X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/abcb223ec05740c3534b31e3c756ac0d63f8c07e..5a6e8b1daa259141917ccc83cb3851614efac615:/redis.c

diff --git a/redis.c b/redis.c
index fa62c54c..05a623d5 100644
--- a/redis.c
+++ b/redis.c
@@ -27,7 +27,9 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-#define REDIS_VERSION "0.08"
+#define REDIS_VERSION "0.09"
+
+#include "fmacros.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -54,6 +56,7 @@
 #include "dict.h"   /* Hash tables */
 #include "adlist.h" /* Linked lists */
 #include "zmalloc.h" /* total memory usage aware version of malloc/free */
+#include "lzf.h"
 
 /* Error codes */
 #define REDIS_OK                0
@@ -69,6 +72,7 @@
 #define REDIS_CONFIGLINE_MAX    1024
 #define REDIS_OBJFREELIST_MAX   1000000 /* Max number of objects to cache */
 #define REDIS_MAX_SYNC_TIME     60      /* Slave can't take more to sync */
+#define REDIS_EXPIRELOOKUPS_PER_CRON    100 /* try to expire 100 keys/second */
 
 /* Hash table parameters */
 #define REDIS_HT_MINFILL        10      /* Minimal hash table fill 10% */
@@ -85,6 +89,7 @@
 #define REDIS_HASH 3
 
 /* Object types only used for dumping to disk */
+#define REDIS_EXPIRETIME 253
 #define REDIS_SELECTDB 254
 #define REDIS_EOF 255
 
@@ -95,16 +100,26 @@
  * 00|000000 => if the two MSB are 00 the len is the 6 bits of this byte
  * 01|000000 00000000 =>  01, the len is 14 byes, 6 bits + 8 bits of next byte
  * 10|000000 [32 bit integer] => if it's 01, a full 32 bit len will follow
- * 11|000000 reserved for future uses
+ * 11|000000 this means: specially encoded object will follow. The six bits
+ *           number specify the kind of object that follows.
+ *           See the REDIS_RDB_ENC_* defines.
  *
  * Lenghts up to 63 are stored using a single byte, most DB keys, and may
  * values, will fit inside. */
 #define REDIS_RDB_6BITLEN 0
 #define REDIS_RDB_14BITLEN 1
 #define REDIS_RDB_32BITLEN 2
-#define REDIS_RDB_64BITLEN 3
+#define REDIS_RDB_ENCVAL 3
 #define REDIS_RDB_LENERR UINT_MAX
 
+/* When a length of a string object stored on disk has the first two bits
+ * set, the remaining two bits specify a special encoding for the object
+ * accordingly to the following defines: */
+#define REDIS_RDB_ENC_INT8 0        /* 8 bit signed integer */
+#define REDIS_RDB_ENC_INT16 1       /* 16 bit signed integer */
+#define REDIS_RDB_ENC_INT32 2       /* 32 bit signed integer */
+#define REDIS_RDB_ENC_LZF 3         /* string compressed with FASTLZ */
+
 /* Client flags */
 #define REDIS_CLOSE 1       /* This client connection should be closed ASAP */
 #define REDIS_SLAVE 2       /* This client is a slave server */
@@ -141,16 +156,22 @@
 
 /* A redis object, that is a type able to hold a string / list / set */
 typedef struct redisObject {
-    int type;
     void *ptr;
+    int type;
     int refcount;
 } robj;
 
+typedef struct redisDb {
+    dict *dict;
+    dict *expires;
+    int id;
+} redisDb;
+
 /* With multiplexing we need to take per-clinet state.
  * Clients are taken in a liked list. */
 typedef struct redisClient {
     int fd;
-    dict *dict;
+    redisDb *db;
     int dictid;
     sds querybuf;
     robj *argv[REDIS_MAX_ARGS];
@@ -173,7 +194,7 @@ struct saveparam {
 struct redisServer {
     int port;
     int fd;
-    dict **dict;
+    redisDb *db;
     dict *sharingpool;
     unsigned int sharingpoolsize;
     long long dirty;            /* changes to DB from the last save */
@@ -184,7 +205,7 @@ struct redisServer {
     int cronloops;              /* number of times the cron function run */
     list *objfreelist;          /* A list of freed objects to avoid malloc() */
     time_t lastsave;            /* Unix time of last save succeeede */
-    int usedmemory;             /* Used memory in megabytes */
+    size_t usedmemory;             /* Used memory in megabytes */
     /* Fields used only for stats */
     time_t stat_starttime;         /* server start time */
     long long stat_numcommands;    /* number of processed commands */
@@ -264,6 +285,12 @@ static robj *createStringObject(char *ptr, size_t len);
 static void replicationFeedSlaves(list *slaves, struct redisCommand *cmd, int dictid, robj **argv, int argc);
 static int syncWithMaster(void);
 static robj *tryObjectSharing(robj *o);
+static int removeExpire(redisDb *db, robj *key);
+static int expireIfNeeded(redisDb *db, robj *key);
+static int deleteIfVolatile(redisDb *db, robj *key);
+static int deleteKey(redisDb *db, robj *key);
+static time_t getExpire(redisDb *db, robj *key);
+static int setExpire(redisDb *db, robj *key, time_t when);
 
 static void authCommand(redisClient *c);
 static void pingCommand(redisClient *c);
@@ -312,6 +339,7 @@ static void lremCommand(redisClient *c);
 static void infoCommand(redisClient *c);
 static void mgetCommand(redisClient *c);
 static void monitorCommand(redisClient *c);
+static void expireCommand(redisClient *c);
 
 /*================================= Globals ================================= */
 
@@ -366,6 +394,7 @@ static struct redisCommand cmdTable[] = {
     {"sort",sortCommand,-2,REDIS_CMD_INLINE},
     {"info",infoCommand,1,REDIS_CMD_INLINE},
     {"monitor",monitorCommand,1,REDIS_CMD_INLINE},
+    {"expire",expireCommand,3,REDIS_CMD_INLINE},
     {NULL,NULL,0,0}
 };
 
@@ -605,7 +634,7 @@ void closeTimedoutClients(void) {
 }
 
 int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
-    int j, size, used, loops = server.cronloops++;
+    int j, loops = server.cronloops++;
     REDIS_NOTUSED(eventLoop);
     REDIS_NOTUSED(id);
     REDIS_NOTUSED(clientData);
@@ -616,27 +645,30 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
     /* If the percentage of used slots in the HT reaches REDIS_HT_MINFILL
      * we resize the hash table to save memory */
     for (j = 0; j < server.dbnum; j++) {
-        size = dictGetHashTableSize(server.dict[j]);
-        used = dictGetHashTableUsed(server.dict[j]);
+        int size, used, vkeys;
+
+        size = dictSlots(server.db[j].dict);
+        used = dictSize(server.db[j].dict);
+        vkeys = dictSize(server.db[j].expires);
         if (!(loops % 5) && used > 0) {
-            redisLog(REDIS_DEBUG,"DB %d: %d keys in %d slots HT.",j,used,size);
-            // dictPrintStats(server.dict);
+            redisLog(REDIS_DEBUG,"DB %d: %d keys (%d volatile) in %d slots HT.",j,used,vkeys,size);
+            /* dictPrintStats(server.dict); */
         }
         if (size && used && size > REDIS_HT_MINSLOTS &&
             (used*100/size < REDIS_HT_MINFILL)) {
             redisLog(REDIS_NOTICE,"The hash table %d is too sparse, resize it...",j);
-            dictResize(server.dict[j]);
+            dictResize(server.db[j].dict);
             redisLog(REDIS_NOTICE,"Hash table %d resized.",j);
         }
     }
 
     /* Show information about connected clients */
     if (!(loops % 5)) {
-        redisLog(REDIS_DEBUG,"%d clients connected (%d slaves), %d bytes in use",
+        redisLog(REDIS_DEBUG,"%d clients connected (%d slaves), %zu bytes in use",
             listLength(server.clients)-listLength(server.slaves),
             listLength(server.slaves),
             server.usedmemory,
-            dictGetHashTableUsed(server.sharingpool));
+            dictSize(server.sharingpool));
     }
 
     /* Close connections of timedout clients */
@@ -675,6 +707,30 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
             }
          }
     }
+
+    /* Try to expire a few timed out keys */
+    for (j = 0; j < server.dbnum; j++) {
+        redisDb *db = server.db+j;
+        int num = dictSize(db->expires);
+
+        if (num) {
+            time_t now = time(NULL);
+
+            if (num > REDIS_EXPIRELOOKUPS_PER_CRON)
+                num = REDIS_EXPIRELOOKUPS_PER_CRON;
+            while (num--) {
+                dictEntry *de;
+                time_t t;
+
+                if ((de = dictGetRandomKey(db->expires)) == NULL) break;
+                t = (time_t) dictGetEntryVal(de);
+                if (now > t) {
+                    deleteKey(db,dictGetEntryKey(de));
+                }
+            }
+        }
+    }
+
     /* Check if we should connect to a MASTER */
     if (server.replstate == REDIS_REPL_CONNECT) {
         redisLog(REDIS_NOTICE,"Connecting to MASTER...");
@@ -775,18 +831,21 @@ static void initServer() {
     server.objfreelist = listCreate();
     createSharedObjects();
     server.el = aeCreateEventLoop();
-    server.dict = zmalloc(sizeof(dict*)*server.dbnum);
+    server.db = zmalloc(sizeof(redisDb)*server.dbnum);
     server.sharingpool = dictCreate(&setDictType,NULL);
     server.sharingpoolsize = 1024;
-    if (!server.dict || !server.clients || !server.slaves || !server.monitors || !server.el || !server.objfreelist)
+    if (!server.db || !server.clients || !server.slaves || !server.monitors || !server.el || !server.objfreelist)
         oom("server initialization"); /* Fatal OOM */
     server.fd = anetTcpServer(server.neterr, server.port, server.bindaddr);
     if (server.fd == -1) {
         redisLog(REDIS_WARNING, "Opening TCP port: %s", server.neterr);
         exit(1);
     }
-    for (j = 0; j < server.dbnum; j++)
-        server.dict[j] = dictCreate(&hashDictType,NULL);
+    for (j = 0; j < server.dbnum; j++) {
+        server.db[j].dict = dictCreate(&hashDictType,NULL);
+        server.db[j].expires = dictCreate(&setDictType,NULL);
+        server.db[j].id = j;
+    }
     server.cronloops = 0;
     server.bgsaveinprogress = 0;
     server.lastsave = time(NULL);
@@ -802,8 +861,10 @@ static void initServer() {
 static void emptyDb() {
     int j;
 
-    for (j = 0; j < server.dbnum; j++)
-        dictEmpty(server.dict[j]);
+    for (j = 0; j < server.dbnum; j++) {
+        dictEmpty(server.db[j].dict);
+        dictEmpty(server.db[j].expires);
+    }
 }
 
 /* I agree, this is a very rudimental way to load a configuration...
@@ -1027,7 +1088,7 @@ static void sendReplyToClient(aeEventLoop *el, int fd, void *privdata, int mask)
         if (c->flags & REDIS_MASTER) {
             nwritten = objlen - c->sentlen;
         } else {
-            nwritten = write(fd, o->ptr+c->sentlen, objlen - c->sentlen);
+            nwritten = write(fd, ((char*)o->ptr)+c->sentlen, objlen - c->sentlen);
             if (nwritten <= 0) break;
         }
         c->sentlen += nwritten;
@@ -1099,10 +1160,6 @@ static int processCommand(redisClient *c) {
         addReplySds(c,sdsnew("-ERR wrong number of arguments\r\n"));
         resetClient(c);
         return 1;
-    } else if (server.requirepass && !c->authenticated && strcmp(c->argv[0]->ptr,"auth")) {
-        addReplySds(c,sdsnew("-ERR operation not permitted\r\n"));
-        resetClient(c);
-        return 1;
     } else if (cmd->flags & REDIS_CMD_BULK && c->bulklen == -1) {
         int bulklen = atoi(c->argv[c->argc-1]->ptr);
 
@@ -1131,13 +1188,20 @@ static int processCommand(redisClient *c) {
         for(j = 1; j < c->argc; j++)
             c->argv[j] = tryObjectSharing(c->argv[j]);
     }
+    /* Check if the user is authenticated */
+    if (server.requirepass && !c->authenticated && cmd->proc != authCommand) {
+        addReplySds(c,sdsnew("-ERR operation not permitted\r\n"));
+        resetClient(c);
+        return 1;
+    }
+
     /* Exec the command */
     dirty = server.dirty;
     cmd->proc(c);
     if (server.dirty-dirty != 0 && listLength(server.slaves))
-        replicationFeedSlaves(server.slaves,cmd,c->dictid,c->argv,c->argc);
+        replicationFeedSlaves(server.slaves,cmd,c->db->id,c->argv,c->argc);
     if (listLength(server.monitors))
-        replicationFeedSlaves(server.monitors,cmd,c->dictid,c->argv,c->argc);
+        replicationFeedSlaves(server.monitors,cmd,c->db->id,c->argv,c->argc);
     server.stat_numcommands++;
 
     /* Prepare the client for the next command */
@@ -1295,8 +1359,7 @@ again:
 static int selectDb(redisClient *c, int id) {
     if (id < 0 || id >= server.dbnum)
         return REDIS_ERR;
-    c->dict = server.dict[id];
-    c->dictid = id;
+    c->db = &server.db[id];
     return REDIS_OK;
 }
 
@@ -1398,14 +1461,6 @@ static robj *createSetObject(void) {
     return createObject(REDIS_SET,d);
 }
 
-#if 0
-static robj *createHashObject(void) {
-    dict *d = dictCreate(&hashDictType,NULL);
-    if (!d) oom("dictCreate");
-    return createObject(REDIS_SET,d);
-}
-#endif
-
 static void freeStringObject(robj *o) {
     sdsfree(o->ptr);
 }
@@ -1424,10 +1479,19 @@ static void freeHashObject(robj *o) {
 
 static void incrRefCount(robj *o) {
     o->refcount++;
+#ifdef DEBUG_REFCOUNT
+    if (o->type == REDIS_STRING)
+        printf("Increment '%s'(%p), now is: %d\n",o->ptr,o,o->refcount);
+#endif
 }
 
 static void decrRefCount(void *obj) {
     robj *o = obj;
+
+#ifdef DEBUG_REFCOUNT
+    if (o->type == REDIS_STRING)
+        printf("Decrement '%s'(%p), now is: %d\n",o->ptr,o,o->refcount-1);
+#endif
     if (--(o->refcount) == 0) {
         switch(o->type) {
         case REDIS_STRING: freeStringObject(o); break;
@@ -1447,7 +1511,7 @@ static robj *tryObjectSharing(robj *o) {
     struct dictEntry *de;
     unsigned long c;
 
-    if (server.shareobjects == 0) return o;
+    if (o == NULL || server.shareobjects == 0) return o;
 
     assert(o->type == REDIS_STRING);
     de = dictFind(server.sharingpool,o);
@@ -1464,7 +1528,7 @@ static robj *tryObjectSharing(robj *o) {
          * shared we increment its count, everytime there is a miss we
          * recrement the counter of a random object. If this object reaches
          * zero we remove the object and put the current object instead. */
-        if (dictGetHashTableUsed(server.sharingpool) >=
+        if (dictSize(server.sharingpool) >=
                 server.sharingpoolsize) {
             de = dictGetRandomKey(server.sharingpool);
             assert(de != NULL);
@@ -1487,6 +1551,36 @@ static robj *tryObjectSharing(robj *o) {
     }
 }
 
+static robj *lookupKey(redisDb *db, robj *key) {
+    dictEntry *de = dictFind(db->dict,key);
+    return de ? dictGetEntryVal(de) : NULL;
+}
+
+static robj *lookupKeyRead(redisDb *db, robj *key) {
+    expireIfNeeded(db,key);
+    return lookupKey(db,key);
+}
+
+static robj *lookupKeyWrite(redisDb *db, robj *key) {
+    deleteIfVolatile(db,key);
+    return lookupKey(db,key);
+}
+
+static int deleteKey(redisDb *db, robj *key) {
+    int retval;
+
+    /* We need to protect key from destruction: after the first dictDelete()
+     * it may happen that 'key' is no longer valid if we don't increment
+     * it's count. This may happen when we get the object reference directly
+     * from the hash table with dictRandomKey() or dict iterators */
+    incrRefCount(key);
+    if (dictSize(db->expires)) dictDelete(db->expires,key);
+    retval = dictDelete(db->dict,key);
+    decrRefCount(key);
+
+    return retval == DICT_OK;
+}
+
 /*============================ DB saving/loading ============================ */
 
 static int rdbSaveType(FILE *fp, unsigned char type) {
@@ -1494,6 +1588,13 @@ static int rdbSaveType(FILE *fp, unsigned char type) {
     return 0;
 }
 
+static int rdbSaveTime(FILE *fp, time_t t) {
+    int32_t t32 = (int32_t) t;
+    if (fwrite(&t32,4,1,fp) == 0) return -1;
+    return 0;
+}
+
+/* check rdbLoadLen() comments for more info */
 static int rdbSaveLen(FILE *fp, uint32_t len) {
     unsigned char buf[2];
 
@@ -1505,7 +1606,7 @@ static int rdbSaveLen(FILE *fp, uint32_t len) {
         /* Save a 14 bit len */
         buf[0] = ((len>>8)&0xFF)|(REDIS_RDB_14BITLEN<<6);
         buf[1] = len&0xFF;
-        if (fwrite(buf,4,1,fp) == 0) return -1;
+        if (fwrite(buf,2,1,fp) == 0) return -1;
     } else {
         /* Save a 32 bit len */
         buf[0] = (REDIS_RDB_32BITLEN<<6);
@@ -1516,9 +1617,99 @@ static int rdbSaveLen(FILE *fp, uint32_t len) {
     return 0;
 }
 
+/* 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 */
+int rdbTryIntegerEncoding(sds s, unsigned char *enc) {
+    long long value;
+    char *endptr, buf[32];
+
+    /* Check if it's possible to encode this value as a number */
+    value = strtoll(s, &endptr, 10);
+    if (endptr[0] != '\0') return 0;
+    snprintf(buf,32,"%lld",value);
+
+    /* 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;
+
+    /* Finally check if it fits in our ranges */
+    if (value >= -(1<<7) && value <= (1<<7)-1) {
+        enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT8;
+        enc[1] = value&0xFF;
+        return 2;
+    } else if (value >= -(1<<15) && value <= (1<<15)-1) {
+        enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT16;
+        enc[1] = value&0xFF;
+        enc[2] = (value>>8)&0xFF;
+        return 3;
+    } else if (value >= -((long long)1<<31) && value <= ((long long)1<<31)-1) {
+        enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT32;
+        enc[1] = value&0xFF;
+        enc[2] = (value>>8)&0xFF;
+        enc[3] = (value>>16)&0xFF;
+        enc[4] = (value>>24)&0xFF;
+        return 5;
+    } else {
+        return 0;
+    }
+}
+
+static int rdbSaveLzfStringObject(FILE *fp, robj *obj) {
+    unsigned int 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 ((out = zmalloc(outlen)) == NULL) return 0;
+    comprlen = lzf_compress(obj->ptr, sdslen(obj->ptr), out, outlen);
+    if (comprlen == 0) {
+        zfree(out);
+        return 0;
+    }
+    /* Data compressed! Let's save it on disk */
+    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 (fwrite(out,comprlen,1,fp) == 0) goto writeerr;
+    zfree(out);
+    return comprlen;
+
+writeerr:
+    zfree(out);
+    return -1;
+}
+
+/* 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 rdbSaveStringObject(FILE *fp, robj *obj) {
     size_t len = sdslen(obj->ptr);
+    int enclen;
+
+    /* Try integer encoding */
+    if (len <= 11) {
+        unsigned char buf[5];
+        if ((enclen = rdbTryIntegerEncoding(obj->ptr,buf)) > 0) {
+            if (fwrite(buf,enclen,1,fp) == 0) return -1;
+            return 0;
+        }
+    }
+
+    /* Try LZF compression - under 20 bytes it's unable to compress even
+     * aaaaaaaaaaaaaaaaaa so skip it */
+    if (len > 20) {
+        int retval;
+
+        retval = rdbSaveLzfStringObject(fp,obj);
+        if (retval == -1) return -1;
+        if (retval > 0) return 0;
+        /* retval == 0 means data can't be compressed, save the old way */
+    }
 
+    /* Store verbatim */
     if (rdbSaveLen(fp,len) == -1) return -1;
     if (len && fwrite(obj->ptr,len,1,fp) == 0) return -1;
     return 0;
@@ -1531,6 +1722,7 @@ static int rdbSave(char *filename) {
     FILE *fp;
     char tmpfile[256];
     int j;
+    time_t now = time(NULL);
 
     snprintf(tmpfile,256,"temp-%d.%ld.rdb",(int)time(NULL),(long int)random());
     fp = fopen(tmpfile,"w");
@@ -1540,8 +1732,9 @@ static int rdbSave(char *filename) {
     }
     if (fwrite("REDIS0001",9,1,fp) == 0) goto werr;
     for (j = 0; j < server.dbnum; j++) {
-        dict *d = server.dict[j];
-        if (dictGetHashTableUsed(d) == 0) continue;
+        redisDb *db = server.db+j;
+        dict *d = db->dict;
+        if (dictSize(d) == 0) continue;
         di = dictGetIterator(d);
         if (!di) {
             fclose(fp);
@@ -1556,7 +1749,16 @@ static int rdbSave(char *filename) {
         while((de = dictNext(di)) != NULL) {
             robj *key = dictGetEntryKey(de);
             robj *o = dictGetEntryVal(de);
-
+            time_t expiretime = getExpire(db,key);
+
+            /* Save the expire time */
+            if (expiretime != -1) {
+                /* If this key is already expired skip it */
+                if (expiretime < now) continue;
+                if (rdbSaveType(fp,REDIS_EXPIRETIME) == -1) goto werr;
+                if (rdbSaveTime(fp,expiretime) == -1) goto werr;
+            }
+            /* Save the key and associated value */
             if (rdbSaveType(fp,o->type) == -1) goto werr;
             if (rdbSaveStringObject(fp,key) == -1) goto werr;
             if (o->type == REDIS_STRING) {
@@ -1581,7 +1783,7 @@ static int rdbSave(char *filename) {
                 dictEntry *de;
 
                 if (!set) oom("dictGetIteraotr");
-                if (rdbSaveLen(fp,dictGetHashTableUsed(set)) == -1) goto werr;
+                if (rdbSaveLen(fp,dictSize(set)) == -1) goto werr;
                 while((de = dictNext(di)) != NULL) {
                     robj *eleobj = dictGetEntryKey(de);
 
@@ -1649,19 +1851,38 @@ static int rdbLoadType(FILE *fp) {
     return type;
 }
 
-static uint32_t rdbLoadLen(FILE *fp, int rdbver) {
+static time_t rdbLoadTime(FILE *fp) {
+    int32_t t32;
+    if (fread(&t32,4,1,fp) == 0) return -1;
+    return (time_t) t32;
+}
+
+/* Load an encoded length from the DB, see the REDIS_RDB_* defines on the top
+ * of this file for a description of how this are stored on disk.
+ *
+ * isencoded is set to 1 if the readed length is not actually a length but
+ * an "encoding type", check the above comments for more info */
+static uint32_t rdbLoadLen(FILE *fp, int rdbver, int *isencoded) {
     unsigned char buf[2];
     uint32_t len;
 
+    if (isencoded) *isencoded = 0;
     if (rdbver == 0) {
         if (fread(&len,4,1,fp) == 0) return REDIS_RDB_LENERR;
         return ntohl(len);
     } else {
+        int type;
+
         if (fread(buf,1,1,fp) == 0) return REDIS_RDB_LENERR;
-        if ((buf[0]&0xC0) == REDIS_RDB_6BITLEN) {
+        type = (buf[0]&0xC0)>>6;
+        if (type == REDIS_RDB_6BITLEN) {
             /* Read a 6 bit len */
-            return buf[0];
-        } else if ((buf[0]&0xC0) == REDIS_RDB_14BITLEN) {
+            return buf[0]&0x3F;
+        } else if (type == REDIS_RDB_ENCVAL) {
+            /* Read a 6 bit len encoding type */
+            if (isencoded) *isencoded = 1;
+            return buf[0]&0x3F;
+        } else if (type == REDIS_RDB_14BITLEN) {
             /* Read a 14 bit len */
             if (fread(buf+1,1,1,fp) == 0) return REDIS_RDB_LENERR;
             return ((buf[0]&0x3F)<<8)|buf[1];
@@ -1673,10 +1894,67 @@ static uint32_t rdbLoadLen(FILE *fp, int rdbver) {
     }
 }
 
-static robj *rdbLoadStringObject(FILE*fp,int rdbver) {
-    uint32_t len = rdbLoadLen(fp,rdbver);
+static robj *rdbLoadIntegerObject(FILE *fp, int enctype) {
+    unsigned char enc[4];
+    long long val;
+
+    if (enctype == REDIS_RDB_ENC_INT8) {
+        if (fread(enc,1,1,fp) == 0) return NULL;
+        val = (signed char)enc[0];
+    } else if (enctype == REDIS_RDB_ENC_INT16) {
+        uint16_t v;
+        if (fread(enc,2,1,fp) == 0) return NULL;
+        v = enc[0]|(enc[1]<<8);
+        val = (int16_t)v;
+    } else if (enctype == REDIS_RDB_ENC_INT32) {
+        uint32_t v;
+        if (fread(enc,4,1,fp) == 0) return NULL;
+        v = enc[0]|(enc[1]<<8)|(enc[2]<<16)|(enc[3]<<24);
+        val = (int32_t)v;
+    } else {
+        val = 0; /* anti-warning */
+        assert(0!=0);
+    }
+    return createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",val));
+}
+
+static robj *rdbLoadLzfStringObject(FILE*fp, int rdbver) {
+    unsigned int len, clen;
+    unsigned char *c = NULL;
+    sds val = NULL;
+
+    if ((clen = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR) return NULL;
+    if ((len = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR) return NULL;
+    if ((c = zmalloc(clen)) == NULL) goto err;
+    if ((val = sdsnewlen(NULL,len)) == NULL) goto err;
+    if (fread(c,clen,1,fp) == 0) goto err;
+    if (lzf_decompress(c,clen,val,len) == 0) goto err;
+    return createObject(REDIS_STRING,val);
+err:
+    zfree(c);
+    sdsfree(val);
+    return NULL;
+}
+
+static robj *rdbLoadStringObject(FILE*fp, int rdbver) {
+    int isencoded;
+    uint32_t len;
     sds val;
 
+    len = rdbLoadLen(fp,rdbver,&isencoded);
+    if (isencoded) {
+        switch(len) {
+        case REDIS_RDB_ENC_INT8:
+        case REDIS_RDB_ENC_INT16:
+        case REDIS_RDB_ENC_INT32:
+            return tryObjectSharing(rdbLoadIntegerObject(fp,len));
+        case REDIS_RDB_ENC_LZF:
+            return tryObjectSharing(rdbLoadLzfStringObject(fp,rdbver));
+        default:
+            assert(0!=0);
+        }
+    }
+
     if (len == REDIS_RDB_LENERR) return NULL;
     val = sdsnewlen(NULL,len);
     if (len && fread(val,len,1,fp) == 0) {
@@ -1690,11 +1968,12 @@ static int rdbLoad(char *filename) {
     FILE *fp;
     robj *keyobj = NULL;
     uint32_t dbid;
-    int type;
-    int retval;
-    dict *d = server.dict[0];
+    int type, retval, rdbver;
+    dict *d = server.db[0].dict;
+    redisDb *db = server.db+0;
     char buf[1024];
-    int rdbver;
+    time_t expiretime = -1, now = time(NULL);
+
     fp = fopen(filename,"r");
     if (!fp) return REDIS_ERR;
     if (fread(buf,9,1,fp) == 0) goto eoferr;
@@ -1715,15 +1994,22 @@ static int rdbLoad(char *filename) {
 
         /* Read type. */
         if ((type = rdbLoadType(fp)) == -1) goto eoferr;
+        if (type == REDIS_EXPIRETIME) {
+            if ((expiretime = rdbLoadTime(fp)) == -1) goto eoferr;
+            /* We read the time so we need to read the object type again */
+            if ((type = rdbLoadType(fp)) == -1) goto eoferr;
+        }
         if (type == REDIS_EOF) break;
         /* Handle SELECT DB opcode as a special case */
         if (type == REDIS_SELECTDB) {
-            if ((dbid = rdbLoadLen(fp,rdbver)) == REDIS_RDB_LENERR) goto eoferr;
+            if ((dbid = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR)
+                goto eoferr;
             if (dbid >= (unsigned)server.dbnum) {
                 redisLog(REDIS_WARNING,"FATAL: Data file was created with a Redis server configured to handle more than %d databases. Exiting\n", server.dbnum);
                 exit(1);
             }
-            d = server.dict[dbid];
+            db = server.db+dbid;
+            d = db->dict;
             continue;
         }
         /* Read key */
@@ -1736,7 +2022,7 @@ static int rdbLoad(char *filename) {
             /* Read list/set value */
             uint32_t listlen;
 
-            if ((listlen = rdbLoadLen(fp,rdbver)) == REDIS_RDB_LENERR)
+            if ((listlen = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR)
                 goto eoferr;
             o = (type == REDIS_LIST) ? createListObject() : createSetObject();
             /* Load every single element of the list/set */
@@ -1761,14 +2047,21 @@ static int rdbLoad(char *filename) {
             redisLog(REDIS_WARNING,"Loading DB, duplicated key (%s) found! Unrecoverable error, exiting now.", keyobj->ptr);
             exit(1);
         }
+        /* Set the expire time if needed */
+        if (expiretime != -1) {
+            setExpire(db,keyobj,expiretime);
+            /* Delete this key if already expired */
+            if (expiretime < now) deleteKey(db,keyobj);
+            expiretime = -1;
+        }
         keyobj = o = NULL;
     }
     fclose(fp);
     return REDIS_OK;
 
 eoferr: /* unexpected end of file is handled here with a fatal exit */
-    decrRefCount(keyobj);
-    redisLog(REDIS_WARNING,"Short read loading DB. Unrecoverable error, exiting now.");
+    if (keyobj) decrRefCount(keyobj);
+    redisLog(REDIS_WARNING,"Short read or OOM loading DB. Unrecoverable error, exiting now.");
     exit(1);
     return REDIS_ERR; /* Just to avoid warning */
 }
@@ -1776,7 +2069,7 @@ eoferr: /* unexpected end of file is handled here with a fatal exit */
 /*================================== Commands =============================== */
 
 static void authCommand(redisClient *c) {
-    if (!strcmp(c->argv[1]->ptr, server.requirepass)) {
+    if (!server.requirepass || !strcmp(c->argv[1]->ptr, server.requirepass)) {
       c->authenticated = 1;
       addReply(c,shared.ok);
     } else {
@@ -1801,10 +2094,10 @@ static void echoCommand(redisClient *c) {
 static void setGenericCommand(redisClient *c, int nx) {
     int retval;
 
-    retval = dictAdd(c->dict,c->argv[1],c->argv[2]);
+    retval = dictAdd(c->db->dict,c->argv[1],c->argv[2]);
     if (retval == DICT_ERR) {
         if (!nx) {
-            dictReplace(c->dict,c->argv[1],c->argv[2]);
+            dictReplace(c->db->dict,c->argv[1],c->argv[2]);
             incrRefCount(c->argv[2]);
         } else {
             addReply(c,shared.czero);
@@ -1815,26 +2108,24 @@ static void setGenericCommand(redisClient *c, int nx) {
         incrRefCount(c->argv[2]);
     }
     server.dirty++;
+    removeExpire(c->db,c->argv[1]);
     addReply(c, nx ? shared.cone : shared.ok);
 }
 
 static void setCommand(redisClient *c) {
-    return setGenericCommand(c,0);
+    setGenericCommand(c,0);
 }
 
 static void setnxCommand(redisClient *c) {
-    return setGenericCommand(c,1);
+    setGenericCommand(c,1);
 }
 
 static void getCommand(redisClient *c) {
-    dictEntry *de;
-    
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    robj *o = lookupKeyRead(c->db,c->argv[1]);
+
+    if (o == NULL) {
         addReply(c,shared.nullbulk);
     } else {
-        robj *o = dictGetEntryVal(de);
-        
         if (o->type != REDIS_STRING) {
             addReply(c,shared.wrongtypeerr);
         } else {
@@ -1846,17 +2137,14 @@ static void getCommand(redisClient *c) {
 }
 
 static void mgetCommand(redisClient *c) {
-    dictEntry *de;
     int j;
   
     addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",c->argc-1));
     for (j = 1; j < c->argc; j++) {
-        de = dictFind(c->dict,c->argv[j]);
-        if (de == NULL) {
+        robj *o = lookupKeyRead(c->db,c->argv[j]);
+        if (o == NULL) {
             addReply(c,shared.nullbulk);
         } else {
-            robj *o = dictGetEntryVal(de);
-            
             if (o->type != REDIS_STRING) {
                 addReply(c,shared.nullbulk);
             } else {
@@ -1869,17 +2157,14 @@ static void mgetCommand(redisClient *c) {
 }
 
 static void incrDecrCommand(redisClient *c, int incr) {
-    dictEntry *de;
     long long value;
     int retval;
     robj *o;
     
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    o = lookupKeyWrite(c->db,c->argv[1]);
+    if (o == NULL) {
         value = 0;
     } else {
-        robj *o = dictGetEntryVal(de);
-        
         if (o->type != REDIS_STRING) {
             value = 0;
         } else {
@@ -1891,9 +2176,10 @@ static void incrDecrCommand(redisClient *c, int incr) {
 
     value += incr;
     o = createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",value));
-    retval = dictAdd(c->dict,c->argv[1],o);
+    retval = dictAdd(c->db->dict,c->argv[1],o);
     if (retval == DICT_ERR) {
-        dictReplace(c->dict,c->argv[1],o);
+        dictReplace(c->db->dict,c->argv[1],o);
+        removeExpire(c->db,c->argv[1]);
     } else {
         incrRefCount(c->argv[1]);
     }
@@ -1904,27 +2190,27 @@ static void incrDecrCommand(redisClient *c, int incr) {
 }
 
 static void incrCommand(redisClient *c) {
-    return incrDecrCommand(c,1);
+    incrDecrCommand(c,1);
 }
 
 static void decrCommand(redisClient *c) {
-    return incrDecrCommand(c,-1);
+    incrDecrCommand(c,-1);
 }
 
 static void incrbyCommand(redisClient *c) {
     int incr = atoi(c->argv[2]->ptr);
-    return incrDecrCommand(c,incr);
+    incrDecrCommand(c,incr);
 }
 
 static void decrbyCommand(redisClient *c) {
     int incr = atoi(c->argv[2]->ptr);
-    return incrDecrCommand(c,-incr);
+    incrDecrCommand(c,-incr);
 }
 
 /* ========================= Type agnostic commands ========================= */
 
 static void delCommand(redisClient *c) {
-    if (dictDelete(c->dict,c->argv[1]) == DICT_OK) {
+    if (deleteKey(c->db,c->argv[1])) {
         server.dirty++;
         addReply(c,shared.cone);
     } else {
@@ -1933,20 +2219,14 @@ static void delCommand(redisClient *c) {
 }
 
 static void existsCommand(redisClient *c) {
-    dictEntry *de;
-    
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL)
-        addReply(c,shared.czero);
-    else
-        addReply(c,shared.cone);
+    addReply(c,lookupKeyRead(c->db,c->argv[1]) ? shared.cone : shared.czero);
 }
 
 static void selectCommand(redisClient *c) {
     int id = atoi(c->argv[1]->ptr);
     
     if (selectDb(c,id) == REDIS_ERR) {
-        addReplySds(c,"-ERR invalid DB index\r\n");
+        addReplySds(c,sdsnew("-ERR invalid DB index\r\n"));
     } else {
         addReply(c,shared.ok);
     }
@@ -1954,9 +2234,13 @@ static void selectCommand(redisClient *c) {
 
 static void randomkeyCommand(redisClient *c) {
     dictEntry *de;
-    
-    de = dictGetRandomKey(c->dict);
+   
+    while(1) {
+        de = dictGetRandomKey(c->db->dict);
+        if (!de || expireIfNeeded(c->db,dictGetEntryKey(de)) == 0) break;
+    }
     if (de == NULL) {
+        addReply(c,shared.plus);
         addReply(c,shared.crlf);
     } else {
         addReply(c,shared.plus);
@@ -1973,20 +2257,23 @@ static void keysCommand(redisClient *c) {
     int numkeys = 0, keyslen = 0;
     robj *lenobj = createObject(REDIS_STRING,NULL);
 
-    di = dictGetIterator(c->dict);
+    di = dictGetIterator(c->db->dict);
     if (!di) oom("dictGetIterator");
     addReply(c,lenobj);
     decrRefCount(lenobj);
     while((de = dictNext(di)) != NULL) {
         robj *keyobj = dictGetEntryKey(de);
+
         sds key = keyobj->ptr;
         if ((pattern[0] == '*' && pattern[1] == '\0') ||
             stringmatchlen(pattern,plen,key,sdslen(key),0)) {
-            if (numkeys != 0)
-                addReply(c,shared.space);
-            addReply(c,keyobj);
-            numkeys++;
-            keyslen += sdslen(key);
+            if (expireIfNeeded(c->db,keyobj) == 0) {
+                if (numkeys != 0)
+                    addReply(c,shared.space);
+                addReply(c,keyobj);
+                numkeys++;
+                keyslen += sdslen(key);
+            }
         }
     }
     dictReleaseIterator(di);
@@ -1996,7 +2283,7 @@ static void keysCommand(redisClient *c) {
 
 static void dbsizeCommand(redisClient *c) {
     addReplySds(c,
-        sdscatprintf(sdsempty(),":%lu\r\n",dictGetHashTableUsed(c->dict)));
+        sdscatprintf(sdsempty(),":%lu\r\n",dictSize(c->db->dict)));
 }
 
 static void lastsaveCommand(redisClient *c) {
@@ -2005,15 +2292,13 @@ static void lastsaveCommand(redisClient *c) {
 }
 
 static void typeCommand(redisClient *c) {
-    dictEntry *de;
+    robj *o;
     char *type;
-    
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+
+    o = lookupKeyRead(c->db,c->argv[1]);
+    if (o == NULL) {
         type = "+none";
     } else {
-        robj *o = dictGetEntryVal(de);
-        
         switch(o->type) {
         case REDIS_STRING: type = "+string"; break;
         case REDIS_LIST: type = "+list"; break;
@@ -2026,6 +2311,10 @@ static void typeCommand(redisClient *c) {
 }
 
 static void saveCommand(redisClient *c) {
+    if (server.bgsaveinprogress) {
+        addReplySds(c,sdsnew("-ERR background save in progress\r\n"));
+        return;
+    }
     if (rdbSave(server.dbfilename) == REDIS_OK) {
         addReply(c,shared.ok);
     } else {
@@ -2060,7 +2349,6 @@ static void shutdownCommand(redisClient *c) {
 }
 
 static void renameGenericCommand(redisClient *c, int nx) {
-    dictEntry *de;
     robj *o;
 
     /* To use the same key as src and dst is probably an error */
@@ -2069,24 +2357,24 @@ static void renameGenericCommand(redisClient *c, int nx) {
         return;
     }
 
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    o = lookupKeyWrite(c->db,c->argv[1]);
+    if (o == NULL) {
         addReply(c,shared.nokeyerr);
         return;
     }
-    o = dictGetEntryVal(de);
     incrRefCount(o);
-    if (dictAdd(c->dict,c->argv[2],o) == DICT_ERR) {
+    deleteIfVolatile(c->db,c->argv[2]);
+    if (dictAdd(c->db->dict,c->argv[2],o) == DICT_ERR) {
         if (nx) {
             decrRefCount(o);
             addReply(c,shared.czero);
             return;
         }
-        dictReplace(c->dict,c->argv[2],o);
+        dictReplace(c->db->dict,c->argv[2],o);
     } else {
         incrRefCount(c->argv[2]);
     }
-    dictDelete(c->dict,c->argv[1]);
+    deleteKey(c->db,c->argv[1]);
     server.dirty++;
     addReply(c,nx ? shared.cone : shared.ok);
 }
@@ -2100,21 +2388,19 @@ static void renamenxCommand(redisClient *c) {
 }
 
 static void moveCommand(redisClient *c) {
-    dictEntry *de;
-    robj *o, *key;
-    dict *src, *dst;
+    robj *o;
+    redisDb *src, *dst;
     int srcid;
 
     /* Obtain source and target DB pointers */
-    src = c->dict;
-    srcid = c->dictid;
+    src = c->db;
+    srcid = c->db->id;
     if (selectDb(c,atoi(c->argv[2]->ptr)) == REDIS_ERR) {
         addReply(c,shared.outofrangeerr);
         return;
     }
-    dst = c->dict;
-    c->dict = src;
-    c->dictid = srcid;
+    dst = c->db;
+    selectDb(c,srcid); /* Back to the source DB */
 
     /* If the user is moving using as target the same
      * DB as the source DB it is probably an error. */
@@ -2124,24 +2410,23 @@ static void moveCommand(redisClient *c) {
     }
 
     /* Check if the element exists and get a reference */
-    de = dictFind(c->dict,c->argv[1]);
-    if (!de) {
+    o = lookupKeyWrite(c->db,c->argv[1]);
+    if (!o) {
         addReply(c,shared.czero);
         return;
     }
 
     /* Try to add the element to the target DB */
-    key = dictGetEntryKey(de);
-    o = dictGetEntryVal(de);
-    if (dictAdd(dst,key,o) == DICT_ERR) {
+    deleteIfVolatile(dst,c->argv[1]);
+    if (dictAdd(dst->dict,c->argv[1],o) == DICT_ERR) {
         addReply(c,shared.czero);
         return;
     }
-    incrRefCount(key);
+    incrRefCount(c->argv[1]);
     incrRefCount(o);
 
     /* OK! key moved, free the entry in the source DB */
-    dictDelete(src,c->argv[1]);
+    deleteKey(src,c->argv[1]);
     server.dirty++;
     addReply(c,shared.cone);
 }
@@ -2149,11 +2434,10 @@ static void moveCommand(redisClient *c) {
 /* =================================== Lists ================================ */
 static void pushGenericCommand(redisClient *c, int where) {
     robj *lobj;
-    dictEntry *de;
     list *list;
-    
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+
+    lobj = lookupKeyWrite(c->db,c->argv[1]);
+    if (lobj == NULL) {
         lobj = createListObject();
         list = lobj->ptr;
         if (where == REDIS_HEAD) {
@@ -2161,11 +2445,10 @@ static void pushGenericCommand(redisClient *c, int where) {
         } else {
             if (!listAddNodeTail(list,c->argv[2])) oom("listAddNodeTail");
         }
-        dictAdd(c->dict,c->argv[1],lobj);
+        dictAdd(c->db->dict,c->argv[1],lobj);
         incrRefCount(c->argv[1]);
         incrRefCount(c->argv[2]);
     } else {
-        lobj = dictGetEntryVal(de);
         if (lobj->type != REDIS_LIST) {
             addReply(c,shared.wrongtypeerr);
             return;
@@ -2191,15 +2474,14 @@ static void rpushCommand(redisClient *c) {
 }
 
 static void llenCommand(redisClient *c) {
-    dictEntry *de;
+    robj *o;
     list *l;
     
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    o = lookupKeyRead(c->db,c->argv[1]);
+    if (o == NULL) {
         addReply(c,shared.czero);
         return;
     } else {
-        robj *o = dictGetEntryVal(de);
         if (o->type != REDIS_LIST) {
             addReply(c,shared.wrongtypeerr);
         } else {
@@ -2210,15 +2492,13 @@ static void llenCommand(redisClient *c) {
 }
 
 static void lindexCommand(redisClient *c) {
-    dictEntry *de;
+    robj *o;
     int index = atoi(c->argv[2]->ptr);
     
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    o = lookupKeyRead(c->db,c->argv[1]);
+    if (o == NULL) {
         addReply(c,shared.nullbulk);
     } else {
-        robj *o = dictGetEntryVal(de);
-        
         if (o->type != REDIS_LIST) {
             addReply(c,shared.wrongtypeerr);
         } else {
@@ -2239,15 +2519,13 @@ static void lindexCommand(redisClient *c) {
 }
 
 static void lsetCommand(redisClient *c) {
-    dictEntry *de;
+    robj *o;
     int index = atoi(c->argv[2]->ptr);
     
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    o = lookupKeyWrite(c->db,c->argv[1]);
+    if (o == NULL) {
         addReply(c,shared.nokeyerr);
     } else {
-        robj *o = dictGetEntryVal(de);
-        
         if (o->type != REDIS_LIST) {
             addReply(c,shared.wrongtypeerr);
         } else {
@@ -2271,14 +2549,12 @@ static void lsetCommand(redisClient *c) {
 }
 
 static void popGenericCommand(redisClient *c, int where) {
-    dictEntry *de;
-    
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    robj *o;
+
+    o = lookupKeyWrite(c->db,c->argv[1]);
+    if (o == NULL) {
         addReply(c,shared.nullbulk);
     } else {
-        robj *o = dictGetEntryVal(de);
-        
         if (o->type != REDIS_LIST) {
             addReply(c,shared.wrongtypeerr);
         } else {
@@ -2313,16 +2589,14 @@ static void rpopCommand(redisClient *c) {
 }
 
 static void lrangeCommand(redisClient *c) {
-    dictEntry *de;
+    robj *o;
     int start = atoi(c->argv[2]->ptr);
     int end = atoi(c->argv[3]->ptr);
-    
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+
+    o = lookupKeyRead(c->db,c->argv[1]);
+    if (o == NULL) {
         addReply(c,shared.nullmultibulk);
     } else {
-        robj *o = dictGetEntryVal(de);
-        
         if (o->type != REDIS_LIST) {
             addReply(c,shared.wrongtypeerr);
         } else {
@@ -2362,16 +2636,14 @@ static void lrangeCommand(redisClient *c) {
 }
 
 static void ltrimCommand(redisClient *c) {
-    dictEntry *de;
+    robj *o;
     int start = atoi(c->argv[2]->ptr);
     int end = atoi(c->argv[3]->ptr);
     
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    o = lookupKeyWrite(c->db,c->argv[1]);
+    if (o == NULL) {
         addReply(c,shared.nokeyerr);
     } else {
-        robj *o = dictGetEntryVal(de);
-        
         if (o->type != REDIS_LIST) {
             addReply(c,shared.wrongtypeerr);
         } else {
@@ -2413,14 +2685,12 @@ static void ltrimCommand(redisClient *c) {
 }
 
 static void lremCommand(redisClient *c) {
-    dictEntry *de;
+    robj *o;
     
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    o = lookupKeyWrite(c->db,c->argv[1]);
+    if (o == NULL) {
         addReply(c,shared.nokeyerr);
     } else {
-        robj *o = dictGetEntryVal(de);
-        
         if (o->type != REDIS_LIST) {
             addReply(c,shared.wrongtypeerr);
         } else {
@@ -2436,8 +2706,9 @@ static void lremCommand(redisClient *c) {
             }
             ln = fromtail ? list->tail : list->head;
             while (ln) {
-                next = fromtail ? ln->prev : ln->next;
                 robj *ele = listNodeValue(ln);
+
+                next = fromtail ? ln->prev : ln->next;
                 if (sdscmp(ele->ptr,c->argv[3]->ptr) == 0) {
                     listDelNode(list,ln);
                     server.dirty++;
@@ -2454,16 +2725,14 @@ static void lremCommand(redisClient *c) {
 /* ==================================== Sets ================================ */
 
 static void saddCommand(redisClient *c) {
-    dictEntry *de;
     robj *set;
 
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    set = lookupKeyWrite(c->db,c->argv[1]);
+    if (set == NULL) {
         set = createSetObject();
-        dictAdd(c->dict,c->argv[1],set);
+        dictAdd(c->db->dict,c->argv[1],set);
         incrRefCount(c->argv[1]);
     } else {
-        set = dictGetEntryVal(de);
         if (set->type != REDIS_SET) {
             addReply(c,shared.wrongtypeerr);
             return;
@@ -2479,15 +2748,12 @@ static void saddCommand(redisClient *c) {
 }
 
 static void sremCommand(redisClient *c) {
-    dictEntry *de;
+    robj *set;
 
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    set = lookupKeyWrite(c->db,c->argv[1]);
+    if (set == NULL) {
         addReply(c,shared.czero);
     } else {
-        robj *set;
-
-        set = dictGetEntryVal(de);
         if (set->type != REDIS_SET) {
             addReply(c,shared.wrongtypeerr);
             return;
@@ -2502,15 +2768,12 @@ static void sremCommand(redisClient *c) {
 }
 
 static void sismemberCommand(redisClient *c) {
-    dictEntry *de;
+    robj *set;
 
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    set = lookupKeyRead(c->db,c->argv[1]);
+    if (set == NULL) {
         addReply(c,shared.czero);
     } else {
-        robj *set;
-
-        set = dictGetEntryVal(de);
         if (set->type != REDIS_SET) {
             addReply(c,shared.wrongtypeerr);
             return;
@@ -2523,21 +2786,20 @@ static void sismemberCommand(redisClient *c) {
 }
 
 static void scardCommand(redisClient *c) {
-    dictEntry *de;
+    robj *o;
     dict *s;
     
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    o = lookupKeyRead(c->db,c->argv[1]);
+    if (o == NULL) {
         addReply(c,shared.czero);
         return;
     } else {
-        robj *o = dictGetEntryVal(de);
         if (o->type != REDIS_SET) {
             addReply(c,shared.wrongtypeerr);
         } else {
             s = o->ptr;
             addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",
-                dictGetHashTableUsed(s)));
+                dictSize(s)));
         }
     }
 }
@@ -2545,7 +2807,7 @@ static void scardCommand(redisClient *c) {
 static int qsortCompareSetsByCardinality(const void *s1, const void *s2) {
     dict **d1 = (void*) s1, **d2 = (void*) s2;
 
-    return dictGetHashTableUsed(*d1)-dictGetHashTableUsed(*d2);
+    return dictSize(*d1)-dictSize(*d2);
 }
 
 static void sinterGenericCommand(redisClient *c, robj **setskeys, int setsnum, robj *dstkey) {
@@ -2558,15 +2820,15 @@ static void sinterGenericCommand(redisClient *c, robj **setskeys, int setsnum, r
     if (!dv) oom("sinterCommand");
     for (j = 0; j < setsnum; j++) {
         robj *setobj;
-        dictEntry *de;
-        
-        de = dictFind(c->dict,setskeys[j]);
-        if (!de) {
+
+        setobj = dstkey ?
+                    lookupKeyWrite(c->db,setskeys[j]) :
+                    lookupKeyRead(c->db,setskeys[j]);
+        if (!setobj) {
             zfree(dv);
             addReply(c,shared.nokeyerr);
             return;
         }
-        setobj = dictGetEntryVal(de);
         if (setobj->type != REDIS_SET) {
             zfree(dv);
             addReply(c,shared.wrongtypeerr);
@@ -2591,9 +2853,10 @@ static void sinterGenericCommand(redisClient *c, robj **setskeys, int setsnum, r
         /* If we have a target key where to store the resulting set
          * create this key with an empty set inside */
         dstset = createSetObject();
-        dictDelete(c->dict,dstkey);
-        dictAdd(c->dict,dstkey,dstset);
+        deleteKey(c->db,dstkey);
+        dictAdd(c->db->dict,dstkey,dstset);
         incrRefCount(dstkey);
+        server.dirty++;
     }
 
     /* Iterate all the elements of the first (smallest) set, and test
@@ -2618,6 +2881,7 @@ static void sinterGenericCommand(redisClient *c, robj **setskeys, int setsnum, r
         } else {
             dictAdd(dstset->ptr,ele,NULL);
             incrRefCount(ele);
+            server.dirty++;
         }
     }
     dictReleaseIterator(di);
@@ -2638,13 +2902,16 @@ static void sinterstoreCommand(redisClient *c) {
 }
 
 static void flushdbCommand(redisClient *c) {
-    dictEmpty(c->dict);
+    dictEmpty(c->db->dict);
+    dictEmpty(c->db->expires);
+    server.dirty++;
     addReply(c,shared.ok);
     rdbSave(server.dbfilename);
 }
 
 static void flushallCommand(redisClient *c) {
     emptyDb();
+    server.dirty++;
     addReply(c,shared.ok);
     rdbSave(server.dbfilename);
 }
@@ -2659,12 +2926,11 @@ redisSortOperation *createSortOperation(int type, robj *pattern) {
 
 /* Return the value associated to the key with a name obtained
  * substituting the first occurence of '*' in 'pattern' with 'subst' */
-robj *lookupKeyByPattern(dict *dict, robj *pattern, robj *subst) {
+robj *lookupKeyByPattern(redisDb *db, robj *pattern, robj *subst) {
     char *p;
     sds spat, ssub;
     robj keyobj;
     int prefixlen, sublen, postfixlen;
-    dictEntry *de;
     /* Expoit the internal sds representation to create a sds string allocated on the stack in order to make this function faster */
     struct {
         long len;
@@ -2672,7 +2938,6 @@ robj *lookupKeyByPattern(dict *dict, robj *pattern, robj *subst) {
         char buf[REDIS_SORTKEY_MAX+1];
     } keyname;
 
-
     spat = pattern->ptr;
     ssub = subst->ptr;
     if (sdslen(spat)+sdslen(ssub)-1 > REDIS_SORTKEY_MAX) return NULL;
@@ -2692,10 +2957,8 @@ robj *lookupKeyByPattern(dict *dict, robj *pattern, robj *subst) {
     keyobj.type = REDIS_STRING;
     keyobj.ptr = ((char*)&keyname)+(sizeof(long)*2);
 
-    de = dictFind(dict,&keyobj);
-    // printf("lookup '%s' => %p\n", keyname.buf,de);
-    if (!de) return NULL;
-    return dictGetEntryVal(de);
+    /* printf("lookup '%s' => %p\n", keyname.buf,de); */
+    return lookupKeyRead(db,&keyobj);
 }
 
 /* sortCompare() is used by qsort in sortCommand(). Given that qsort_r with
@@ -2740,7 +3003,6 @@ static int sortCompare(const void *s1, const void *s2) {
 /* The SORT command is the most complex command in Redis. Warning: this code
  * is optimized for speed and a bit less for readability */
 static void sortCommand(redisClient *c) {
-    dictEntry *de;
     list *operations;
     int outputlen = 0;
     int desc = 0, alpha = 0;
@@ -2751,12 +3013,11 @@ static void sortCommand(redisClient *c) {
     redisSortObject *vector; /* Resulting vector to sort */
 
     /* Lookup the key to sort. It must be of the right types */
-    de = dictFind(c->dict,c->argv[1]);
-    if (de == NULL) {
+    sortval = lookupKeyRead(c->db,c->argv[1]);
+    if (sortval == NULL) {
         addReply(c,shared.nokeyerr);
         return;
     }
-    sortval = dictGetEntryVal(de);
     if (sortval->type != REDIS_SET && sortval->type != REDIS_LIST) {
         addReply(c,shared.wrongtypeerr);
         return;
@@ -2821,7 +3082,7 @@ static void sortCommand(redisClient *c) {
     /* Load the sorting vector with all the objects to sort */
     vectorlen = (sortval->type == REDIS_LIST) ?
         listLength((list*)sortval->ptr) :
-        dictGetHashTableUsed((dict*)sortval->ptr);
+        dictSize((dict*)sortval->ptr);
     vector = zmalloc(sizeof(redisSortObject)*vectorlen);
     if (!vector) oom("allocating objects vector for SORT");
     j = 0;
@@ -2859,7 +3120,7 @@ static void sortCommand(redisClient *c) {
             if (sortby) {
                 robj *byval;
 
-                byval = lookupKeyByPattern(c->dict,sortby,vector[j].obj);
+                byval = lookupKeyByPattern(c->db,sortby,vector[j].obj);
                 if (!byval || byval->type != REDIS_STRING) continue;
                 if (alpha) {
                     vector[j].u.cmpobj = byval;
@@ -2904,7 +3165,7 @@ static void sortCommand(redisClient *c) {
         }
         while(ln) {
             redisSortOperation *sop = ln->value;
-            robj *val = lookupKeyByPattern(c->dict,sop->pattern,
+            robj *val = lookupKeyByPattern(c->db,sop->pattern,
                 vector[j].obj);
 
             if (sop->type == REDIS_SORT_GET) {
@@ -2941,7 +3202,7 @@ static void infoCommand(redisClient *c) {
         "redis_version:%s\r\n"
         "connected_clients:%d\r\n"
         "connected_slaves:%d\r\n"
-        "used_memory:%d\r\n"
+        "used_memory:%zu\r\n"
         "changes_since_last_save:%lld\r\n"
         "last_save_time:%d\r\n"
         "total_connections_received:%lld\r\n"
@@ -2964,6 +3225,98 @@ static void infoCommand(redisClient *c) {
     addReply(c,shared.crlf);
 }
 
+static void monitorCommand(redisClient *c) {
+    /* ignore MONITOR if aleady slave or in monitor mode */
+    if (c->flags & REDIS_SLAVE) return;
+
+    c->flags |= (REDIS_SLAVE|REDIS_MONITOR);
+    c->slaveseldb = 0;
+    if (!listAddNodeTail(server.monitors,c)) oom("listAddNodeTail");
+    addReply(c,shared.ok);
+}
+
+/* ================================= Expire ================================= */
+static int removeExpire(redisDb *db, robj *key) {
+    if (dictDelete(db->expires,key) == DICT_OK) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+static int setExpire(redisDb *db, robj *key, time_t when) {
+    if (dictAdd(db->expires,key,(void*)when) == DICT_ERR) {
+        return 0;
+    } else {
+        incrRefCount(key);
+        return 1;
+    }
+}
+
+/* Return the expire time of the specified key, or -1 if no expire
+ * is associated with this key (i.e. the key is non volatile) */
+static time_t getExpire(redisDb *db, robj *key) {
+    dictEntry *de;
+
+    /* No expire? return ASAP */
+    if (dictSize(db->expires) == 0 ||
+       (de = dictFind(db->expires,key)) == NULL) return -1;
+
+    return (time_t) dictGetEntryVal(de);
+}
+
+static int expireIfNeeded(redisDb *db, robj *key) {
+    time_t when;
+    dictEntry *de;
+
+    /* No expire? return ASAP */
+    if (dictSize(db->expires) == 0 ||
+       (de = dictFind(db->expires,key)) == NULL) return 0;
+
+    /* Lookup the expire */
+    when = (time_t) dictGetEntryVal(de);
+    if (time(NULL) <= when) return 0;
+
+    /* Delete the key */
+    dictDelete(db->expires,key);
+    return dictDelete(db->dict,key) == DICT_OK;
+}
+
+static int deleteIfVolatile(redisDb *db, robj *key) {
+    dictEntry *de;
+
+    /* No expire? return ASAP */
+    if (dictSize(db->expires) == 0 ||
+       (de = dictFind(db->expires,key)) == NULL) return 0;
+
+    /* Delete the key */
+    server.dirty++;
+    dictDelete(db->expires,key);
+    return dictDelete(db->dict,key) == DICT_OK;
+}
+
+static void expireCommand(redisClient *c) {
+    dictEntry *de;
+    int seconds = atoi(c->argv[2]->ptr);
+
+    de = dictFind(c->db->dict,c->argv[1]);
+    if (de == NULL) {
+        addReply(c,shared.czero);
+        return;
+    }
+    if (seconds <= 0) {
+        addReply(c, shared.czero);
+        return;
+    } else {
+        time_t when = time(NULL)+seconds;
+        if (setExpire(c->db,c->argv[1],when))
+            addReply(c,shared.cone);
+        else
+            addReply(c,shared.czero);
+        return;
+    }
+}
+
 /* =============================== Replication  ============================= */
 
 /* Send the whole output buffer syncronously to the slave. This a general operation in theory, but it is actually useful only for replication. */
@@ -2983,7 +3336,7 @@ static int flushClientOutput(redisClient *c) {
     return REDIS_OK;
 }
 
-static int syncWrite(int fd, void *ptr, ssize_t size, int timeout) {
+static int syncWrite(int fd, char *ptr, ssize_t size, int timeout) {
     ssize_t nwritten, ret = size;
     time_t start = time(NULL);
 
@@ -3003,7 +3356,7 @@ static int syncWrite(int fd, void *ptr, ssize_t size, int timeout) {
     return ret;
 }
 
-static int syncRead(int fd, void *ptr, ssize_t size, int timeout) {
+static int syncRead(int fd, char *ptr, ssize_t size, int timeout) {
     ssize_t nread, totread = 0;
     time_t start = time(NULL);
 
@@ -3164,16 +3517,6 @@ static int syncWithMaster(void) {
     return REDIS_OK;
 }
 
-static void monitorCommand(redisClient *c) {
-    /* ignore MONITOR if aleady slave or in monitor mode */
-    if (c->flags & REDIS_SLAVE) return;
-
-    c->flags |= (REDIS_SLAVE|REDIS_MONITOR);
-    c->slaveseldb = 0;
-    if (!listAddNodeTail(server.monitors,c)) oom("listAddNodeTail");
-    addReply(c,shared.ok);
-}
-
 /* =================================== Main! ================================ */
 
 static void daemonize(void) {