set refcount of string objects retrieved from zipmaps to 0, so we don't have...

set refcount of string objects retrieved from zipmaps to 0, so we don't have to touch the refcount of the objects inside dicts

redis.c

@@ -6066,8 +6066,10 @@ static void hashTryConversion(robj *subject, robj **argv, int start, int end) {
 }
 
 /* Get the value from a hash identified by key. Returns either a string
- * object or NULL if the value cannot be found. The refcount of the object
- * is always increased by 1 when the value was found. */
+ * object or NULL if the value cannot be found.
+ * Note: the refcount for objects retrieved from a zipmap is set to 0.
+ * This is done, so addReply will increment and clean up the object.
+ * Make sure to clean up the object when it isn't added to a reply. */
 static robj *hashGet(robj *o, robj *key) {
     robj *value = NULL;
     if (o->encoding == REDIS_ENCODING_ZIPMAP) {
@@ -6076,13 +6078,13 @@ static robj *hashGet(robj *o, robj *key) {
         key = getDecodedObject(key);
         if (zipmapGet(o->ptr,key->ptr,sdslen(key->ptr),&v,&vlen)) {
             value = createStringObject((char*)v,vlen);
+            value->refcount = 0;
         }
         decrRefCount(key);
     } else {
         dictEntry *de = dictFind(o->ptr,key);
         if (de != NULL) {
             value = dictGetEntryVal(de);
-            incrRefCount(value);
         }
     }
     return value;
@@ -6201,8 +6203,9 @@ static inline int hashNext(hashIterator *hi) {
     return REDIS_OK;
 }
 
-/* Get key or value object at current iteration position. This always
- * increases the refcount of the field object by 1. */
+/* Get key or value object at current iteration position.
+ * See comments at hashGet for a discussion on the refcount for
+ * keys and values retrieved from zipmaps. */
 static inline robj *hashCurrent(hashIterator *hi, int what) {
     robj *o;
     if (hi->encoding == REDIS_ENCODING_ZIPMAP) {
@@ -6211,13 +6214,13 @@ static inline robj *hashCurrent(hashIterator *hi, int what) {
         } else {
             o = createStringObject((char*)hi->zv,hi->zvlen);
         }
+        o->refcount = 0;
     } else {
         if (what & REDIS_HASH_KEY) {
             o = dictGetEntryKey(hi->de);
         } else {
             o = dictGetEntryVal(hi->de);
         }
-        incrRefCount(o);
     }
     return o;
 }
@@ -6293,7 +6296,12 @@ static void hincrbyCommand(redisClient *c) {
             value = (long)current->ptr;
         else
             redisAssert(1 != 1);
-        decrRefCount(current);
+
+        /* clean up object when it was retrieved from a zipmap */
+        if (current->refcount == 0) {
+            current->refcount = 1;
+            decrRefCount(current);
+        }
     } else {
         value = 0;
     }
@@ -6313,7 +6321,6 @@ static void hgetCommand(redisClient *c) {
 
     if ((value = hashGet(o,c->argv[2])) != NULL) {
         addReplyBulk(c,value);
-        decrRefCount(value);
     } else {
         addReply(c,shared.nullbulk);
     }
@@ -6334,7 +6341,6 @@ static void hmgetCommand(redisClient *c) {
     for (i = 2; i < c->argc; i++) {
         if (o != NULL && (value = hashGet(o,c->argv[i])) != NULL) {
             addReplyBulk(c,value);
-            decrRefCount(value);
         } else {
             addReply(c,shared.nullbulk);
         }
@@ -6380,13 +6386,11 @@ static void genericHgetallCommand(redisClient *c, int flags) {
         if (flags & REDIS_HASH_KEY) {
             obj = hashCurrent(&hi,REDIS_HASH_KEY);
             addReplyBulk(c,obj);
-            decrRefCount(obj);
             count++;
         }
         if (flags & REDIS_HASH_VALUE) {
             obj = hashCurrent(&hi,REDIS_HASH_VALUE);
             addReplyBulk(c,obj);
-            decrRefCount(obj);
             count++;
         }
     }