RDB: refactor some RDB loading code into dbAddRDBLoad().

src/db.c

@@ -188,6 +188,24 @@ void dbAdd(redisDb *db, robj *key, robj *val) {
     if (server.cluster_enabled) slotToKeyAdd(key->ptr);
 }
 
+/* This is a special version of dbAdd() that is used only when loading
+ * keys from the RDB file: the key is passed as an SDS string that is
+ * retained by the function (and not freed by the caller).
+ *
+ * Moreover this function will not abort if the key is already busy, to
+ * give more control to the caller, nor will signal the key as ready
+ * since it is not useful in this context.
+ *
+ * The function returns 1 if the key was added to the database, taking
+ * ownership of the SDS string, otherwise 0 is returned, and is up to the
+ * caller to free the SDS string. */
+int dbAddRDBLoad(redisDb *db, sds key, robj *val) {
+    int retval = dictAdd(db->dict, key, val);
+    if (retval != DICT_OK) return 0;
+    if (server.cluster_enabled) slotToKeyAdd(key);
+    return 1;
+}
+
 /* Overwrite an existing key with a new value. Incrementing the reference
  * count of the new value is up to the caller.
  * This function does not modify the expire time of the existing key.

src/rdb.c

@@ -2245,22 +2245,21 @@ int rdbLoadRio(rio *rdb, int rdbflags, rdbSaveInfo *rsi) {
             robj keyobj;
 
             /* Add the new object in the hash table */
-            int retval = dictAdd(db->dict, key, val);
+            int added = dbAddRDBLoad(db,key,val);
-            if (retval != DICT_OK) {
+            if (!added) {
                 if (rdbflags & RDBFLAGS_ALLOW_DUP) {
                     /* This flag is useful for DEBUG RELOAD special modes.
                      * When it's set we allow new keys to replace the current
                      * keys with the same name. */
                     initStaticStringObject(keyobj,key);
                     dbSyncDelete(db,&keyobj);
-                    dictAdd(db->dict, key, val);
+                    dbAddRDBLoad(db,key,val);
                 } else {
                     serverLog(LL_WARNING,
                         "RDB has duplicated key '%s' in DB %d",key,db->id);
                     serverPanic("Duplicated key found in RDB file");
                 }
             }
-            if (server.cluster_enabled) slotToKeyAdd(key);
 
             /* Set the expire time if needed */
             if (expiretime != -1) {

src/server.h

@@ -2069,6 +2069,7 @@ int objectSetLRUOrLFU(robj *val, long long lfu_freq, long long lru_idle,
 #define LOOKUP_NONE 0
 #define LOOKUP_NOTOUCH (1<<0)
 void dbAdd(redisDb *db, robj *key, robj *val);
+int dbAddRDBLoad(redisDb *db, sds key, robj *val);
 void dbOverwrite(redisDb *db, robj *key, robj *val);
 void genericSetKey(redisDb *db, robj *key, robj *val, int keepttl, int signal);
 void setKey(redisDb *db, robj *key, robj *val);