1 files changed, 18 insertions, 11 deletions

diff --git a/src/rdb.c b/src/rdb.c
index 2689b172d..1a5a7b2c5 100644
--- a/src/rdb.c
+++ b/src/rdb.c
@@ -704,23 +704,30 @@ ssize_t rdbSaveObject(rio *rdb, robj *o) {
             nwritten += n;
         } else if (o->encoding == OBJ_ENCODING_SKIPLIST) {
             zset *zs = o->ptr;
-            dictIterator *di = dictGetIterator(zs->dict);
-            dictEntry *de;
+            zskiplist *zsl = zs->zsl;
 
-            if ((n = rdbSaveLen(rdb,dictSize(zs->dict))) == -1) return -1;
+            if ((n = rdbSaveLen(rdb,zsl->length)) == -1) return -1;
             nwritten += n;
 
-            while((de = dictNext(di)) != NULL) {
-                sds ele = dictGetKey(de);
-                double *score = dictGetVal(de);
-
-                if ((n = rdbSaveRawString(rdb,(unsigned char*)ele,sdslen(ele)))
-                    == -1) return -1;
+            /* We save the skiplist elements from the greatest to the smallest
+             * (that's trivial since the elements are already ordered in the
+             * skiplist): this improves the load process, since the next loaded
+             * element will always be the smaller, so adding to the skiplist
+             * will always immediately stop at the head, making the insertion
+             * O(1) instead of O(log(N)). */
+            zskiplistNode *zn = zsl->tail;
+            while (zn != NULL) {
+                if ((n = rdbSaveRawString(rdb,
+                    (unsigned char*)zn->ele,sdslen(zn->ele))) == -1)
+                {
+                    return -1;
+                }
                 nwritten += n;
-                if ((n = rdbSaveBinaryDoubleValue(rdb,*score)) == -1) return -1;
+                if ((n = rdbSaveBinaryDoubleValue(rdb,zn->score)) == -1)
+                    return -1;
                 nwritten += n;
+                zn = zn->backward;
             }
-            dictReleaseIterator(di);
         } else {
             serverPanic("Unknown sorted set encoding");
         }