From 160bce9aff9ba33615bba93d73655ca6afdef3d2 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Fri, 1 May 2020 09:25:16 +0100
Subject: [PATCH] Workaround for assertion errors from
 db_query_to_update_function (#7378)

Hopefully this is no worse than what we have on master...
---
 changelog.d/7378.misc                    | 1 +
 synapse/replication/tcp/streams/_base.py | 3 +--
 2 files changed, 2 insertions(+), 2 deletions(-)
 create mode 100644 changelog.d/7378.misc

diff --git a/changelog.d/7378.misc b/changelog.d/7378.misc
new file mode 100644
index 000000000000..676f285377f5
--- /dev/null
+++ b/changelog.d/7378.misc
@@ -0,0 +1 @@
+Move catchup of replication streams logic to worker.
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index 4ae3cffb1e14..4af1afd119ca 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -176,10 +176,9 @@ async def update_function(from_token, upto_token, limit):
         rows = await query_function(from_token, upto_token, limit)
         updates = [(row[0], row[1:]) for row in rows]
         limited = False
-        if len(updates) == limit:
+        if len(updates) >= limit:
             upto_token = updates[-1][0]
             limited = True
-        assert len(updates) <= limit
 
         return updates, upto_token, limited