From 3294e4f7884df12d7c88bc934431961b10781187 Mon Sep 17 00:00:00 2001
From: John Sully <john@csquare.ca>
Date: Thu, 23 Sep 2021 17:45:49 +0000
Subject: [PATCH] Move the snapshot stale threshold to a named constant

Former-commit-id: 46d2aaf17abb0fb021aa6d7b393ffc143493d339
---
 src/server.h     | 3 +++
 src/snapshot.cpp | 4 +---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/server.h b/src/server.h
index 819690b62..482be14a3 100644
--- a/src/server.h
+++ b/src/server.h
@@ -1263,6 +1263,8 @@ public:
     // These need to be fixed
     using redisDbPersistentData::size;
     using redisDbPersistentData::expireSize;
+
+    static const uint64_t msStaleThreshold = 500;
 };
 
 /* Redis database representation. There are multiple databases identified
@@ -1350,6 +1352,7 @@ public:
     long long last_expire_set;  /* when the last expire was set */
     double avg_ttl;             /* Average TTL, just for stats */
     list *defrag_later;         /* List of key names to attempt to defrag one by one, gradually. */
+    uint64_t mvccLastSnapshot = 0;
 };
 
 /* Declare database backup that include redis main DBs and slots to keys map.
diff --git a/src/snapshot.cpp b/src/snapshot.cpp
index 795df287d..a13f5d9f5 100644
--- a/src/snapshot.cpp
+++ b/src/snapshot.cpp
@@ -654,9 +654,7 @@ int redisDbPersistentDataSnapshot::snapshot_depth() const
 
 bool redisDbPersistentDataSnapshot::FStale() const
 {
-    // 0.5 seconds considered stale;
-    static const uint64_t msStale = 500;
-    return ((getMvccTstamp() - m_mvccCheckpoint) >> MVCC_MS_SHIFT) >= msStale;
+    return ((getMvccTstamp() - m_mvccCheckpoint) >> MVCC_MS_SHIFT) >= redisDbPersistentDataSnapshot::msStaleThreshold;
 }
 
 void dictGCAsyncFree(dictAsyncRehashCtl *async) {