From b666962ed83d0870cc96b90b00a158dbf176c3d7 Mon Sep 17 00:00:00 2001
From: John Sully <john@csquare.ca>
Date: Fri, 12 Nov 2021 00:18:32 +0000
Subject: [PATCH] Allow fast sync even if a background save is in progress

Former-commit-id: b98aadfb6875f366a63a9d27d47fb5ca60abaa03
---
 src/replication.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/replication.cpp b/src/replication.cpp
index 3651b0113..2618a605f 100644
--- a/src/replication.cpp
+++ b/src/replication.cpp
@@ -1385,8 +1385,11 @@ void syncCommand(client *c) {
                             g_pserver->replid, g_pserver->replid2);
     }
 
+    /* CASE 0: Fast Sync */
+    if ((c->slave_capa & SLAVE_CAPA_ROCKSDB_SNAPSHOT) && g_pserver->m_pstorageFactory) {
+        startBgsaveForReplication(c->slave_capa);
     /* CASE 1: BGSAVE is in progress, with disk target. */
-    if (g_pserver->FRdbSaveInProgress() &&
+    } else if (g_pserver->FRdbSaveInProgress() &&
         g_pserver->rdb_child_type == RDB_CHILD_TYPE_DISK)
     {
         /* Ok a background save is in progress. Let's check if it is a good