From 9cbdfb3a2f501a4eaa68981d836005d6d8257295 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Thu, 23 Apr 2020 15:45:12 +0100
Subject: [PATCH] Make it clear that the limit for an update_function is a
target
---
synapse/replication/tcp/streams/_base.py | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index 112bfead56..4ae3cffb1e 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -24,8 +24,8 @@ from synapse.replication.http.streams import ReplicationGetStreamUpdates
logger = logging.getLogger(__name__)
-
-MAX_EVENTS_BEHIND = 500000
+# the number of rows to request from an update_function.
+_STREAM_UPDATE_TARGET_ROW_COUNT = 100
# Some type aliases to make things a bit easier.
@@ -56,7 +56,11 @@ StreamUpdateResult = Tuple[List[Tuple[Token, StreamRow]], Token, bool]
# * from_token: the previous stream token: the starting point for fetching the
# updates
# * to_token: the new stream token: the point to get updates up to
-# * limit: the maximum number of rows to return
+# * target_row_count: a target for the number of rows to be returned.
+#
+# The update_function is expected to return up to _approximately_ target_row_count rows.
+# If there are more updates available, it should set `limited` in the result, and
+# it will be called again to get the next batch.
#
UpdateFunction = Callable[[Token, Token, int], Awaitable[StreamUpdateResult]]
@@ -138,7 +142,7 @@ class Stream(object):
return updates, current_token, limited
async def get_updates_since(
- self, from_token: Token, upto_token: Token, limit: int = 100
+ self, from_token: Token, upto_token: Token
) -> StreamUpdateResult:
"""Like get_updates except allows specifying from when we should
stream updates
@@ -156,7 +160,7 @@ class Stream(object):
return [], upto_token, False
updates, upto_token, limited = await self.update_function(
- from_token, upto_token, limit,
+ from_token, upto_token, _STREAM_UPDATE_TARGET_ROW_COUNT,
)
return updates, upto_token, limited
--
GitLab