Disable fastsync by default

Author: JohnSully

src/config.cpp

@@ -2983,7 +2983,7 @@ standardConfig configs[] = {
     createIntConfig("overload-protect-percent", NULL, MODIFIABLE_CONFIG, 0, 200, g_pserver->overload_protect_threshold, 0, INTEGER_CONFIG, NULL, NULL),
     createIntConfig("force-eviction-percent", NULL, MODIFIABLE_CONFIG, 0, 100, g_pserver->force_eviction_percent, 0, INTEGER_CONFIG, NULL, NULL),
     createBoolConfig("enable-async-rehash", NULL, MODIFIABLE_CONFIG, g_pserver->enable_async_rehash, 1, NULL, NULL),
-    createBoolConfig("enable-keydb-fastsync", NULL, MODIFIABLE_CONFIG, g_pserver->fEnableFastSync, 1, NULL, NULL),
+    createBoolConfig("enable-keydb-fastsync", NULL, MODIFIABLE_CONFIG, g_pserver->fEnableFastSync, 0, NULL, NULL),
 
 #ifdef USE_OPENSSL
     createIntConfig("tls-port", NULL, MODIFIABLE_CONFIG, 0, 65535, g_pserver->tls_port, 0, INTEGER_CONFIG, NULL, updateTLSPort), /* TCP port. */

src/server.h

@@ -2687,7 +2687,7 @@ struct redisServer {
 
     int fActiveReplica;                          /* Can this replica also be a master? */
     int fWriteDuringActiveLoad;                  /* Can this active-replica write during an RDB load? */
-    int fEnableFastSync = true;
+    int fEnableFastSync = false;
 
     // Format:
     //  Lower 20 bits: a counter incrementing for each command executed in the same millisecond