]> git.saurik.com Git - redis.git/blobdiff - redis.c
test-redis.tcl dataset digest function Hash support
[redis.git] / redis.c
diff --git a/redis.c b/redis.c
index cdc9c950b73adee361c0014282b2a5effb31be66..3f09763fbd179da1cdba2e84d2415de9f5c28e1c 100644 (file)
--- a/redis.c
+++ b/redis.c
@@ -27,7 +27,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-#define REDIS_VERSION "1.3.4"
+#define REDIS_VERSION "1.3.5"
 
 #include "fmacros.h"
 #include "config.h"
@@ -75,6 +75,7 @@
 #include "zmalloc.h" /* total memory usage aware version of malloc/free */
 #include "lzf.h"    /* LZF compression library */
 #include "pqsort.h" /* Partial qsort for SORT+LIMIT */
+#include "zipmap.h"
 
 /* Error codes */
 #define REDIS_OK                0
 #define REDIS_ZSET 3
 #define REDIS_HASH 4
 
-/* Objects encoding */
+/* Objects encoding. Some kind of objects like Strings and Hashes can be
+ * internally represented in multiple ways. The 'encoding' field of the object
+ * is set to one of this fields for this object. */
 #define REDIS_ENCODING_RAW 0    /* Raw representation */
 #define REDIS_ENCODING_INT 1    /* Encoded as integer */
+#define REDIS_ENCODING_ZIPMAP 2 /* Encoded as zipmap */
+#define REDIS_ENCODING_HT 3     /* Encoded as an hash table */
+
+static char* strencoding[] = {
+    "raw", "int", "zipmap", "hashtable"
+};
 
 /* Object types only used for dumping to disk */
 #define REDIS_EXPIRETIME 253
 #define APPENDFSYNC_ALWAYS 1
 #define APPENDFSYNC_EVERYSEC 2
 
+/* Hashes related defaults */
+#define REDIS_HASH_MAX_ZIPMAP_ENTRIES 64
+#define REDIS_HASH_MAX_ZIPMAP_VALUE 512
+
 /* We can print the stacktrace, so our assert is defined this way: */
 #define redisAssert(_e) ((_e)?(void)0 : (_redisAssert(#_e,__FILE__,__LINE__),_exit(1)))
 static void _redisAssert(char *estr, char *file, int line);
@@ -386,6 +399,9 @@ struct redisServer {
     off_t vm_page_size;
     off_t vm_pages;
     unsigned long long vm_max_memory;
+    /* Hashes config */
+    size_t hash_max_zipmap_entries;
+    size_t hash_max_zipmap_value;
     /* Virtual memory state */
     FILE *vm_fp;
     int vm_fd;
@@ -427,6 +443,10 @@ struct redisCommand {
     redisCommandProc *proc;
     int arity;
     int flags;
+    /* Use a function to determine which keys need to be loaded
+     * in the background prior to executing this command. Takes precedence
+     * over vm_firstkey and others, ignored when NULL */
+    redisCommandProc *vm_preload_proc;
     /* What keys should be loaded in background when calling this command? */
     int vm_firstkey; /* The first argument that's a key (0 = no keys) */
     int vm_lastkey;  /* THe last argument that's a key */
@@ -571,6 +591,7 @@ static robj *vmReadObjectFromSwap(off_t page, int type);
 static void waitEmptyIOJobsQueue(void);
 static void vmReopenSwapFile(void);
 static int vmFreePage(off_t page);
+static void zunionInterBlockClientOnSwappedKeys(redisClient *c);
 static int blockClientOnSwappedKeys(struct redisCommand *cmd, redisClient *c);
 static int dontWaitForSwappedKey(redisClient *c, robj *key);
 static void handleClientsBlockedOnSwappedKey(redisDb *db, robj *key);
@@ -578,6 +599,7 @@ static void readQueryFromClient(aeEventLoop *el, int fd, void *privdata, int mas
 static struct redisCommand *lookupCommand(char *name);
 static void call(redisClient *c, struct redisCommand *cmd);
 static void resetClient(redisClient *c);
+static void convertToRealHash(robj *o);
 
 static void authCommand(redisClient *c);
 static void pingCommand(redisClient *c);
@@ -661,96 +683,120 @@ static void brpopCommand(redisClient *c);
 static void appendCommand(redisClient *c);
 static void substrCommand(redisClient *c);
 static void zrankCommand(redisClient *c);
+static void zrevrankCommand(redisClient *c);
+static void hsetCommand(redisClient *c);
+static void hgetCommand(redisClient *c);
+static void hdelCommand(redisClient *c);
+static void hlenCommand(redisClient *c);
+static void zremrangebyrankCommand(redisClient *c);
+static void zunionCommand(redisClient *c);
+static void zinterCommand(redisClient *c);
+static void hkeysCommand(redisClient *c);
+static void hvalsCommand(redisClient *c);
+static void hgetallCommand(redisClient *c);
+static void hexistsCommand(redisClient *c);
 
 /*================================= Globals ================================= */
 
 /* Global vars */
 static struct redisServer server; /* server global state */
 static struct redisCommand cmdTable[] = {
-    {"get",getCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"set",setCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,0,0,0},
-    {"setnx",setnxCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,0,0,0},
-    {"append",appendCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
-    {"substr",substrCommand,4,REDIS_CMD_INLINE,1,1,1},
-    {"del",delCommand,-2,REDIS_CMD_INLINE,0,0,0},
-    {"exists",existsCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"incr",incrCommand,2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,1,1},
-    {"decr",decrCommand,2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,1,1},
-    {"mget",mgetCommand,-2,REDIS_CMD_INLINE,1,-1,1},
-    {"rpush",rpushCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
-    {"lpush",lpushCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
-    {"rpop",rpopCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"lpop",lpopCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"brpop",brpopCommand,-3,REDIS_CMD_INLINE,1,1,1},
-    {"blpop",blpopCommand,-3,REDIS_CMD_INLINE,1,1,1},
-    {"llen",llenCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"lindex",lindexCommand,3,REDIS_CMD_INLINE,1,1,1},
-    {"lset",lsetCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
-    {"lrange",lrangeCommand,4,REDIS_CMD_INLINE,1,1,1},
-    {"ltrim",ltrimCommand,4,REDIS_CMD_INLINE,1,1,1},
-    {"lrem",lremCommand,4,REDIS_CMD_BULK,1,1,1},
-    {"rpoplpush",rpoplpushcommand,3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,2,1},
-    {"sadd",saddCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
-    {"srem",sremCommand,3,REDIS_CMD_BULK,1,1,1},
-    {"smove",smoveCommand,4,REDIS_CMD_BULK,1,2,1},
-    {"sismember",sismemberCommand,3,REDIS_CMD_BULK,1,1,1},
-    {"scard",scardCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"spop",spopCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"srandmember",srandmemberCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"sinter",sinterCommand,-2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,-1,1},
-    {"sinterstore",sinterstoreCommand,-3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,2,-1,1},
-    {"sunion",sunionCommand,-2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,-1,1},
-    {"sunionstore",sunionstoreCommand,-3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,2,-1,1},
-    {"sdiff",sdiffCommand,-2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,-1,1},
-    {"sdiffstore",sdiffstoreCommand,-3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,2,-1,1},
-    {"smembers",sinterCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"zadd",zaddCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
-    {"zincrby",zincrbyCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
-    {"zrem",zremCommand,3,REDIS_CMD_BULK,1,1,1},
-    {"zremrangebyscore",zremrangebyscoreCommand,4,REDIS_CMD_INLINE,1,1,1},
-    {"zrange",zrangeCommand,-4,REDIS_CMD_INLINE,1,1,1},
-    {"zrangebyscore",zrangebyscoreCommand,-4,REDIS_CMD_INLINE,1,1,1},
-    {"zcount",zcountCommand,4,REDIS_CMD_INLINE,1,1,1},
-    {"zrevrange",zrevrangeCommand,-4,REDIS_CMD_INLINE,1,1,1},
-    {"zcard",zcardCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"zscore",zscoreCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
-    {"zrank",zrankCommand,3,REDIS_CMD_INLINE,1,1,1},
-    {"incrby",incrbyCommand,3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,1,1},
-    {"decrby",decrbyCommand,3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,1,1},
-    {"getset",getsetCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
-    {"mset",msetCommand,-3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,-1,2},
-    {"msetnx",msetnxCommand,-3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,-1,2},
-    {"randomkey",randomkeyCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"select",selectCommand,2,REDIS_CMD_INLINE,0,0,0},
-    {"move",moveCommand,3,REDIS_CMD_INLINE,1,1,1},
-    {"rename",renameCommand,3,REDIS_CMD_INLINE,1,1,1},
-    {"renamenx",renamenxCommand,3,REDIS_CMD_INLINE,1,1,1},
-    {"expire",expireCommand,3,REDIS_CMD_INLINE,0,0,0},
-    {"expireat",expireatCommand,3,REDIS_CMD_INLINE,0,0,0},
-    {"keys",keysCommand,2,REDIS_CMD_INLINE,0,0,0},
-    {"dbsize",dbsizeCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"auth",authCommand,2,REDIS_CMD_INLINE,0,0,0},
-    {"ping",pingCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"echo",echoCommand,2,REDIS_CMD_BULK,0,0,0},
-    {"save",saveCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"bgsave",bgsaveCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"bgrewriteaof",bgrewriteaofCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"shutdown",shutdownCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"lastsave",lastsaveCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"type",typeCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"multi",multiCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"exec",execCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"discard",discardCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"sync",syncCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"flushdb",flushdbCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"flushall",flushallCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"sort",sortCommand,-2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,1,1},
-    {"info",infoCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"monitor",monitorCommand,1,REDIS_CMD_INLINE,0,0,0},
-    {"ttl",ttlCommand,2,REDIS_CMD_INLINE,1,1,1},
-    {"slaveof",slaveofCommand,3,REDIS_CMD_INLINE,0,0,0},
-    {"debug",debugCommand,-2,REDIS_CMD_INLINE,0,0,0},
-    {NULL,NULL,0,0,0,0,0}
+    {"get",getCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"set",setCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,0,0,0},
+    {"setnx",setnxCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,0,0,0},
+    {"append",appendCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"substr",substrCommand,4,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"del",delCommand,-2,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"exists",existsCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"incr",incrCommand,2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"decr",decrCommand,2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"mget",mgetCommand,-2,REDIS_CMD_INLINE,NULL,1,-1,1},
+    {"rpush",rpushCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"lpush",lpushCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"rpop",rpopCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"lpop",lpopCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"brpop",brpopCommand,-3,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"blpop",blpopCommand,-3,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"llen",llenCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"lindex",lindexCommand,3,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"lset",lsetCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"lrange",lrangeCommand,4,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"ltrim",ltrimCommand,4,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"lrem",lremCommand,4,REDIS_CMD_BULK,NULL,1,1,1},
+    {"rpoplpush",rpoplpushcommand,3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,2,1},
+    {"sadd",saddCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"srem",sremCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
+    {"smove",smoveCommand,4,REDIS_CMD_BULK,NULL,1,2,1},
+    {"sismember",sismemberCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
+    {"scard",scardCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"spop",spopCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"srandmember",srandmemberCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"sinter",sinterCommand,-2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,-1,1},
+    {"sinterstore",sinterstoreCommand,-3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,2,-1,1},
+    {"sunion",sunionCommand,-2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,-1,1},
+    {"sunionstore",sunionstoreCommand,-3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,2,-1,1},
+    {"sdiff",sdiffCommand,-2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,-1,1},
+    {"sdiffstore",sdiffstoreCommand,-3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,2,-1,1},
+    {"smembers",sinterCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"zadd",zaddCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"zincrby",zincrbyCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"zrem",zremCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
+    {"zremrangebyscore",zremrangebyscoreCommand,4,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"zremrangebyrank",zremrangebyrankCommand,4,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"zunion",zunionCommand,-4,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,zunionInterBlockClientOnSwappedKeys,0,0,0},
+    {"zinter",zinterCommand,-4,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,zunionInterBlockClientOnSwappedKeys,0,0,0},
+    {"zrange",zrangeCommand,-4,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"zrangebyscore",zrangebyscoreCommand,-4,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"zcount",zcountCommand,4,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"zrevrange",zrevrangeCommand,-4,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"zcard",zcardCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"zscore",zscoreCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"zrank",zrankCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
+    {"zrevrank",zrevrankCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
+    {"hset",hsetCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"hget",hgetCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
+    {"hdel",hdelCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
+    {"hlen",hlenCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"hkeys",hkeysCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"hvals",hvalsCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"hgetall",hgetallCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"hexists",hexistsCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
+    {"incrby",incrbyCommand,3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"decrby",decrbyCommand,3,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"getset",getsetCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"mset",msetCommand,-3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,-1,2},
+    {"msetnx",msetnxCommand,-3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,-1,2},
+    {"randomkey",randomkeyCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"select",selectCommand,2,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"move",moveCommand,3,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"rename",renameCommand,3,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"renamenx",renamenxCommand,3,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"expire",expireCommand,3,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"expireat",expireatCommand,3,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"keys",keysCommand,2,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"dbsize",dbsizeCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"auth",authCommand,2,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"ping",pingCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"echo",echoCommand,2,REDIS_CMD_BULK,NULL,0,0,0},
+    {"save",saveCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"bgsave",bgsaveCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"bgrewriteaof",bgrewriteaofCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"shutdown",shutdownCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"lastsave",lastsaveCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"type",typeCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"multi",multiCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"exec",execCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"discard",discardCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"sync",syncCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"flushdb",flushdbCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"flushall",flushallCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"sort",sortCommand,-2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"info",infoCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"monitor",monitorCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"ttl",ttlCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
+    {"slaveof",slaveofCommand,3,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"debug",debugCommand,-2,REDIS_CMD_INLINE,NULL,0,0,0},
+    {NULL,NULL,0,0,NULL,0,0,0}
 };
 
 /*============================ Utility functions ============================ */
@@ -959,6 +1005,10 @@ static int dictEncObjKeyCompare(void *privdata, const void *key1,
     robj *o1 = (robj*) key1, *o2 = (robj*) key2;
     int cmp;
 
+    if (o1->encoding == REDIS_ENCODING_INT &&
+        o2->encoding == REDIS_ENCODING_INT &&
+        o1->ptr == o2->ptr) return 1;
+
     o1 = getDecodedObject(o1);
     o2 = getDecodedObject(o2);
     cmp = sdsDictKeyCompare(privdata,o1->ptr,o2->ptr);
@@ -1011,7 +1061,7 @@ static dictType zsetDictType = {
 };
 
 /* Db->dict */
-static dictType hashDictType = {
+static dictType dbDictType = {
     dictObjHash,                /* hash function */
     NULL,                       /* key dup */
     NULL,                       /* val dup */
@@ -1030,6 +1080,16 @@ static dictType keyptrDictType = {
     NULL                       /* val destructor */
 };
 
+/* Hash type hash table (note that small hashes are represented with zimpaps) */
+static dictType hashDictType = {
+    dictEncObjHash,             /* hash function */
+    NULL,                       /* key dup */
+    NULL,                       /* val dup */
+    dictEncObjKeyCompare,       /* key compare */
+    dictRedisObjectDestructor,  /* key destructor */
+    dictRedisObjectDestructor   /* val destructor */
+};
+
 /* Keylist hash table type has unencoded redis objects as keys and
  * lists as values. It's used for blocking operations (BLPOP) and to
  * map swapped keys to a list of clients waiting for this keys to be loaded. */
@@ -1446,6 +1506,8 @@ static void initServerConfig() {
     server.vm_max_memory = 1024LL*1024*1024*1; /* 1 GB of RAM */
     server.vm_max_threads = 4;
     server.vm_blocked_clients = 0;
+    server.hash_max_zipmap_entries = REDIS_HASH_MAX_ZIPMAP_ENTRIES;
+    server.hash_max_zipmap_value = REDIS_HASH_MAX_ZIPMAP_VALUE;
 
     resetServerSaveParams();
 
@@ -1493,7 +1555,7 @@ static void initServer() {
         exit(1);
     }
     for (j = 0; j < server.dbnum; j++) {
-        server.db[j].dict = dictCreate(&hashDictType,NULL);
+        server.db[j].dict = dictCreate(&dbDictType,NULL);
         server.db[j].expires = dictCreate(&keyptrDictType,NULL);
         server.db[j].blockingkeys = dictCreate(&keylistDictType,NULL);
         if (server.vm_enabled)
@@ -1706,6 +1768,12 @@ static void loadServerConfig(char *filename) {
             server.vm_pages = strtoll(argv[1], NULL, 10);
         } else if (!strcasecmp(argv[0],"vm-max-threads") && argc == 2) {
             server.vm_max_threads = strtoll(argv[1], NULL, 10);
+        } else if (!strcasecmp(argv[0],"hash-max-zipmap-entries") && argc == 2){
+            server.hash_max_zipmap_entries = strtol(argv[1], NULL, 10);
+        } else if (!strcasecmp(argv[0],"hash-max-zipmap-value") && argc == 2){
+            server.hash_max_zipmap_value = strtol(argv[1], NULL, 10);
+        } else if (!strcasecmp(argv[0],"vm-max-threads") && argc == 2) {
+            server.vm_max_threads = strtoll(argv[1], NULL, 10);
         } else {
             err = "Bad directive or wrong number of arguments"; goto loaderr;
         }
@@ -2427,10 +2495,32 @@ static void addReplyLong(redisClient *c, long l) {
     char buf[128];
     size_t len;
 
+    if (l == 0) {
+        addReply(c,shared.czero);
+        return;
+    } else if (l == 1) {
+        addReply(c,shared.cone);
+        return;
+    }
     len = snprintf(buf,sizeof(buf),":%ld\r\n",l);
     addReplySds(c,sdsnewlen(buf,len));
 }
 
+static void addReplyUlong(redisClient *c, unsigned long ul) {
+    char buf[128];
+    size_t len;
+
+    if (ul == 0) {
+        addReply(c,shared.czero);
+        return;
+    } else if (ul == 1) {
+        addReply(c,shared.cone);
+        return;
+    }
+    len = snprintf(buf,sizeof(buf),":%lu\r\n",ul);
+    addReplySds(c,sdsnewlen(buf,len));
+}
+
 static void addReplyBulkLen(redisClient *c, robj *obj) {
     size_t len;
 
@@ -2452,6 +2542,12 @@ static void addReplyBulkLen(redisClient *c, robj *obj) {
     addReplySds(c,sdscatprintf(sdsempty(),"$%lu\r\n",(unsigned long)len));
 }
 
+static void addReplyBulk(redisClient *c, robj *obj) {
+    addReplyBulkLen(c,obj);
+    addReply(c,obj);
+    addReply(c,shared.crlf);
+}
+
 static void acceptHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
     int cport, cfd;
     char cip[128];
@@ -2543,6 +2639,16 @@ static robj *createSetObject(void) {
     return createObject(REDIS_SET,d);
 }
 
+static robj *createHashObject(void) {
+    /* All the Hashes start as zipmaps. Will be automatically converted
+     * into hash tables if there are enough elements or big elements
+     * inside. */
+    unsigned char *zm = zipmapNew();
+    robj *o = createObject(REDIS_HASH,zm);
+    o->encoding = REDIS_ENCODING_ZIPMAP;
+    return o;
+}
+
 static robj *createZsetObject(void) {
     zset *zs = zmalloc(sizeof(*zs));
 
@@ -2574,7 +2680,17 @@ static void freeZsetObject(robj *o) {
 }
 
 static void freeHashObject(robj *o) {
-    dictRelease((dict*) o->ptr);
+    switch (o->encoding) {
+    case REDIS_ENCODING_HT:
+        dictRelease((dict*) o->ptr);
+        break;
+    case REDIS_ENCODING_ZIPMAP:
+        zfree(o->ptr);
+        break;
+    default:
+        redisAssert(0);
+        break;
+    }
 }
 
 static void incrRefCount(robj *o) {
@@ -2615,7 +2731,7 @@ static void decrRefCount(void *obj) {
         case REDIS_SET: freeSetObject(o); break;
         case REDIS_ZSET: freeZsetObject(o); break;
         case REDIS_HASH: freeHashObject(o); break;
-        default: redisAssert(0 != 0); break;
+        default: redisAssert(0); break;
         }
         if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
         if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX ||
@@ -2670,6 +2786,26 @@ static robj *lookupKeyWrite(redisDb *db, robj *key) {
     return lookupKey(db,key);
 }
 
+static robj *lookupKeyReadOrReply(redisClient *c, robj *key, robj *reply) {
+    robj *o = lookupKeyRead(c->db, key);
+    if (!o) addReply(c,reply);
+    return o;
+}
+
+static robj *lookupKeyWriteOrReply(redisClient *c, robj *key, robj *reply) {
+    robj *o = lookupKeyWrite(c->db, key);
+    if (!o) addReply(c,reply);
+    return o;
+}
+
+static int checkType(redisClient *c, robj *o, int type) {
+    if (o->type != type) {
+        addReply(c,shared.wrongtypeerr);
+        return 1;
+    }
+    return 0;
+}
+
 static int deleteKey(redisDb *db, robj *key) {
     int retval;
 
@@ -2879,7 +3015,7 @@ static int rdbSaveLen(FILE *fp, uint32_t len) {
 /* String objects in the form "2391" "-100" without any space and with a
  * range of values that can fit in an 8, 16 or 32 bit signed value can be
  * encoded as integers to save space */
-static int rdbTryIntegerEncoding(sds s, unsigned char *enc) {
+static int rdbTryIntegerEncoding(char *s, size_t len, unsigned char *enc) {
     long long value;
     char *endptr, buf[32];
 
@@ -2890,7 +3026,7 @@ static int rdbTryIntegerEncoding(sds s, unsigned char *enc) {
 
     /* If the number converted back into a string is not identical
      * then it's not possible to encode the string as integer */
-    if (strlen(buf) != sdslen(s) || memcmp(buf,s,sdslen(s))) return 0;
+    if (strlen(buf) != len || memcmp(buf,s,len)) return 0;
 
     /* Finally check if it fits in our ranges */
     if (value >= -(1<<7) && value <= (1<<7)-1) {
@@ -2914,16 +3050,16 @@ static int rdbTryIntegerEncoding(sds s, unsigned char *enc) {
     }
 }
 
-static int rdbSaveLzfStringObject(FILE *fp, robj *obj) {
-    unsigned int comprlen, outlen;
+static int rdbSaveLzfStringObject(FILE *fp, unsigned char *s, size_t len) {
+    size_t comprlen, outlen;
     unsigned char byte;
     void *out;
 
     /* We require at least four bytes compression for this to be worth it */
-    outlen = sdslen(obj->ptr)-4;
-    if (outlen <= 0) return 0;
+    if (len <= 4) return 0;
+    outlen = len-4;
     if ((out = zmalloc(outlen+1)) == NULL) return 0;
-    comprlen = lzf_compress(obj->ptr, sdslen(obj->ptr), out, outlen);
+    comprlen = lzf_compress(s, len, out, outlen);
     if (comprlen == 0) {
         zfree(out);
         return 0;
@@ -2932,7 +3068,7 @@ static int rdbSaveLzfStringObject(FILE *fp, robj *obj) {
     byte = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_LZF;
     if (fwrite(&byte,1,1,fp) == 0) goto writeerr;
     if (rdbSaveLen(fp,comprlen) == -1) goto writeerr;
-    if (rdbSaveLen(fp,sdslen(obj->ptr)) == -1) goto writeerr;
+    if (rdbSaveLen(fp,len) == -1) goto writeerr;
     if (fwrite(out,comprlen,1,fp) == 0) goto writeerr;
     zfree(out);
     return comprlen;
@@ -2944,16 +3080,13 @@ writeerr:
 
 /* Save a string objet as [len][data] on disk. If the object is a string
  * representation of an integer value we try to safe it in a special form */
-static int rdbSaveStringObjectRaw(FILE *fp, robj *obj) {
-    size_t len;
+static int rdbSaveRawString(FILE *fp, unsigned char *s, size_t len) {
     int enclen;
 
-    len = sdslen(obj->ptr);
-
     /* Try integer encoding */
     if (len <= 11) {
         unsigned char buf[5];
-        if ((enclen = rdbTryIntegerEncoding(obj->ptr,buf)) > 0) {
+        if ((enclen = rdbTryIntegerEncoding((char*)s,len,buf)) > 0) {
             if (fwrite(buf,enclen,1,fp) == 0) return -1;
             return 0;
         }
@@ -2964,7 +3097,7 @@ static int rdbSaveStringObjectRaw(FILE *fp, robj *obj) {
     if (server.rdbcompression && len > 20) {
         int retval;
 
-        retval = rdbSaveLzfStringObject(fp,obj);
+        retval = rdbSaveLzfStringObject(fp,s,len);
         if (retval == -1) return -1;
         if (retval > 0) return 0;
         /* retval == 0 means data can't be compressed, save the old way */
@@ -2972,7 +3105,7 @@ static int rdbSaveStringObjectRaw(FILE *fp, robj *obj) {
 
     /* Store verbatim */
     if (rdbSaveLen(fp,len) == -1) return -1;
-    if (len && fwrite(obj->ptr,len,1,fp) == 0) return -1;
+    if (len && fwrite(s,len,1,fp) == 0) return -1;
     return 0;
 }
 
@@ -2987,10 +3120,10 @@ static int rdbSaveStringObject(FILE *fp, robj *obj) {
      * this in order to avoid bugs) */
     if (obj->encoding != REDIS_ENCODING_RAW) {
         obj = getDecodedObject(obj);
-        retval = rdbSaveStringObjectRaw(fp,obj);
+        retval = rdbSaveRawString(fp,obj->ptr,sdslen(obj->ptr));
         decrRefCount(obj);
     } else {
-        retval = rdbSaveStringObjectRaw(fp,obj);
+        retval = rdbSaveRawString(fp,obj->ptr,sdslen(obj->ptr));
     }
     return retval;
 }
@@ -3068,8 +3201,35 @@ static int rdbSaveObject(FILE *fp, robj *o) {
             if (rdbSaveDoubleValue(fp,*score) == -1) return -1;
         }
         dictReleaseIterator(di);
+    } else if (o->type == REDIS_HASH) {
+        /* Save a hash value */
+        if (o->encoding == REDIS_ENCODING_ZIPMAP) {
+            unsigned char *p = zipmapRewind(o->ptr);
+            unsigned int count = zipmapLen(o->ptr);
+            unsigned char *key, *val;
+            unsigned int klen, vlen;
+
+            if (rdbSaveLen(fp,count) == -1) return -1;
+            while((p = zipmapNext(p,&key,&klen,&val,&vlen)) != NULL) {
+                if (rdbSaveRawString(fp,key,klen) == -1) return -1;
+                if (rdbSaveRawString(fp,val,vlen) == -1) return -1;
+            }
+        } else {
+            dictIterator *di = dictGetIterator(o->ptr);
+            dictEntry *de;
+
+            if (rdbSaveLen(fp,dictSize((dict*)o->ptr)) == -1) return -1;
+            while((de = dictNext(di)) != NULL) {
+                robj *key = dictGetEntryKey(de);
+                robj *val = dictGetEntryVal(de);
+
+                if (rdbSaveStringObject(fp,key) == -1) return -1;
+                if (rdbSaveStringObject(fp,val) == -1) return -1;
+            }
+            dictReleaseIterator(di);
+        }
     } else {
-        redisAssert(0 != 0);
+        redisAssert(0);
     }
     return 0;
 }
@@ -3289,7 +3449,7 @@ static robj *rdbLoadIntegerObject(FILE *fp, int enctype) {
         val = (int32_t)v;
     } else {
         val = 0; /* anti-warning */
-        redisAssert(0!=0);
+        redisAssert(0);
     }
     return createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",val));
 }
@@ -3328,7 +3488,7 @@ static robj *rdbLoadStringObject(FILE*fp) {
         case REDIS_RDB_ENC_LZF:
             return tryObjectSharing(rdbLoadLzfStringObject(fp));
         default:
-            redisAssert(0!=0);
+            redisAssert(0);
         }
     }
 
@@ -3364,6 +3524,7 @@ static int rdbLoadDoubleValue(FILE *fp, double *val) {
 static robj *rdbLoadObject(int type, FILE *fp) {
     robj *o;
 
+    redisLog(REDIS_DEBUG,"LOADING OBJECT %d (at %d)\n",type,ftell(fp));
     if (type == REDIS_STRING) {
         /* Read string value */
         if ((o = rdbLoadStringObject(fp)) == NULL) return NULL;
@@ -3392,7 +3553,7 @@ static robj *rdbLoadObject(int type, FILE *fp) {
         }
     } else if (type == REDIS_ZSET) {
         /* Read list/set value */
-        uint32_t zsetlen;
+        size_t zsetlen;
         zset *zs;
 
         if ((zsetlen = rdbLoadLen(fp,NULL)) == REDIS_RDB_LENERR) return NULL;
@@ -3410,8 +3571,46 @@ static robj *rdbLoadObject(int type, FILE *fp) {
             zslInsert(zs->zsl,*score,ele);
             incrRefCount(ele); /* added to skiplist */
         }
+    } else if (type == REDIS_HASH) {
+        size_t hashlen;
+
+        if ((hashlen = rdbLoadLen(fp,NULL)) == REDIS_RDB_LENERR) return NULL;
+        o = createHashObject();
+        /* Too many entries? Use an hash table. */
+        if (hashlen > server.hash_max_zipmap_entries)
+            convertToRealHash(o);
+        /* Load every key/value, then set it into the zipmap or hash
+         * table, as needed. */
+        while(hashlen--) {
+            robj *key, *val;
+
+            if ((key = rdbLoadStringObject(fp)) == NULL) return NULL;
+            if ((val = rdbLoadStringObject(fp)) == NULL) return NULL;
+            /* If we are using a zipmap and there are too big values
+             * the object is converted to real hash table encoding. */
+            if (o->encoding != REDIS_ENCODING_HT &&
+               (sdslen(key->ptr) > server.hash_max_zipmap_value ||
+                sdslen(val->ptr) > server.hash_max_zipmap_value))
+            {
+                    convertToRealHash(o);
+            }
+
+            if (o->encoding == REDIS_ENCODING_ZIPMAP) {
+                unsigned char *zm = o->ptr;
+
+                zm = zipmapSet(zm,key->ptr,sdslen(key->ptr),
+                                  val->ptr,sdslen(val->ptr),NULL);
+                o->ptr = zm;
+                decrRefCount(key);
+                decrRefCount(val);
+            } else {
+                tryObjectEncoding(key);
+                tryObjectEncoding(val);
+                dictAdd((dict*)o->ptr,key,val);
+            }
+        }
     } else {
-        redisAssert(0 != 0);
+        redisAssert(0);
     }
     return o;
 }
@@ -3518,9 +3717,7 @@ static void pingCommand(redisClient *c) {
 }
 
 static void echoCommand(redisClient *c) {
-    addReplyBulkLen(c,c->argv[1]);
-    addReply(c,c->argv[1]);
-    addReply(c,shared.crlf);
+    addReplyBulk(c,c->argv[1]);
 }
 
 /*=================================== Strings =============================== */
@@ -3536,7 +3733,7 @@ static void setGenericCommand(redisClient *c, int nx) {
              * to overwrite the old. So we delete the old key in the database.
              * This will also make sure that swap pages about the old object
              * will be marked as free. */
-            if (deleteIfSwapped(c->db,c->argv[1]))
+            if (server.vm_enabled && deleteIfSwapped(c->db,c->argv[1]))
                 incrRefCount(c->argv[1]);
             dictReplace(c->db->dict,c->argv[1],c->argv[2]);
             incrRefCount(c->argv[2]);
@@ -3562,21 +3759,17 @@ static void setnxCommand(redisClient *c) {
 }
 
 static int getGenericCommand(redisClient *c) {
-    robj *o = lookupKeyRead(c->db,c->argv[1]);
-
-    if (o == NULL) {
-        addReply(c,shared.nullbulk);
+    robj *o;
+    
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL)
         return REDIS_OK;
+
+    if (o->type != REDIS_STRING) {
+        addReply(c,shared.wrongtypeerr);
+        return REDIS_ERR;
     } else {
-        if (o->type != REDIS_STRING) {
-            addReply(c,shared.wrongtypeerr);
-            return REDIS_ERR;
-        } else {
-            addReplyBulkLen(c,o);
-            addReply(c,o);
-            addReply(c,shared.crlf);
-            return REDIS_OK;
-        }
+        addReplyBulk(c,o);
+        return REDIS_OK;
     }
 }
 
@@ -3608,9 +3801,7 @@ static void mgetCommand(redisClient *c) {
             if (o->type != REDIS_STRING) {
                 addReply(c,shared.nullbulk);
             } else {
-                addReplyBulkLen(c,o);
-                addReply(c,o);
-                addReply(c,shared.crlf);
+                addReplyBulk(c,o);
             }
         }
     }
@@ -3770,44 +3961,37 @@ static void substrCommand(redisClient *c) {
     robj *o;
     long start = atoi(c->argv[2]->ptr);
     long end = atoi(c->argv[3]->ptr);
+    size_t rangelen, strlen;
+    sds range;
 
-    o = lookupKeyRead(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.nullbulk);
-    } else {
-        if (o->type != REDIS_STRING) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            size_t rangelen, strlen;
-            sds range;
-
-            o = getDecodedObject(o);
-            strlen = sdslen(o->ptr);
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
+        checkType(c,o,REDIS_STRING)) return;
 
-            /* convert negative indexes */
-            if (start < 0) start = strlen+start;
-            if (end < 0) end = strlen+end;
-            if (start < 0) start = 0;
-            if (end < 0) end = 0;
+    o = getDecodedObject(o);
+    strlen = sdslen(o->ptr);
 
-            /* indexes sanity checks */
-            if (start > end || (size_t)start >= strlen) {
-                /* Out of range start or start > end result in null reply */
-                addReply(c,shared.nullbulk);
-                decrRefCount(o);
-                return;
-            }
-            if ((size_t)end >= strlen) end = strlen-1;
-            rangelen = (end-start)+1;
+    /* convert negative indexes */
+    if (start < 0) start = strlen+start;
+    if (end < 0) end = strlen+end;
+    if (start < 0) start = 0;
+    if (end < 0) end = 0;
 
-            /* Return the result */
-            addReplySds(c,sdscatprintf(sdsempty(),"$%lu\r\n",rangelen));
-            range = sdsnewlen((char*)o->ptr+start,rangelen);
-            addReplySds(c,range);
-            addReply(c,shared.crlf);
-            decrRefCount(o);
-        }
+    /* indexes sanity checks */
+    if (start > end || (size_t)start >= strlen) {
+        /* Out of range start or start > end result in null reply */
+        addReply(c,shared.nullbulk);
+        decrRefCount(o);
+        return;
     }
+    if ((size_t)end >= strlen) end = strlen-1;
+    rangelen = (end-start)+1;
+
+    /* Return the result */
+    addReplySds(c,sdscatprintf(sdsempty(),"$%zu\r\n",rangelen));
+    range = sdsnewlen((char*)o->ptr+start,rangelen);
+    addReplySds(c,range);
+    addReply(c,shared.crlf);
+    decrRefCount(o);
 }
 
 /* ========================= Type agnostic commands ========================= */
@@ -3821,17 +4005,7 @@ static void delCommand(redisClient *c) {
             deleted++;
         }
     }
-    switch(deleted) {
-    case 0:
-        addReply(c,shared.czero);
-        break;
-    case 1:
-        addReply(c,shared.cone);
-        break;
-    default:
-        addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",deleted));
-        break;
-    }
+    addReplyLong(c,deleted);
 }
 
 static void existsCommand(redisClient *c) {
@@ -3883,9 +4057,7 @@ static void keysCommand(redisClient *c) {
         if ((pattern[0] == '*' && pattern[1] == '\0') ||
             stringmatchlen(pattern,plen,key,sdslen(key),0)) {
             if (expireIfNeeded(c->db,keyobj) == 0) {
-                addReplyBulkLen(c,keyobj);
-                addReply(c,keyobj);
-                addReply(c,shared.crlf);
+                addReplyBulk(c,keyobj);
                 numkeys++;
             }
         }
@@ -3917,7 +4089,8 @@ static void typeCommand(redisClient *c) {
         case REDIS_LIST: type = "+list"; break;
         case REDIS_SET: type = "+set"; break;
         case REDIS_ZSET: type = "+zset"; break;
-        default: type = "unknown"; break;
+        case REDIS_HASH: type = "+hash"; break;
+        default: type = "+unknown"; break;
         }
     }
     addReplySds(c,sdsnew(type));
@@ -3974,12 +4147,14 @@ static void shutdownCommand(redisClient *c) {
             if (server.vm_enabled) unlink(server.vm_swap_file);
             exit(0);
         } else {
-            /* Ooops.. error saving! The best we can do is to continue operating.
-             * Note that if there was a background saving process, in the next
-             * cron() Redis will be notified that the background saving aborted,
-             * handling special stuff like slaves pending for synchronization... */
+            /* Ooops.. error saving! The best we can do is to continue
+             * operating. Note that if there was a background saving process,
+             * in the next cron() Redis will be notified that the background
+             * saving aborted, handling special stuff like slaves pending for
+             * synchronization... */
             redisLog(REDIS_WARNING,"Error trying to save the DB, can't exit"); 
-            addReplySds(c,sdsnew("-ERR can't quit, problems saving the DB\r\n"));
+            addReplySds(c,
+                sdsnew("-ERR can't quit, problems saving the DB\r\n"));
         }
     }
 }
@@ -3993,11 +4168,9 @@ static void renameGenericCommand(redisClient *c, int nx) {
         return;
     }
 
-    o = lookupKeyWrite(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.nokeyerr);
+    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr)) == NULL)
         return;
-    }
+
     incrRefCount(o);
     deleteIfVolatile(c->db,c->argv[2]);
     if (dictAdd(c->db->dict,c->argv[2],o) == DICT_ERR) {
@@ -4075,7 +4248,7 @@ static void pushGenericCommand(redisClient *c, int where) {
     lobj = lookupKeyWrite(c->db,c->argv[1]);
     if (lobj == NULL) {
         if (handleClientsWaitingListPush(c,c->argv[1],c->argv[2])) {
-            addReply(c,shared.ok);
+            addReply(c,shared.cone);
             return;
         }
         lobj = createListObject();
@@ -4094,7 +4267,7 @@ static void pushGenericCommand(redisClient *c, int where) {
             return;
         }
         if (handleClientsWaitingListPush(c,c->argv[1],c->argv[2])) {
-            addReply(c,shared.ok);
+            addReply(c,shared.cone);
             return;
         }
         list = lobj->ptr;
@@ -4106,7 +4279,7 @@ static void pushGenericCommand(redisClient *c, int where) {
         incrRefCount(c->argv[2]);
     }
     server.dirty++;
-    addReply(c,shared.ok);
+    addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",listLength(list)));
 }
 
 static void lpushCommand(redisClient *c) {
@@ -4120,107 +4293,78 @@ static void rpushCommand(redisClient *c) {
 static void llenCommand(redisClient *c) {
     robj *o;
     list *l;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,REDIS_LIST)) return;
     
-    o = lookupKeyRead(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.czero);
-        return;
-    } else {
-        if (o->type != REDIS_LIST) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            l = o->ptr;
-            addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",listLength(l)));
-        }
-    }
+    l = o->ptr;
+    addReplyUlong(c,listLength(l));
 }
 
 static void lindexCommand(redisClient *c) {
     robj *o;
     int index = atoi(c->argv[2]->ptr);
-    
-    o = lookupKeyRead(c->db,c->argv[1]);
-    if (o == NULL) {
+    list *list;
+    listNode *ln;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
+        checkType(c,o,REDIS_LIST)) return;
+    list = o->ptr;
+
+    ln = listIndex(list, index);
+    if (ln == NULL) {
         addReply(c,shared.nullbulk);
     } else {
-        if (o->type != REDIS_LIST) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            list *list = o->ptr;
-            listNode *ln;
-            
-            ln = listIndex(list, index);
-            if (ln == NULL) {
-                addReply(c,shared.nullbulk);
-            } else {
-                robj *ele = listNodeValue(ln);
-                addReplyBulkLen(c,ele);
-                addReply(c,ele);
-                addReply(c,shared.crlf);
-            }
-        }
+        robj *ele = listNodeValue(ln);
+        addReplyBulk(c,ele);
     }
 }
 
 static void lsetCommand(redisClient *c) {
     robj *o;
     int index = atoi(c->argv[2]->ptr);
-    
-    o = lookupKeyWrite(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.nokeyerr);
+    list *list;
+    listNode *ln;
+
+    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr)) == NULL ||
+        checkType(c,o,REDIS_LIST)) return;
+    list = o->ptr;
+
+    ln = listIndex(list, index);
+    if (ln == NULL) {
+        addReply(c,shared.outofrangeerr);
     } else {
-        if (o->type != REDIS_LIST) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            list *list = o->ptr;
-            listNode *ln;
-            
-            ln = listIndex(list, index);
-            if (ln == NULL) {
-                addReply(c,shared.outofrangeerr);
-            } else {
-                robj *ele = listNodeValue(ln);
+        robj *ele = listNodeValue(ln);
 
-                decrRefCount(ele);
-                listNodeValue(ln) = c->argv[3];
-                incrRefCount(c->argv[3]);
-                addReply(c,shared.ok);
-                server.dirty++;
-            }
-        }
+        decrRefCount(ele);
+        listNodeValue(ln) = c->argv[3];
+        incrRefCount(c->argv[3]);
+        addReply(c,shared.ok);
+        server.dirty++;
     }
 }
 
 static void popGenericCommand(redisClient *c, int where) {
     robj *o;
+    list *list;
+    listNode *ln;
 
-    o = lookupKeyWrite(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.nullbulk);
-    } else {
-        if (o->type != REDIS_LIST) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            list *list = o->ptr;
-            listNode *ln;
+    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
+        checkType(c,o,REDIS_LIST)) return;
+    list = o->ptr;
 
-            if (where == REDIS_HEAD)
-                ln = listFirst(list);
-            else
-                ln = listLast(list);
+    if (where == REDIS_HEAD)
+        ln = listFirst(list);
+    else
+        ln = listLast(list);
 
-            if (ln == NULL) {
-                addReply(c,shared.nullbulk);
-            } else {
-                robj *ele = listNodeValue(ln);
-                addReplyBulkLen(c,ele);
-                addReply(c,ele);
-                addReply(c,shared.crlf);
-                listDelNode(list,ln);
-                server.dirty++;
-            }
-        }
+    if (ln == NULL) {
+        addReply(c,shared.nullbulk);
+    } else {
+        robj *ele = listNodeValue(ln);
+        addReplyBulk(c,ele);
+        listDelNode(list,ln);
+        server.dirty++;
     }
 }
 
@@ -4236,46 +4380,39 @@ static void lrangeCommand(redisClient *c) {
     robj *o;
     int start = atoi(c->argv[2]->ptr);
     int end = atoi(c->argv[3]->ptr);
+    int llen;
+    int rangelen, j;
+    list *list;
+    listNode *ln;
+    robj *ele;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullmultibulk)) == NULL ||
+        checkType(c,o,REDIS_LIST)) return;
+    list = o->ptr;
+    llen = listLength(list);
+
+    /* convert negative indexes */
+    if (start < 0) start = llen+start;
+    if (end < 0) end = llen+end;
+    if (start < 0) start = 0;
+    if (end < 0) end = 0;
+
+    /* indexes sanity checks */
+    if (start > end || start >= llen) {
+        /* Out of range start or start > end result in empty list */
+        addReply(c,shared.emptymultibulk);
+        return;
+    }
+    if (end >= llen) end = llen-1;
+    rangelen = (end-start)+1;
 
-    o = lookupKeyRead(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.nullmultibulk);
-    } else {
-        if (o->type != REDIS_LIST) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            list *list = o->ptr;
-            listNode *ln;
-            int llen = listLength(list);
-            int rangelen, j;
-            robj *ele;
-
-            /* convert negative indexes */
-            if (start < 0) start = llen+start;
-            if (end < 0) end = llen+end;
-            if (start < 0) start = 0;
-            if (end < 0) end = 0;
-
-            /* indexes sanity checks */
-            if (start > end || start >= llen) {
-                /* Out of range start or start > end result in empty list */
-                addReply(c,shared.emptymultibulk);
-                return;
-            }
-            if (end >= llen) end = llen-1;
-            rangelen = (end-start)+1;
-
-            /* Return the result in form of a multi-bulk reply */
-            ln = listIndex(list, start);
-            addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",rangelen));
-            for (j = 0; j < rangelen; j++) {
-                ele = listNodeValue(ln);
-                addReplyBulkLen(c,ele);
-                addReply(c,ele);
-                addReply(c,shared.crlf);
-                ln = ln->next;
-            }
-        }
+    /* Return the result in form of a multi-bulk reply */
+    ln = listIndex(list, start);
+    addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",rangelen));
+    for (j = 0; j < rangelen; j++) {
+        ele = listNodeValue(ln);
+        addReplyBulk(c,ele);
+        ln = ln->next;
     }
 }
 
@@ -4283,87 +4420,76 @@ static void ltrimCommand(redisClient *c) {
     robj *o;
     int start = atoi(c->argv[2]->ptr);
     int end = atoi(c->argv[3]->ptr);
-    
-    o = lookupKeyWrite(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.ok);
+    int llen;
+    int j, ltrim, rtrim;
+    list *list;
+    listNode *ln;
+
+    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.ok)) == NULL ||
+        checkType(c,o,REDIS_LIST)) return;
+    list = o->ptr;
+    llen = listLength(list);
+
+    /* convert negative indexes */
+    if (start < 0) start = llen+start;
+    if (end < 0) end = llen+end;
+    if (start < 0) start = 0;
+    if (end < 0) end = 0;
+
+    /* indexes sanity checks */
+    if (start > end || start >= llen) {
+        /* Out of range start or start > end result in empty list */
+        ltrim = llen;
+        rtrim = 0;
     } else {
-        if (o->type != REDIS_LIST) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            list *list = o->ptr;
-            listNode *ln;
-            int llen = listLength(list);
-            int j, ltrim, rtrim;
-
-            /* convert negative indexes */
-            if (start < 0) start = llen+start;
-            if (end < 0) end = llen+end;
-            if (start < 0) start = 0;
-            if (end < 0) end = 0;
-
-            /* indexes sanity checks */
-            if (start > end || start >= llen) {
-                /* Out of range start or start > end result in empty list */
-                ltrim = llen;
-                rtrim = 0;
-            } else {
-                if (end >= llen) end = llen-1;
-                ltrim = start;
-                rtrim = llen-end-1;
-            }
+        if (end >= llen) end = llen-1;
+        ltrim = start;
+        rtrim = llen-end-1;
+    }
 
-            /* Remove list elements to perform the trim */
-            for (j = 0; j < ltrim; j++) {
-                ln = listFirst(list);
-                listDelNode(list,ln);
-            }
-            for (j = 0; j < rtrim; j++) {
-                ln = listLast(list);
-                listDelNode(list,ln);
-            }
-            server.dirty++;
-            addReply(c,shared.ok);
-        }
+    /* Remove list elements to perform the trim */
+    for (j = 0; j < ltrim; j++) {
+        ln = listFirst(list);
+        listDelNode(list,ln);
     }
+    for (j = 0; j < rtrim; j++) {
+        ln = listLast(list);
+        listDelNode(list,ln);
+    }
+    server.dirty++;
+    addReply(c,shared.ok);
 }
 
 static void lremCommand(redisClient *c) {
     robj *o;
-    
-    o = lookupKeyWrite(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.czero);
-    } else {
-        if (o->type != REDIS_LIST) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            list *list = o->ptr;
-            listNode *ln, *next;
-            int toremove = atoi(c->argv[2]->ptr);
-            int removed = 0;
-            int fromtail = 0;
-
-            if (toremove < 0) {
-                toremove = -toremove;
-                fromtail = 1;
-            }
-            ln = fromtail ? list->tail : list->head;
-            while (ln) {
-                robj *ele = listNodeValue(ln);
-
-                next = fromtail ? ln->prev : ln->next;
-                if (compareStringObjects(ele,c->argv[3]) == 0) {
-                    listDelNode(list,ln);
-                    server.dirty++;
-                    removed++;
-                    if (toremove && removed == toremove) break;
-                }
-                ln = next;
-            }
-            addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",removed));
+    list *list;
+    listNode *ln, *next;
+    int toremove = atoi(c->argv[2]->ptr);
+    int removed = 0;
+    int fromtail = 0;
+
+    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,REDIS_LIST)) return;
+    list = o->ptr;
+
+    if (toremove < 0) {
+        toremove = -toremove;
+        fromtail = 1;
+    }
+    ln = fromtail ? list->tail : list->head;
+    while (ln) {
+        robj *ele = listNodeValue(ln);
+
+        next = fromtail ? ln->prev : ln->next;
+        if (compareStringObjects(ele,c->argv[3]) == 0) {
+            listDelNode(list,ln);
+            server.dirty++;
+            removed++;
+            if (toremove && removed == toremove) break;
         }
+        ln = next;
     }
+    addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",removed));
 }
 
 /* This is the semantic of this command:
@@ -4383,57 +4509,49 @@ static void lremCommand(redisClient *c) {
  */
 static void rpoplpushcommand(redisClient *c) {
     robj *sobj;
+    list *srclist;
+    listNode *ln;
 
-    sobj = lookupKeyWrite(c->db,c->argv[1]);
-    if (sobj == NULL) {
+    if ((sobj = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
+        checkType(c,sobj,REDIS_LIST)) return;
+    srclist = sobj->ptr;
+    ln = listLast(srclist);
+
+    if (ln == NULL) {
         addReply(c,shared.nullbulk);
     } else {
-        if (sobj->type != REDIS_LIST) {
+        robj *dobj = lookupKeyWrite(c->db,c->argv[2]);
+        robj *ele = listNodeValue(ln);
+        list *dstlist;
+
+        if (dobj && dobj->type != REDIS_LIST) {
             addReply(c,shared.wrongtypeerr);
-        } else {
-            list *srclist = sobj->ptr;
-            listNode *ln = listLast(srclist);
+            return;
+        }
 
-            if (ln == NULL) {
-                addReply(c,shared.nullbulk);
-            } else {
-                robj *dobj = lookupKeyWrite(c->db,c->argv[2]);
-                robj *ele = listNodeValue(ln);
-                list *dstlist;
+        /* Add the element to the target list (unless it's directly
+         * passed to some BLPOP-ing client */
+        if (!handleClientsWaitingListPush(c,c->argv[2],ele)) {
+            if (dobj == NULL) {
+                /* Create the list if the key does not exist */
+                dobj = createListObject();
+                dictAdd(c->db->dict,c->argv[2],dobj);
+                incrRefCount(c->argv[2]);
+            }
+            dstlist = dobj->ptr;
+            listAddNodeHead(dstlist,ele);
+            incrRefCount(ele);
+        }
 
-                if (dobj && dobj->type != REDIS_LIST) {
-                    addReply(c,shared.wrongtypeerr);
-                    return;
-                }
+        /* Send the element to the client as reply as well */
+        addReplyBulk(c,ele);
 
-                /* Add the element to the target list (unless it's directly
-                 * passed to some BLPOP-ing client */
-                if (!handleClientsWaitingListPush(c,c->argv[2],ele)) {
-                    if (dobj == NULL) {
-                        /* Create the list if the key does not exist */
-                        dobj = createListObject();
-                        dictAdd(c->db->dict,c->argv[2],dobj);
-                        incrRefCount(c->argv[2]);
-                    }
-                    dstlist = dobj->ptr;
-                    listAddNodeHead(dstlist,ele);
-                    incrRefCount(ele);
-                }
-
-                /* Send the element to the client as reply as well */
-                addReplyBulkLen(c,ele);
-                addReply(c,ele);
-                addReply(c,shared.crlf);
-
-                /* Finally remove the element from the source list */
-                listDelNode(srclist,ln);
-                server.dirty++;
-            }
-        }
+        /* Finally remove the element from the source list */
+        listDelNode(srclist,ln);
+        server.dirty++;
     }
 }
 
-
 /* ==================================== Sets ================================ */
 
 static void saddCommand(redisClient *c) {
@@ -4462,21 +4580,15 @@ static void saddCommand(redisClient *c) {
 static void sremCommand(redisClient *c) {
     robj *set;
 
-    set = lookupKeyWrite(c->db,c->argv[1]);
-    if (set == NULL) {
-        addReply(c,shared.czero);
+    if ((set = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,set,REDIS_SET)) return;
+
+    if (dictDelete(set->ptr,c->argv[2]) == DICT_OK) {
+        server.dirty++;
+        if (htNeedsResize(set->ptr)) dictResize(set->ptr);
+        addReply(c,shared.cone);
     } else {
-        if (set->type != REDIS_SET) {
-            addReply(c,shared.wrongtypeerr);
-            return;
-        }
-        if (dictDelete(set->ptr,c->argv[2]) == DICT_OK) {
-            server.dirty++;
-            if (htNeedsResize(set->ptr)) dictResize(set->ptr);
-            addReply(c,shared.cone);
-        } else {
-            addReply(c,shared.czero);
-        }
+        addReply(c,shared.czero);
     }
 }
 
@@ -4518,65 +4630,43 @@ static void smoveCommand(redisClient *c) {
 static void sismemberCommand(redisClient *c) {
     robj *set;
 
-    set = lookupKeyRead(c->db,c->argv[1]);
-    if (set == NULL) {
+    if ((set = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,set,REDIS_SET)) return;
+
+    if (dictFind(set->ptr,c->argv[2]))
+        addReply(c,shared.cone);
+    else
         addReply(c,shared.czero);
-    } else {
-        if (set->type != REDIS_SET) {
-            addReply(c,shared.wrongtypeerr);
-            return;
-        }
-        if (dictFind(set->ptr,c->argv[2]))
-            addReply(c,shared.cone);
-        else
-            addReply(c,shared.czero);
-    }
 }
 
 static void scardCommand(redisClient *c) {
     robj *o;
     dict *s;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,REDIS_SET)) return;
     
-    o = lookupKeyRead(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.czero);
-        return;
-    } else {
-        if (o->type != REDIS_SET) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            s = o->ptr;
-            addReplySds(c,sdscatprintf(sdsempty(),":%lu\r\n",
-                dictSize(s)));
-        }
-    }
+    s = o->ptr;
+    addReplyUlong(c,dictSize(s));
 }
 
 static void spopCommand(redisClient *c) {
     robj *set;
     dictEntry *de;
 
-    set = lookupKeyWrite(c->db,c->argv[1]);
-    if (set == NULL) {
+    if ((set = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
+        checkType(c,set,REDIS_SET)) return;
+
+    de = dictGetRandomKey(set->ptr);
+    if (de == NULL) {
         addReply(c,shared.nullbulk);
     } else {
-        if (set->type != REDIS_SET) {
-            addReply(c,shared.wrongtypeerr);
-            return;
-        }
-        de = dictGetRandomKey(set->ptr);
-        if (de == NULL) {
-            addReply(c,shared.nullbulk);
-        } else {
-            robj *ele = dictGetEntryKey(de);
+        robj *ele = dictGetEntryKey(de);
 
-            addReplyBulkLen(c,ele);
-            addReply(c,ele);
-            addReply(c,shared.crlf);
-            dictDelete(set->ptr,ele);
-            if (htNeedsResize(set->ptr)) dictResize(set->ptr);
-            server.dirty++;
-        }
+        addReplyBulk(c,ele);
+        dictDelete(set->ptr,ele);
+        if (htNeedsResize(set->ptr)) dictResize(set->ptr);
+        server.dirty++;
     }
 }
 
@@ -4584,24 +4674,16 @@ static void srandmemberCommand(redisClient *c) {
     robj *set;
     dictEntry *de;
 
-    set = lookupKeyRead(c->db,c->argv[1]);
-    if (set == NULL) {
+    if ((set = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
+        checkType(c,set,REDIS_SET)) return;
+
+    de = dictGetRandomKey(set->ptr);
+    if (de == NULL) {
         addReply(c,shared.nullbulk);
     } else {
-        if (set->type != REDIS_SET) {
-            addReply(c,shared.wrongtypeerr);
-            return;
-        }
-        de = dictGetRandomKey(set->ptr);
-        if (de == NULL) {
-            addReply(c,shared.nullbulk);
-        } else {
-            robj *ele = dictGetEntryKey(de);
+        robj *ele = dictGetEntryKey(de);
 
-            addReplyBulkLen(c,ele);
-            addReply(c,ele);
-            addReply(c,shared.crlf);
-        }
+        addReplyBulk(c,ele);
     }
 }
 
@@ -4675,9 +4757,7 @@ static void sinterGenericCommand(redisClient *c, robj **setskeys, unsigned long
             continue; /* at least one set does not contain the member */
         ele = dictGetEntryKey(de);
         if (!dstkey) {
-            addReplyBulkLen(c,ele);
-            addReply(c,ele);
-            addReply(c,shared.crlf);
+            addReplyBulk(c,ele);
             cardinality++;
         } else {
             dictAdd(dstset->ptr,ele,NULL);
@@ -4713,6 +4793,7 @@ static void sinterstoreCommand(redisClient *c) {
 
 #define REDIS_OP_UNION 0
 #define REDIS_OP_DIFF 1
+#define REDIS_OP_INTER 2
 
 static void sunionDiffGenericCommand(redisClient *c, robj **setskeys, int setsnum, robj *dstkey, int op) {
     dict **dv = zmalloc(sizeof(dict*)*setsnum);
@@ -4781,9 +4862,7 @@ static void sunionDiffGenericCommand(redisClient *c, robj **setskeys, int setsnu
             robj *ele;
 
             ele = dictGetEntryKey(de);
-            addReplyBulkLen(c,ele);
-            addReply(c,ele);
-            addReply(c,shared.crlf);
+            addReplyBulk(c,ele);
         }
         dictReleaseIterator(di);
     } else {
@@ -4844,7 +4923,8 @@ static zskiplistNode *zslCreateNode(int level, double score, robj *obj) {
     zskiplistNode *zn = zmalloc(sizeof(*zn));
 
     zn->forward = zmalloc(sizeof(zskiplistNode*) * level);
-    zn->span = zmalloc(sizeof(unsigned int) * level);
+    if (level > 0)
+        zn->span = zmalloc(sizeof(unsigned int) * (level - 1));
     zn->score = score;
     zn->obj = obj;
     return zn;
@@ -4860,7 +4940,10 @@ static zskiplist *zslCreate(void) {
     zsl->header = zslCreateNode(ZSKIPLIST_MAXLEVEL,0,NULL);
     for (j = 0; j < ZSKIPLIST_MAXLEVEL; j++) {
         zsl->header->forward[j] = NULL;
-        zsl->header->span[j] = 0;
+
+        /* span has space for ZSKIPLIST_MAXLEVEL-1 elements */
+        if (j < ZSKIPLIST_MAXLEVEL-1)
+            zsl->header->span[j] = 0;
     }
     zsl->header->backward = NULL;
     zsl->tail = NULL;
@@ -4897,19 +4980,19 @@ static int zslRandomLevel(void) {
 
 static void zslInsert(zskiplist *zsl, double score, robj *obj) {
     zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x;
-    unsigned int span[ZSKIPLIST_MAXLEVEL];
+    unsigned int rank[ZSKIPLIST_MAXLEVEL];
     int i, level;
 
     x = zsl->header;
     for (i = zsl->level-1; i >= 0; i--) {
-        /* store span that is crossed to reach the insert position */
-        span[i] = i == (zsl->level-1) ? 0 : span[i+1];
+        /* store rank that is crossed to reach the insert position */
+        rank[i] = i == (zsl->level-1) ? 0 : rank[i+1];
 
         while (x->forward[i] &&
             (x->forward[i]->score < score ||
                 (x->forward[i]->score == score &&
                 compareStringObjects(x->forward[i]->obj,obj) < 0))) {
-            span[i] += x->span[i];
+            rank[i] += i > 0 ? x->span[i-1] : 1;
             x = x->forward[i];
         }
         update[i] = x;
@@ -4921,9 +5004,9 @@ static void zslInsert(zskiplist *zsl, double score, robj *obj) {
     level = zslRandomLevel();
     if (level > zsl->level) {
         for (i = zsl->level; i < level; i++) {
-            span[i] = 0;
+            rank[i] = 0;
             update[i] = zsl->header;
-            update[i]->span[i] = zsl->length;
+            update[i]->span[i-1] = zsl->length;
         }
         zsl->level = level;
     }
@@ -4933,13 +5016,15 @@ static void zslInsert(zskiplist *zsl, double score, robj *obj) {
         update[i]->forward[i] = x;
 
         /* update span covered by update[i] as x is inserted here */
-        x->span[i] = update[i]->span[i] - (span[0] - span[i]);
-        update[i]->span[i] = (span[0] - span[i]) + 1;
+        if (i > 0) {
+            x->span[i-1] = update[i]->span[i-1] - (rank[0] - rank[i]);
+            update[i]->span[i-1] = (rank[0] - rank[i]) + 1;
+        }
     }
 
     /* increment span for untouched levels */
     for (i = level; i < zsl->level; i++) {
-        update[i]->span[i]++;
+        update[i]->span[i-1]++;
     }
 
     x->backward = (update[0] == zsl->header) ? NULL : update[0];
@@ -4950,6 +5035,31 @@ static void zslInsert(zskiplist *zsl, double score, robj *obj) {
     zsl->length++;
 }
 
+/* Internal function used by zslDelete, zslDeleteByScore and zslDeleteByRank */
+void zslDeleteNode(zskiplist *zsl, zskiplistNode *x, zskiplistNode **update) {
+    int i;
+    for (i = 0; i < zsl->level; i++) {
+        if (update[i]->forward[i] == x) {
+            if (i > 0) {
+                update[i]->span[i-1] += x->span[i-1] - 1;
+            }
+            update[i]->forward[i] = x->forward[i];
+        } else {
+            /* invariant: i > 0, because update[0]->forward[0]
+             * is always equal to x */
+            update[i]->span[i-1] -= 1;
+        }
+    }
+    if (x->forward[0]) {
+        x->forward[0]->backward = x->backward;
+    } else {
+        zsl->tail = x->backward;
+    }
+    while(zsl->level > 1 && zsl->header->forward[zsl->level-1] == NULL)
+        zsl->level--;
+    zsl->length--;
+}
+
 /* Delete an element with matching score/object from the skiplist. */
 static int zslDelete(zskiplist *zsl, double score, robj *obj) {
     zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x;
@@ -4968,23 +5078,8 @@ static int zslDelete(zskiplist *zsl, double score, robj *obj) {
      * is to find the element with both the right score and object. */
     x = x->forward[0];
     if (x && score == x->score && compareStringObjects(x->obj,obj) == 0) {
-        for (i = 0; i < zsl->level; i++) {
-            if (update[i]->forward[i] == x) {
-                update[i]->span[i] += x->span[i] - 1;
-                update[i]->forward[i] = x->forward[i];
-            } else {
-                update[i]->span[i] -= 1;
-            }
-        }
-        if (x->forward[0]) {
-            x->forward[0]->backward = x->backward;
-        } else {
-            zsl->tail = x->backward;
-        }
+        zslDeleteNode(zsl, x, update);
         zslFreeNode(x);
-        while(zsl->level > 1 && zsl->header->forward[zsl->level-1] == NULL)
-            zsl->level--;
-        zsl->length--;
         return 1;
     } else {
         return 0; /* not found */
@@ -4996,7 +5091,7 @@ static int zslDelete(zskiplist *zsl, double score, robj *obj) {
  * Min and mx are inclusive, so a score >= min || score <= max is deleted.
  * Note that this function takes the reference to the hash table view of the
  * sorted set, in order to remove the elements from the hash table too. */
-static unsigned long zslDeleteRange(zskiplist *zsl, double min, double max, dict *dict) {
+static unsigned long zslDeleteRangeByScore(zskiplist *zsl, double min, double max, dict *dict) {
     zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x;
     unsigned long removed = 0;
     int i;
@@ -5011,31 +5106,44 @@ static unsigned long zslDeleteRange(zskiplist *zsl, double min, double max, dict
      * is to find the element with both the right score and object. */
     x = x->forward[0];
     while (x && x->score <= max) {
-        zskiplistNode *next;
+        zskiplistNode *next = x->forward[0];
+        zslDeleteNode(zsl, x, update);
+        dictDelete(dict,x->obj);
+        zslFreeNode(x);
+        removed++;
+        x = next;
+    }
+    return removed; /* not found */
+}
 
-        for (i = 0; i < zsl->level; i++) {
-            if (update[i]->forward[i] == x) {
-                update[i]->span[i] += x->span[i] - 1;
-                update[i]->forward[i] = x->forward[i];
-            } else {
-                update[i]->span[i] -= 1;
-            }
-        }
-        if (x->forward[0]) {
-            x->forward[0]->backward = x->backward;
-        } else {
-            zsl->tail = x->backward;
+/* Delete all the elements with rank between start and end from the skiplist.
+ * Start and end are inclusive. Note that start and end need to be 1-based */
+static unsigned long zslDeleteRangeByRank(zskiplist *zsl, unsigned int start, unsigned int end, dict *dict) {
+    zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x;
+    unsigned long traversed = 0, removed = 0;
+    int i;
+
+    x = zsl->header;
+    for (i = zsl->level-1; i >= 0; i--) {
+        while (x->forward[i] && (traversed + (i > 0 ? x->span[i-1] : 1)) < start) {
+            traversed += i > 0 ? x->span[i-1] : 1;
+            x = x->forward[i];
         }
-        next = x->forward[0];
+        update[i] = x;
+    }
+
+    traversed++;
+    x = x->forward[0];
+    while (x && traversed <= end) {
+        zskiplistNode *next = x->forward[0];
+        zslDeleteNode(zsl, x, update);
         dictDelete(dict,x->obj);
         zslFreeNode(x);
-        while(zsl->level > 1 && zsl->header->forward[zsl->level-1] == NULL)
-            zsl->level--;
-        zsl->length--;
         removed++;
+        traversed++;
         x = next;
     }
-    return removed; /* not found */
+    return removed;
 }
 
 /* Find the first node having a score equal or greater than the specified one.
@@ -5069,7 +5177,7 @@ static unsigned long zslGetRank(zskiplist *zsl, double score, robj *o) {
             (x->forward[i]->score < score ||
                 (x->forward[i]->score == score &&
                 compareStringObjects(x->forward[i]->obj,o) <= 0))) {
-            rank += x->span[i];
+            rank += i > 0 ? x->span[i-1] : 1;
             x = x->forward[i];
         }
 
@@ -5081,6 +5189,26 @@ static unsigned long zslGetRank(zskiplist *zsl, double score, robj *o) {
     return 0;
 }
 
+/* Finds an element by its rank. The rank argument needs to be 1-based. */
+zskiplistNode* zslGetElementByRank(zskiplist *zsl, unsigned long rank) {
+    zskiplistNode *x;
+    unsigned long traversed = 0;
+    int i;
+
+    x = zsl->header;
+    for (i = zsl->level-1; i >= 0; i--) {
+        while (x->forward[i] && (traversed + (i>0 ? x->span[i-1] : 1)) <= rank)
+        {
+            traversed += i > 0 ? x->span[i-1] : 1;
+            x = x->forward[i];
+        }
+        if (traversed == rank) {
+            return x;
+        }
+    }
+    return NULL;
+}
+
 /* The actual Z-commands implementations */
 
 /* This generic command implements both ZADD and ZINCRBY.
@@ -5181,60 +5309,275 @@ static void zincrbyCommand(redisClient *c) {
 static void zremCommand(redisClient *c) {
     robj *zsetobj;
     zset *zs;
+    dictEntry *de;
+    double *oldscore;
+    int deleted;
 
-    zsetobj = lookupKeyWrite(c->db,c->argv[1]);
-    if (zsetobj == NULL) {
-        addReply(c,shared.czero);
-    } else {
-        dictEntry *de;
-        double *oldscore;
-        int deleted;
-
-        if (zsetobj->type != REDIS_ZSET) {
-            addReply(c,shared.wrongtypeerr);
-            return;
-        }
-        zs = zsetobj->ptr;
-        de = dictFind(zs->dict,c->argv[2]);
-        if (de == NULL) {
-            addReply(c,shared.czero);
-            return;
-        }
-        /* Delete from the skiplist */
-        oldscore = dictGetEntryVal(de);
-        deleted = zslDelete(zs->zsl,*oldscore,c->argv[2]);
-        redisAssert(deleted != 0);
+    if ((zsetobj = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,zsetobj,REDIS_ZSET)) return;
 
-        /* Delete from the hash table */
-        dictDelete(zs->dict,c->argv[2]);
-        if (htNeedsResize(zs->dict)) dictResize(zs->dict);
-        server.dirty++;
-        addReply(c,shared.cone);
+    zs = zsetobj->ptr;
+    de = dictFind(zs->dict,c->argv[2]);
+    if (de == NULL) {
+        addReply(c,shared.czero);
+        return;
     }
+    /* Delete from the skiplist */
+    oldscore = dictGetEntryVal(de);
+    deleted = zslDelete(zs->zsl,*oldscore,c->argv[2]);
+    redisAssert(deleted != 0);
+
+    /* Delete from the hash table */
+    dictDelete(zs->dict,c->argv[2]);
+    if (htNeedsResize(zs->dict)) dictResize(zs->dict);
+    server.dirty++;
+    addReply(c,shared.cone);
 }
 
 static void zremrangebyscoreCommand(redisClient *c) {
     double min = strtod(c->argv[2]->ptr,NULL);
     double max = strtod(c->argv[3]->ptr,NULL);
+    long deleted;
     robj *zsetobj;
     zset *zs;
 
-    zsetobj = lookupKeyWrite(c->db,c->argv[1]);
-    if (zsetobj == NULL) {
+    if ((zsetobj = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,zsetobj,REDIS_ZSET)) return;
+
+    zs = zsetobj->ptr;
+    deleted = zslDeleteRangeByScore(zs->zsl,min,max,zs->dict);
+    if (htNeedsResize(zs->dict)) dictResize(zs->dict);
+    server.dirty += deleted;
+    addReplyLong(c,deleted);
+}
+
+static void zremrangebyrankCommand(redisClient *c) {
+    int start = atoi(c->argv[2]->ptr);
+    int end = atoi(c->argv[3]->ptr);
+    int llen;
+    long deleted;
+    robj *zsetobj;
+    zset *zs;
+
+    if ((zsetobj = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,zsetobj,REDIS_ZSET)) return;
+    zs = zsetobj->ptr;
+    llen = zs->zsl->length;
+
+    /* convert negative indexes */
+    if (start < 0) start = llen+start;
+    if (end < 0) end = llen+end;
+    if (start < 0) start = 0;
+    if (end < 0) end = 0;
+
+    /* indexes sanity checks */
+    if (start > end || start >= llen) {
         addReply(c,shared.czero);
+        return;
+    }
+    if (end >= llen) end = llen-1;
+
+    /* increment start and end because zsl*Rank functions
+     * use 1-based rank */
+    deleted = zslDeleteRangeByRank(zs->zsl,start+1,end+1,zs->dict);
+    if (htNeedsResize(zs->dict)) dictResize(zs->dict);
+    server.dirty += deleted;
+    addReplyLong(c, deleted);
+}
+
+typedef struct {
+    dict *dict;
+    double weight;
+} zsetopsrc;
+
+static int qsortCompareZsetopsrcByCardinality(const void *s1, const void *s2) {
+    zsetopsrc *d1 = (void*) s1, *d2 = (void*) s2;
+    unsigned long size1, size2;
+    size1 = d1->dict ? dictSize(d1->dict) : 0;
+    size2 = d2->dict ? dictSize(d2->dict) : 0;
+    return size1 - size2;
+}
+
+#define REDIS_AGGR_SUM 1
+#define REDIS_AGGR_MIN 2
+#define REDIS_AGGR_MAX 3
+
+inline static void zunionInterAggregate(double *target, double val, int aggregate) {
+    if (aggregate == REDIS_AGGR_SUM) {
+        *target = *target + val;
+    } else if (aggregate == REDIS_AGGR_MIN) {
+        *target = val < *target ? val : *target;
+    } else if (aggregate == REDIS_AGGR_MAX) {
+        *target = val > *target ? val : *target;
     } else {
-        long deleted;
+        /* safety net */
+        redisAssert(0 != 0);
+    }
+}
 
-        if (zsetobj->type != REDIS_ZSET) {
-            addReply(c,shared.wrongtypeerr);
-            return;
+static void zunionInterGenericCommand(redisClient *c, robj *dstkey, int op) {
+    int i, j, zsetnum;
+    int aggregate = REDIS_AGGR_SUM;
+    zsetopsrc *src;
+    robj *dstobj;
+    zset *dstzset;
+    dictIterator *di;
+    dictEntry *de;
+
+    /* expect zsetnum input keys to be given */
+    zsetnum = atoi(c->argv[2]->ptr);
+    if (zsetnum < 1) {
+        addReplySds(c,sdsnew("-ERR at least 1 input key is needed for ZUNION/ZINTER\r\n"));
+        return;
+    }
+
+    /* test if the expected number of keys would overflow */
+    if (3+zsetnum > c->argc) {
+        addReply(c,shared.syntaxerr);
+        return;
+    }
+
+    /* read keys to be used for input */
+    src = zmalloc(sizeof(zsetopsrc) * zsetnum);
+    for (i = 0, j = 3; i < zsetnum; i++, j++) {
+        robj *zsetobj = lookupKeyWrite(c->db,c->argv[j]);
+        if (!zsetobj) {
+            src[i].dict = NULL;
+        } else {
+            if (zsetobj->type != REDIS_ZSET) {
+                zfree(src);
+                addReply(c,shared.wrongtypeerr);
+                return;
+            }
+            src[i].dict = ((zset*)zsetobj->ptr)->dict;
+        }
+
+        /* default all weights to 1 */
+        src[i].weight = 1.0;
+    }
+
+    /* parse optional extra arguments */
+    if (j < c->argc) {
+        int remaining = c->argc - j;
+
+        while (remaining) {
+            if (remaining >= (zsetnum + 1) && !strcasecmp(c->argv[j]->ptr,"weights")) {
+                j++; remaining--;
+                for (i = 0; i < zsetnum; i++, j++, remaining--) {
+                    src[i].weight = strtod(c->argv[j]->ptr, NULL);
+                }
+            } else if (remaining >= 2 && !strcasecmp(c->argv[j]->ptr,"aggregate")) {
+                j++; remaining--;
+                if (!strcasecmp(c->argv[j]->ptr,"sum")) {
+                    aggregate = REDIS_AGGR_SUM;
+                } else if (!strcasecmp(c->argv[j]->ptr,"min")) {
+                    aggregate = REDIS_AGGR_MIN;
+                } else if (!strcasecmp(c->argv[j]->ptr,"max")) {
+                    aggregate = REDIS_AGGR_MAX;
+                } else {
+                    zfree(src);
+                    addReply(c,shared.syntaxerr);
+                    return;
+                }
+                j++; remaining--;
+            } else {
+                zfree(src);
+                addReply(c,shared.syntaxerr);
+                return;
+            }
+        }
+    }
+
+    /* sort sets from the smallest to largest, this will improve our
+     * algorithm's performance */
+    qsort(src,zsetnum,sizeof(zsetopsrc), qsortCompareZsetopsrcByCardinality);
+
+    dstobj = createZsetObject();
+    dstzset = dstobj->ptr;
+
+    if (op == REDIS_OP_INTER) {
+        /* skip going over all entries if the smallest zset is NULL or empty */
+        if (src[0].dict && dictSize(src[0].dict) > 0) {
+            /* precondition: as src[0].dict is non-empty and the zsets are ordered
+             * from small to large, all src[i > 0].dict are non-empty too */
+            di = dictGetIterator(src[0].dict);
+            while((de = dictNext(di)) != NULL) {
+                double *score = zmalloc(sizeof(double)), value;
+                *score = src[0].weight * (*(double*)dictGetEntryVal(de));
+
+                for (j = 1; j < zsetnum; j++) {
+                    dictEntry *other = dictFind(src[j].dict,dictGetEntryKey(de));
+                    if (other) {
+                        value = src[j].weight * (*(double*)dictGetEntryVal(other));
+                        zunionInterAggregate(score, value, aggregate);
+                    } else {
+                        break;
+                    }
+                }
+
+                /* skip entry when not present in every source dict */
+                if (j != zsetnum) {
+                    zfree(score);
+                } else {
+                    robj *o = dictGetEntryKey(de);
+                    dictAdd(dstzset->dict,o,score);
+                    incrRefCount(o); /* added to dictionary */
+                    zslInsert(dstzset->zsl,*score,o);
+                    incrRefCount(o); /* added to skiplist */
+                }
+            }
+            dictReleaseIterator(di);
+        }
+    } else if (op == REDIS_OP_UNION) {
+        for (i = 0; i < zsetnum; i++) {
+            if (!src[i].dict) continue;
+
+            di = dictGetIterator(src[i].dict);
+            while((de = dictNext(di)) != NULL) {
+                /* skip key when already processed */
+                if (dictFind(dstzset->dict,dictGetEntryKey(de)) != NULL) continue;
+
+                double *score = zmalloc(sizeof(double)), value;
+                *score = src[i].weight * (*(double*)dictGetEntryVal(de));
+
+                /* because the zsets are sorted by size, its only possible
+                 * for sets at larger indices to hold this entry */
+                for (j = (i+1); j < zsetnum; j++) {
+                    dictEntry *other = dictFind(src[j].dict,dictGetEntryKey(de));
+                    if (other) {
+                        value = src[j].weight * (*(double*)dictGetEntryVal(other));
+                        zunionInterAggregate(score, value, aggregate);
+                    }
+                }
+
+                robj *o = dictGetEntryKey(de);
+                dictAdd(dstzset->dict,o,score);
+                incrRefCount(o); /* added to dictionary */
+                zslInsert(dstzset->zsl,*score,o);
+                incrRefCount(o); /* added to skiplist */
+            }
+            dictReleaseIterator(di);
         }
-        zs = zsetobj->ptr;
-        deleted = zslDeleteRange(zs->zsl,min,max,zs->dict);
-        if (htNeedsResize(zs->dict)) dictResize(zs->dict);
-        server.dirty += deleted;
-        addReplySds(c,sdscatprintf(sdsempty(),":%lu\r\n",deleted));
+    } else {
+        /* unknown operator */
+        redisAssert(op == REDIS_OP_INTER || op == REDIS_OP_UNION);
     }
+
+    deleteKey(c->db,dstkey);
+    dictAdd(c->db->dict,dstkey,dstobj);
+    incrRefCount(dstkey);
+
+    addReplyLong(c, dstzset->zsl->length);
+    server.dirty++;
+    zfree(src);
+}
+
+static void zunionCommand(redisClient *c) {
+    zunionInterGenericCommand(c,c->argv[1], REDIS_OP_UNION);
+}
+
+static void zinterCommand(redisClient *c) {
+    zunionInterGenericCommand(c,c->argv[1], REDIS_OP_INTER);
 }
 
 static void zrangeGenericCommand(redisClient *c, int reverse) {
@@ -5242,6 +5585,12 @@ static void zrangeGenericCommand(redisClient *c, int reverse) {
     int start = atoi(c->argv[2]->ptr);
     int end = atoi(c->argv[3]->ptr);
     int withscores = 0;
+    int llen;
+    int rangelen, j;
+    zset *zsetobj;
+    zskiplist *zsl;
+    zskiplistNode *ln;
+    robj *ele;
 
     if (c->argc == 5 && !strcasecmp(c->argv[4]->ptr,"withscores")) {
         withscores = 1;
@@ -5250,59 +5599,45 @@ static void zrangeGenericCommand(redisClient *c, int reverse) {
         return;
     }
 
-    o = lookupKeyRead(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.nullmultibulk);
-    } else {
-        if (o->type != REDIS_ZSET) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            zset *zsetobj = o->ptr;
-            zskiplist *zsl = zsetobj->zsl;
-            zskiplistNode *ln;
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullmultibulk)) == NULL ||
+        checkType(c,o,REDIS_ZSET)) return;
+    zsetobj = o->ptr;
+    zsl = zsetobj->zsl;
+    llen = zsl->length;
 
-            int llen = zsl->length;
-            int rangelen, j;
-            robj *ele;
+    /* convert negative indexes */
+    if (start < 0) start = llen+start;
+    if (end < 0) end = llen+end;
+    if (start < 0) start = 0;
+    if (end < 0) end = 0;
 
-            /* convert negative indexes */
-            if (start < 0) start = llen+start;
-            if (end < 0) end = llen+end;
-            if (start < 0) start = 0;
-            if (end < 0) end = 0;
+    /* indexes sanity checks */
+    if (start > end || start >= llen) {
+        /* Out of range start or start > end result in empty list */
+        addReply(c,shared.emptymultibulk);
+        return;
+    }
+    if (end >= llen) end = llen-1;
+    rangelen = (end-start)+1;
 
-            /* indexes sanity checks */
-            if (start > end || start >= llen) {
-                /* Out of range start or start > end result in empty list */
-                addReply(c,shared.emptymultibulk);
-                return;
-            }
-            if (end >= llen) end = llen-1;
-            rangelen = (end-start)+1;
-
-            /* Return the result in form of a multi-bulk reply */
-            if (reverse) {
-                ln = zsl->tail;
-                while (start--)
-                    ln = ln->backward;
-            } else {
-                ln = zsl->header->forward[0];
-                while (start--)
-                    ln = ln->forward[0];
-            }
+    /* check if starting point is trivial, before searching
+     * the element in log(N) time */
+    if (reverse) {
+        ln = start == 0 ? zsl->tail : zslGetElementByRank(zsl, llen-start);
+    } else {
+        ln = start == 0 ?
+            zsl->header->forward[0] : zslGetElementByRank(zsl, start+1);
+    }
 
-            addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",
-                withscores ? (rangelen*2) : rangelen));
-            for (j = 0; j < rangelen; j++) {
-                ele = ln->obj;
-                addReplyBulkLen(c,ele);
-                addReply(c,ele);
-                addReply(c,shared.crlf);
-                if (withscores)
-                    addReplyDouble(c,ln->score);
-                ln = reverse ? ln->backward : ln->forward[0];
-            }
-        }
+    /* Return the result in form of a multi-bulk reply */
+    addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",
+        withscores ? (rangelen*2) : rangelen));
+    for (j = 0; j < rangelen; j++) {
+        ele = ln->obj;
+        addReplyBulk(c,ele);
+        if (withscores)
+            addReplyDouble(c,ln->score);
+        ln = reverse ? ln->backward : ln->forward[0];
     }
 }
 
@@ -5412,9 +5747,7 @@ static void genericZrangebyscoreCommand(redisClient *c, int justcount) {
                 if (limit == 0) break;
                 if (!justcount) {
                     ele = ln->obj;
-                    addReplyBulkLen(c,ele);
-                    addReply(c,ele);
-                    addReply(c,shared.crlf);
+                    addReplyBulk(c,ele);
                     if (withscores)
                         addReplyDouble(c,ln->score);
                 }
@@ -5443,77 +5776,308 @@ static void zcountCommand(redisClient *c) {
 static void zcardCommand(redisClient *c) {
     robj *o;
     zset *zs;
-    
-    o = lookupKeyRead(c->db,c->argv[1]);
-    if (o == NULL) {
-        addReply(c,shared.czero);
-        return;
-    } else {
-        if (o->type != REDIS_ZSET) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            zs = o->ptr;
-            addReplySds(c,sdscatprintf(sdsempty(),":%lu\r\n",zs->zsl->length));
-        }
-    }
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,REDIS_ZSET)) return;
+
+    zs = o->ptr;
+    addReplyUlong(c,zs->zsl->length);
 }
 
 static void zscoreCommand(redisClient *c) {
     robj *o;
     zset *zs;
-    
-    o = lookupKeyRead(c->db,c->argv[1]);
-    if (o == NULL) {
+    dictEntry *de;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
+        checkType(c,o,REDIS_ZSET)) return;
+
+    zs = o->ptr;
+    de = dictFind(zs->dict,c->argv[2]);
+    if (!de) {
         addReply(c,shared.nullbulk);
-        return;
     } else {
-        if (o->type != REDIS_ZSET) {
-            addReply(c,shared.wrongtypeerr);
-        } else {
-            dictEntry *de;
+        double *score = dictGetEntryVal(de);
 
-            zs = o->ptr;
-            de = dictFind(zs->dict,c->argv[2]);
-            if (!de) {
-                addReply(c,shared.nullbulk);
-            } else {
-                double *score = dictGetEntryVal(de);
+        addReplyDouble(c,*score);
+    }
+}
 
-                addReplyDouble(c,*score);
-            }
+static void zrankGenericCommand(redisClient *c, int reverse) {
+    robj *o;
+    zset *zs;
+    zskiplist *zsl;
+    dictEntry *de;
+    unsigned long rank;
+    double *score;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
+        checkType(c,o,REDIS_ZSET)) return;
+
+    zs = o->ptr;
+    zsl = zs->zsl;
+    de = dictFind(zs->dict,c->argv[2]);
+    if (!de) {
+        addReply(c,shared.nullbulk);
+        return;
+    }
+
+    score = dictGetEntryVal(de);
+    rank = zslGetRank(zsl, *score, c->argv[2]);
+    if (rank) {
+        if (reverse) {
+            addReplyLong(c, zsl->length - rank);
+        } else {
+            addReplyLong(c, rank-1);
         }
+    } else {
+        addReply(c,shared.nullbulk);
     }
 }
 
 static void zrankCommand(redisClient *c) {
-    robj *o;
-    o = lookupKeyRead(c->db,c->argv[1]);
+    zrankGenericCommand(c, 0);
+}
+
+static void zrevrankCommand(redisClient *c) {
+    zrankGenericCommand(c, 1);
+}
+
+/* =================================== Hashes =============================== */
+static void hsetCommand(redisClient *c) {
+    int update = 0;
+    robj *o = lookupKeyWrite(c->db,c->argv[1]);
+
     if (o == NULL) {
-        addReply(c,shared.nullbulk);
-        return;
+        o = createHashObject();
+        dictAdd(c->db->dict,c->argv[1],o);
+        incrRefCount(c->argv[1]);
+    } else {
+        if (o->type != REDIS_HASH) {
+            addReply(c,shared.wrongtypeerr);
+            return;
+        }
     }
-    if (o->type != REDIS_ZSET) {
-        addReply(c,shared.wrongtypeerr);
+    /* We want to convert the zipmap into an hash table right now if the
+     * entry to be added is too big. Note that we check if the object
+     * is integer encoded before to try fetching the length in the test below.
+     * This is because integers are small, but currently stringObjectLen()
+     * performs a slow conversion: not worth it. */
+    if (o->encoding == REDIS_ENCODING_ZIPMAP &&
+        ((c->argv[2]->encoding == REDIS_ENCODING_RAW &&
+          sdslen(c->argv[2]->ptr) > server.hash_max_zipmap_value) ||
+         (c->argv[3]->encoding == REDIS_ENCODING_RAW &&
+          sdslen(c->argv[3]->ptr) > server.hash_max_zipmap_value)))
+    {
+        convertToRealHash(o);
+    }
+
+    if (o->encoding == REDIS_ENCODING_ZIPMAP) {
+        unsigned char *zm = o->ptr;
+        robj *valobj = getDecodedObject(c->argv[3]);
+
+        zm = zipmapSet(zm,c->argv[2]->ptr,sdslen(c->argv[2]->ptr),
+            valobj->ptr,sdslen(valobj->ptr),&update);
+        decrRefCount(valobj);
+        o->ptr = zm;
+
+        /* And here there is the second check for hash conversion...
+         * we want to do it only if the operation was not just an update as
+         * zipmapLen() is O(N). */
+        if (!update && zipmapLen(zm) > server.hash_max_zipmap_entries)
+            convertToRealHash(o);
     } else {
-        zset *zs = o->ptr;
-        zskiplist *zsl = zs->zsl;
-        dictEntry *de;
-        unsigned long rank;
+        tryObjectEncoding(c->argv[2]);
+        /* note that c->argv[3] is already encoded, as the latest arg
+         * of a bulk command is always integer encoded if possible. */
+        if (dictReplace(o->ptr,c->argv[2],c->argv[3])) {
+            incrRefCount(c->argv[2]);
+        } else {
+            update = 1;
+        }
+        incrRefCount(c->argv[3]);
+    }
+    server.dirty++;
+    addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",update == 0));
+}
 
-        de = dictFind(zs->dict,c->argv[2]);
-        if (!de) {
+static void hgetCommand(redisClient *c) {
+    robj *o;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
+        checkType(c,o,REDIS_HASH)) return;
+
+    if (o->encoding == REDIS_ENCODING_ZIPMAP) {
+        unsigned char *zm = o->ptr;
+        unsigned char *val;
+        unsigned int vlen;
+        robj *field;
+
+        field = getDecodedObject(c->argv[2]);
+        if (zipmapGet(zm,field->ptr,sdslen(field->ptr), &val,&vlen)) {
+            addReplySds(c,sdscatprintf(sdsempty(),"$%u\r\n", vlen));
+            addReplySds(c,sdsnewlen(val,vlen));
+            addReply(c,shared.crlf);
+            decrRefCount(field);
+            return;
+        } else {
             addReply(c,shared.nullbulk);
+            decrRefCount(field);
             return;
         }
+    } else {
+        struct dictEntry *de;
 
-        double *score = dictGetEntryVal(de);
-        rank = zslGetRank(zsl, *score, c->argv[2]);
-        if (rank) {
-            addReplyLong(c, rank-1);
-        } else {
+        de = dictFind(o->ptr,c->argv[2]);
+        if (de == NULL) {
             addReply(c,shared.nullbulk);
+        } else {
+            robj *e = dictGetEntryVal(de);
+
+            addReplyBulk(c,e);
+        }
+    }
+}
+
+static void hdelCommand(redisClient *c) {
+    robj *o;
+    int deleted = 0;
+
+    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,REDIS_HASH)) return;
+
+    if (o->encoding == REDIS_ENCODING_ZIPMAP) {
+        robj *field = getDecodedObject(c->argv[2]);
+
+        o->ptr = zipmapDel((unsigned char*) o->ptr,
+            (unsigned char*) field->ptr,
+            sdslen(field->ptr), &deleted);
+        decrRefCount(field);
+    } else {
+        deleted = dictDelete((dict*)o->ptr,c->argv[2]) == DICT_OK;
+    }
+    addReply(c,deleted ? shared.cone : shared.czero);
+}
+
+static void hlenCommand(redisClient *c) {
+    robj *o;
+    unsigned long len;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,REDIS_HASH)) return;
+
+    len = (o->encoding == REDIS_ENCODING_ZIPMAP) ?
+            zipmapLen((unsigned char*)o->ptr) : dictSize((dict*)o->ptr);
+    addReplyUlong(c,len);
+}
+
+#define REDIS_GETALL_KEYS 1
+#define REDIS_GETALL_VALS 2
+static void genericHgetallCommand(redisClient *c, int flags) {
+    robj *o, *lenobj;
+    unsigned long count = 0;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullmultibulk)) == NULL
+        || checkType(c,o,REDIS_HASH)) return;
+
+    lenobj = createObject(REDIS_STRING,NULL);
+    addReply(c,lenobj);
+    decrRefCount(lenobj);
+
+    if (o->encoding == REDIS_ENCODING_ZIPMAP) {
+        unsigned char *p = zipmapRewind(o->ptr);
+        unsigned char *field, *val;
+        unsigned int flen, vlen;
+
+        while((p = zipmapNext(p,&field,&flen,&val,&vlen)) != NULL) {
+            robj *aux;
+
+            if (flags & REDIS_GETALL_KEYS) {
+                aux = createStringObject((char*)field,flen);
+                addReplyBulk(c,aux);
+                decrRefCount(aux);
+                count++;
+            }
+            if (flags & REDIS_GETALL_VALS) {
+                aux = createStringObject((char*)val,vlen);
+                addReplyBulk(c,aux);
+                decrRefCount(aux);
+                count++;
+            }
         }
+    } else {
+        dictIterator *di = dictGetIterator(o->ptr);
+        dictEntry *de;
+
+        while((de = dictNext(di)) != NULL) {
+            robj *fieldobj = dictGetEntryKey(de);
+            robj *valobj = dictGetEntryVal(de);
+
+            if (flags & REDIS_GETALL_KEYS) {
+                addReplyBulk(c,fieldobj);
+                count++;
+            }
+            if (flags & REDIS_GETALL_VALS) {
+                addReplyBulk(c,valobj);
+                count++;
+            }
+        }
+        dictReleaseIterator(di);
     }
+    lenobj->ptr = sdscatprintf(sdsempty(),"*%lu\r\n",count);
+}
+
+static void hkeysCommand(redisClient *c) {
+    genericHgetallCommand(c,REDIS_GETALL_KEYS);
+}
+
+static void hvalsCommand(redisClient *c) {
+    genericHgetallCommand(c,REDIS_GETALL_VALS);
+}
+
+static void hgetallCommand(redisClient *c) {
+    genericHgetallCommand(c,REDIS_GETALL_KEYS|REDIS_GETALL_VALS);
+}
+
+static void hexistsCommand(redisClient *c) {
+    robj *o;
+    int exists = 0;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,REDIS_HASH)) return;
+
+    if (o->encoding == REDIS_ENCODING_ZIPMAP) {
+        robj *field;
+        unsigned char *zm = o->ptr;
+
+        field = getDecodedObject(c->argv[2]);
+        exists = zipmapExists(zm,field->ptr,sdslen(field->ptr));
+        decrRefCount(field);
+    } else {
+        exists = dictFind(o->ptr,c->argv[2]) != NULL;
+    }
+    addReply(c,exists ? shared.cone : shared.czero);
+}
+
+static void convertToRealHash(robj *o) {
+    unsigned char *key, *val, *p, *zm = o->ptr;
+    unsigned int klen, vlen;
+    dict *dict = dictCreate(&hashDictType,NULL);
+
+    assert(o->type == REDIS_HASH && o->encoding != REDIS_ENCODING_HT);
+    p = zipmapRewind(zm);
+    while((p = zipmapNext(p,&key,&klen,&val,&vlen)) != NULL) {
+        robj *keyobj, *valobj;
+
+        keyobj = createStringObject((char*)key,klen);
+        valobj = createStringObject((char*)val,vlen);
+        tryObjectEncoding(keyobj);
+        tryObjectEncoding(valobj);
+        dictAdd(dict,keyobj,valobj);
+    }
+    o->encoding = REDIS_ENCODING_HT;
+    o->ptr = dict;
+    zfree(zm);
 }
 
 /* ========================= Non type-specific commands  ==================== */
@@ -5820,11 +6384,7 @@ static void sortCommand(redisClient *c) {
             listNode *ln;
             listIter li;
 
-            if (!getop) {
-                addReplyBulkLen(c,vector[j].obj);
-                addReply(c,vector[j].obj);
-                addReply(c,shared.crlf);
-            }
+            if (!getop) addReplyBulk(c,vector[j].obj);
             listRewind(operations,&li);
             while((ln = listNext(&li))) {
                 redisSortOperation *sop = ln->value;
@@ -5835,9 +6395,7 @@ static void sortCommand(redisClient *c) {
                     if (!val || val->type != REDIS_STRING) {
                         addReply(c,shared.nullbulk);
                     } else {
-                        addReplyBulkLen(c,val);
-                        addReply(c,val);
-                        addReply(c,shared.crlf);
+                        addReplyBulk(c,val);
                     }
                 } else {
                     redisAssert(sop->type == REDIS_SORT_GET); /* always fails */
@@ -5924,6 +6482,9 @@ static sds genRedisInfoString(void) {
     time_t uptime = time(NULL)-server.stat_starttime;
     int j;
     char hmem[64];
+
+    server.hash_max_zipmap_entries = REDIS_HASH_MAX_ZIPMAP_ENTRIES;
+    server.hash_max_zipmap_value = REDIS_HASH_MAX_ZIPMAP_VALUE;
   
     bytesToHuman(hmem,zmalloc_used_memory());
     info = sdscatprintf(sdsempty(),
@@ -5944,6 +6505,8 @@ static sds genRedisInfoString(void) {
         "bgrewriteaof_in_progress:%d\r\n"
         "total_connections_received:%lld\r\n"
         "total_commands_processed:%lld\r\n"
+        "hash_max_zipmap_entries:%ld\r\n"
+        "hash_max_zipmap_value:%ld\r\n"
         "vm_enabled:%d\r\n"
         "role:%s\r\n"
         ,REDIS_VERSION,
@@ -5963,6 +6526,8 @@ static sds genRedisInfoString(void) {
         server.bgrewritechildpid != -1,
         server.stat_numconnections,
         server.stat_numcommands,
+        server.hash_max_zipmap_entries,
+        server.hash_max_zipmap_value,
         server.vm_enabled != 0,
         server.masterhost == NULL ? "master" : "slave"
     );
@@ -6348,12 +6913,8 @@ static int handleClientsWaitingListPush(redisClient *c, robj *key, robj *ele) {
     receiver = ln->value;
 
     addReplySds(receiver,sdsnew("*2\r\n"));
-    addReplyBulkLen(receiver,key);
-    addReply(receiver,key);
-    addReply(receiver,shared.crlf);
-    addReplyBulkLen(receiver,ele);
-    addReply(receiver,ele);
-    addReply(receiver,shared.crlf);
+    addReplyBulk(receiver,key);
+    addReplyBulk(receiver,ele);
     unblockClientWaitingData(receiver);
     return 1;
 }
@@ -6392,9 +6953,7 @@ static void blockingPopGenericCommand(redisClient *c, int where) {
                      * for us. If this souds like an hack to you it's just
                      * because it is... */
                     addReplySds(c,sdsnew("*2\r\n"));
-                    addReplyBulkLen(c,argv[1]);
-                    addReply(c,argv[1]);
-                    addReply(c,shared.crlf);
+                    addReplyBulk(c,argv[1]);
                     popGenericCommand(c,where);
 
                     /* Fix the client structure with the original stuff */
@@ -6656,9 +7215,9 @@ static void updateSlavesWaitingBgsave(int bgsaveerr) {
 
 static int syncWithMaster(void) {
     char buf[1024], tmpfile[256], authcmd[1024];
-    int dumpsize;
+    long dumpsize;
     int fd = anetTcpConnect(NULL,server.masterhost,server.masterport);
-    int dfd;
+    int dfd, maxtries = 5;
 
     if (fd == -1) {
         redisLog(REDIS_WARNING,"Unable to connect to MASTER: %s",
@@ -6708,11 +7267,16 @@ static int syncWithMaster(void) {
         redisLog(REDIS_WARNING,"Bad protocol from MASTER, the first byte is not '$', are you sure the host and port are right?");
         return REDIS_ERR;
     }
-    dumpsize = atoi(buf+1);
-    redisLog(REDIS_NOTICE,"Receiving %d bytes data dump from MASTER",dumpsize);
+    dumpsize = strtol(buf+1,NULL,10);
+    redisLog(REDIS_NOTICE,"Receiving %ld bytes data dump from MASTER",dumpsize);
     /* Read the bulk write data on a temp file */
-    snprintf(tmpfile,256,"temp-%d.%ld.rdb",(int)time(NULL),(long int)random());
-    dfd = open(tmpfile,O_CREAT|O_WRONLY,0644);
+    while(maxtries--) {
+        snprintf(tmpfile,256,
+            "temp-%d.%ld.rdb",(int)time(NULL),(long int)getpid());
+        dfd = open(tmpfile,O_CREAT|O_WRONLY|O_EXCL,0644);
+        if (dfd != -1) break;
+        sleep(1);
+    }
     if (dfd == -1) {
         close(fd);
         redisLog(REDIS_WARNING,"Opening the temp file needed for MASTER <-> SLAVE synchronization: %s",strerror(errno));
@@ -7052,7 +7616,7 @@ fmterr:
 }
 
 /* Write an object into a file in the bulk format $<count>\r\n<payload>\r\n */
-static int fwriteBulk(FILE *fp, robj *obj) {
+static int fwriteBulkObject(FILE *fp, robj *obj) {
     char buf[128];
     int decrrc = 0;
 
@@ -7077,6 +7641,18 @@ err:
     return 0;
 }
 
+/* Write binary-safe string into a file in the bulkformat
+ * $<count>\r\n<payload>\r\n */
+static int fwriteBulkString(FILE *fp, char *s, unsigned long len) {
+    char buf[128];
+
+    snprintf(buf,sizeof(buf),"$%ld\r\n",(unsigned long)len);
+    if (fwrite(buf,strlen(buf),1,fp) == 0) return 0;
+    if (len && fwrite(s,len,1,fp) == 0) return 0;
+    if (fwrite("\r\n",2,1,fp) == 0) return 0;
+    return 1;
+}
+
 /* Write a double value in bulk format $<count>\r\n<payload>\r\n */
 static int fwriteBulkDouble(FILE *fp, double d) {
     char buf[128], dbuf[128];
@@ -7159,8 +7735,8 @@ static int rewriteAppendOnlyFile(char *filename) {
                 char cmd[]="*3\r\n$3\r\nSET\r\n";
                 if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                 /* Key and value */
-                if (fwriteBulk(fp,key) == 0) goto werr;
-                if (fwriteBulk(fp,o) == 0) goto werr;
+                if (fwriteBulkObject(fp,key) == 0) goto werr;
+                if (fwriteBulkObject(fp,o) == 0) goto werr;
             } else if (o->type == REDIS_LIST) {
                 /* Emit the RPUSHes needed to rebuild the list */
                 list *list = o->ptr;
@@ -7173,8 +7749,8 @@ static int rewriteAppendOnlyFile(char *filename) {
                     robj *eleobj = listNodeValue(ln);
 
                     if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
-                    if (fwriteBulk(fp,key) == 0) goto werr;
-                    if (fwriteBulk(fp,eleobj) == 0) goto werr;
+                    if (fwriteBulkObject(fp,key) == 0) goto werr;
+                    if (fwriteBulkObject(fp,eleobj) == 0) goto werr;
                 }
             } else if (o->type == REDIS_SET) {
                 /* Emit the SADDs needed to rebuild the set */
@@ -7187,8 +7763,8 @@ static int rewriteAppendOnlyFile(char *filename) {
                     robj *eleobj = dictGetEntryKey(de);
 
                     if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
-                    if (fwriteBulk(fp,key) == 0) goto werr;
-                    if (fwriteBulk(fp,eleobj) == 0) goto werr;
+                    if (fwriteBulkObject(fp,key) == 0) goto werr;
+                    if (fwriteBulkObject(fp,eleobj) == 0) goto werr;
                 }
                 dictReleaseIterator(di);
             } else if (o->type == REDIS_ZSET) {
@@ -7203,13 +7779,45 @@ static int rewriteAppendOnlyFile(char *filename) {
                     double *score = dictGetEntryVal(de);
 
                     if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
-                    if (fwriteBulk(fp,key) == 0) goto werr;
+                    if (fwriteBulkObject(fp,key) == 0) goto werr;
                     if (fwriteBulkDouble(fp,*score) == 0) goto werr;
-                    if (fwriteBulk(fp,eleobj) == 0) goto werr;
+                    if (fwriteBulkObject(fp,eleobj) == 0) goto werr;
                 }
                 dictReleaseIterator(di);
+            } else if (o->type == REDIS_HASH) {
+                char cmd[]="*4\r\n$4\r\nHSET\r\n";
+
+                /* Emit the HSETs needed to rebuild the hash */
+                if (o->encoding == REDIS_ENCODING_ZIPMAP) {
+                    unsigned char *p = zipmapRewind(o->ptr);
+                    unsigned char *field, *val;
+                    unsigned int flen, vlen;
+
+                    while((p = zipmapNext(p,&field,&flen,&val,&vlen)) != NULL) {
+                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
+                        if (fwriteBulkObject(fp,key) == 0) goto werr;
+                        if (fwriteBulkString(fp,(char*)field,flen) == -1)
+                            return -1;
+                        if (fwriteBulkString(fp,(char*)val,vlen) == -1)
+                            return -1;
+                    }
+                } else {
+                    dictIterator *di = dictGetIterator(o->ptr);
+                    dictEntry *de;
+
+                    while((de = dictNext(di)) != NULL) {
+                        robj *field = dictGetEntryKey(de);
+                        robj *val = dictGetEntryVal(de);
+
+                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
+                        if (fwriteBulkObject(fp,key) == 0) goto werr;
+                        if (fwriteBulkObject(fp,field) == -1) return -1;
+                        if (fwriteBulkObject(fp,val) == -1) return -1;
+                    }
+                    dictReleaseIterator(di);
+                }
             } else {
-                redisAssert(0 != 0);
+                redisAssert(0);
             }
             /* Save the expire time */
             if (expiretime != -1) {
@@ -7217,7 +7825,7 @@ static int rewriteAppendOnlyFile(char *filename) {
                 /* If this key is already expired skip it */
                 if (expiretime < now) continue;
                 if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
-                if (fwriteBulk(fp,key) == 0) goto werr;
+                if (fwriteBulkObject(fp,key) == 0) goto werr;
                 if (fwriteBulkLong(fp,expiretime) == 0) goto werr;
             }
             if (swapped) decrRefCount(o);
@@ -8262,6 +8870,15 @@ static int waitForSwappedKey(redisClient *c, robj *key) {
     return 1;
 }
 
+/* Preload keys needed for the ZUNION and ZINTER commands. */
+static void zunionInterBlockClientOnSwappedKeys(redisClient *c) {
+    int i, num;
+    num = atoi(c->argv[2]->ptr);
+    for (i = 0; i < num; i++) {
+        waitForSwappedKey(c,c->argv[3+i]);
+    }
+}
+
 /* Is this client attempting to run a command against swapped keys?
  * If so, block it ASAP, load the keys in background, then resume it.
  *
@@ -8275,11 +8892,16 @@ static int waitForSwappedKey(redisClient *c, robj *key) {
 static int blockClientOnSwappedKeys(struct redisCommand *cmd, redisClient *c) {
     int j, last;
 
-    if (cmd->vm_firstkey == 0) return 0;
-    last = cmd->vm_lastkey;
-    if (last < 0) last = c->argc+last;
-    for (j = cmd->vm_firstkey; j <= last; j += cmd->vm_keystep)
-        waitForSwappedKey(c,c->argv[j]);
+    if (cmd->vm_preload_proc != NULL) {
+        cmd->vm_preload_proc(c);
+    } else {
+        if (cmd->vm_firstkey == 0) return 0;
+        last = cmd->vm_lastkey;
+        if (last < 0) last = c->argc+last;
+        for (j = cmd->vm_firstkey; j <= last; j += cmd->vm_keystep)
+            waitForSwappedKey(c,c->argv[j]);
+    }
+
     /* If the client was blocked for at least one key, mark it as blocked. */
     if (listLength(c->io_keys)) {
         c->flags |= REDIS_IO_WAIT;
@@ -8386,11 +9008,20 @@ static void debugCommand(redisClient *c) {
         val = dictGetEntryVal(de);
         if (!server.vm_enabled || (key->storage == REDIS_VM_MEMORY ||
                                    key->storage == REDIS_VM_SWAPPING)) {
+            char *strenc;
+            char buf[128];
+
+            if (val->encoding < (sizeof(strencoding)/sizeof(char*))) {
+                strenc = strencoding[val->encoding];
+            } else {
+                snprintf(buf,64,"unknown encoding %d\n", val->encoding);
+                strenc = buf;
+            }
             addReplySds(c,sdscatprintf(sdsempty(),
                 "+Key at:%p refcount:%d, value at:%p refcount:%d "
-                "encoding:%d serializedlength:%lld\r\n",
+                "encoding:%s serializedlength:%lld\r\n",
                 (void*)key, key->refcount, (void*)val, val->refcount,
-                val->encoding, (long long) rdbSavedObjectLen(val,NULL)));
+                strenc, (long long) rdbSavedObjectLen(val,NULL)));
         } else {
             addReplySds(c,sdscatprintf(sdsempty(),
                 "+Key at:%p refcount:%d, value swapped at: page %llu "