From 8c0c00aae594b6094b94286bf854da9cac3df3f5 Mon Sep 17 00:00:00 2001
From: John Sully <john@csquare.ca>
Date: Wed, 22 Apr 2020 00:47:49 -0400
Subject: [PATCH] RDB load performance, eliminate useless reads

Former-commit-id: 68e5d1850dbba89a87710968d314cb8c0d3cb562
---
 src/db.cpp     | 13 ++++++++-----
 src/server.cpp |  1 +
 src/server.h   |  2 +-
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/db.cpp b/src/db.cpp
index 65ab93900..b909bf310 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -210,13 +210,14 @@ robj *lookupKeyWriteOrReply(client *c, robj *key, robj *reply) {
     return o;
 }
 
-bool dbAddCore(redisDb *db, robj *key, robj *val) {
+bool dbAddCore(redisDb *db, robj *key, robj *val, bool fAssumeNew = false) {
     serverAssert(!val->FExpires());
     sds copy = sdsdupshared(szFromObj(key));
-    bool fInserted = db->insert(copy, val);
     if (g_pserver->fActiveReplica)
         val->mvcc_tstamp = key->mvcc_tstamp = getMvccTstamp();
 
+    bool fInserted = db->insert(copy, val, fAssumeNew);
+
     if (fInserted)
     {
         if (val->type == OBJ_LIST ||
@@ -307,7 +308,7 @@ int dbMerge(redisDb *db, robj *key, robj *val, int fReplace)
     }
     else
     {
-        return (dbAddCore(db, key, val) == true);
+        return (dbAddCore(db, key, val, true) == true);
     }
 }
 
@@ -2175,10 +2176,12 @@ void redisDb::initialize(int id)
         this->setStorageProvider(g_pserver->m_pstorageFactory->create(id));
 }
 
-bool redisDbPersistentData::insert(char *key, robj *o)
+bool redisDbPersistentData::insert(char *key, robj *o, bool fAssumeNew)
 {
-    ensure(key);
+    if (!fAssumeNew)
+        ensure(key);
     int res = dictAdd(m_pdict, key, o);
+    serverAssert(FImplies(fAssumeNew, res == DICT_OK));
     if (res == DICT_OK)
     {
         if (m_pdbSnapshot != nullptr && m_pdbSnapshot->find_cached_threadsafe(key) != nullptr)
diff --git a/src/server.cpp b/src/server.cpp
index 81b60a119..1f465927c 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -5282,6 +5282,7 @@ void loadDataFromDisk(void) {
             serverLog(LL_NOTICE,"DB loaded from append only file: %.3f seconds",(float)(ustime()-start)/1000000);
     } else if (g_pserver->rdb_filename != NULL || g_pserver->rdb_s3bucketpath != NULL) {
         rdbSaveInfo rsi = RDB_SAVE_INFO_INIT;
+        rsi.fForceSetKey = false;
         if (rdbLoad(&rsi,RDBFLAGS_NONE) == C_OK) {
             serverLog(LL_NOTICE,"DB loaded from disk: %.3f seconds",
                 (float)(ustime()-start)/1000000);
diff --git a/src/server.h b/src/server.h
index c35f3e91a..0c7d0f63b 100644
--- a/src/server.h
+++ b/src/server.h
@@ -1276,7 +1276,7 @@ public:
     void getStats(char *buf, size_t bufsize) { dictGetStats(buf, bufsize, m_pdict); }
     void getExpireStats(char *buf, size_t bufsize) { m_setexpire->getstats(buf, bufsize); }
 
-    bool insert(char *k, robj *o);
+    bool insert(char *k, robj *o, bool fAssumeNew = false);
     void tryResize();
     int incrementallyRehash();
     void updateValue(dict_iter itr, robj *val);