From a94eb716304989d4e0460ea98f99ebfb87b307e7 Mon Sep 17 00:00:00 2001
From: sergekh2 <104387024+sergekh2@users.noreply.github.com>
Date: Mon, 1 Aug 2022 11:28:00 -0700
Subject: [PATCH] Fix issue with sync API not advancing.

Issue: During conversation, under some conditions, sync cookie is not advanced, and, as a result, client loops on the same sync API call creating high traffic and CPU load.
Fix: pdu component of cookie was updated incorrectly.
---
 syncapi/streams/stream_pdu.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/syncapi/streams/stream_pdu.go b/syncapi/streams/stream_pdu.go
index 1832adbe5..1003208fd 100644
--- a/syncapi/streams/stream_pdu.go
+++ b/syncapi/streams/stream_pdu.go
@@ -261,9 +261,9 @@ func (p *PDUStreamProvider) addRoomDeltaToResponse(
 		var pos types.StreamPosition
 		if _, pos, err = p.DB.PositionInTopology(ctx, mostRecentEventID); err == nil {
 			switch {
-			case r.Backwards && pos > latestPosition:
+			case r.Backwards && pos < latestPosition:
 				fallthrough
-			case !r.Backwards && pos < latestPosition:
+			case !r.Backwards && pos > latestPosition:
 				latestPosition = pos
 			}
 		}