non-blocking history lookup in notify

lbry/wallet/server/session.py

@@ -922,36 +922,27 @@ class LBRYElectrumX(SessionBase):
             args = (await self.subscribe_headers_result(), )
             if not (await self.send_notification('blockchain.headers.subscribe', args)):
                 return
+
+        async def send_history_notification(alias, hashX):
+            if len(alias) == 64:
+                method = 'blockchain.scripthash.subscribe'
+            else:
+                method = 'blockchain.address.subscribe'
+            status = await self.address_status(hashX)
+            await self.send_notification(method, (alias, status))
+
         touched = touched.intersection(self.hashX_subs)
         if touched or (height_changed and self.mempool_statuses):
-            changed = {}
-
             for hashX in touched:
                 alias = self.hashX_subs[hashX]
-                status = await self.address_status(hashX)
+                asyncio.create_task(send_history_notification(alias, hashX))
-                changed[alias] = status
+
+            if touched:
+                es = '' if len(touched) == 1 else 'es'
+                self.logger.info(f'notified of {len(touched):,d} address{es}')
+
 
-            # Check mempool hashXs - the status is a function of the
-            # confirmed state of other transactions.  Note: we cannot
-            # iterate over mempool_statuses as it changes size.
-            for hashX in tuple(self.mempool_statuses):
-                # Items can be evicted whilst await-ing status; False
-                # ensures such hashXs are notified
-                old_status = self.mempool_statuses.get(hashX, False)
-                status = await self.address_status(hashX)
-                if status != old_status:
-                    alias = self.hashX_subs[hashX]
-                    changed[alias] = status
 
-            for alias, status in changed.items():
-                if len(alias) == 64:
-                    method = 'blockchain.scripthash.subscribe'
-                else:
-                    method = 'blockchain.address.subscribe'
-                asyncio.create_task(self.send_notification(method, (alias, status)))
-            if changed:
-                es = '' if len(changed) == 1 else 'es'
-                self.logger.info(f'notified of {len(changed):,d} address{es}')
 
     def get_metrics_or_placeholder_for_api(self, query_name):
         """ Do not hold on to a reference to the metrics