-            known |= set(bfh(r.short_channel_id) for r in known_part)
-        return known
+    def known_ids(self):
+        known = self.DBSession.query(ChannelInfo.short_channel_id).all()
+        return set(bfh(r.short_channel_id) for r in known)
 
     @sql
     def add_recent_peer(self, peer: LNPeerAddr):

electrum/lnworker.py

@@ -274,7 +274,7 @@ class LNGossip(LNWorker):
             await asyncio.sleep(5)
 
     def add_new_ids(self, ids):
-        known = self.channel_db.compare_channels(ids)
+        known = self.channel_db.known_ids()
         new = set(ids) - set(known)
         self.unknown_ids.update(new)