minor changes to doc and comments
[redis.git] / src / redis.c
index 30fe807d3c87380c320526d8b31732222fd2ebd7..65cf3ace9c045b1fbcffa6347aba51f37dc87626 100644 (file)
@@ -74,10 +74,14 @@ struct redisCommand readonlyCommandTable[] = {
     {"setnx",setnxCommand,3,REDIS_CMD_DENYOOM,NULL,0,0,0},
     {"setex",setexCommand,4,REDIS_CMD_DENYOOM,NULL,0,0,0},
     {"append",appendCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
-    {"substr",substrCommand,4,0,NULL,1,1,1},
     {"strlen",strlenCommand,2,0,NULL,1,1,1},
     {"del",delCommand,-2,0,NULL,0,0,0},
     {"exists",existsCommand,2,0,NULL,1,1,1},
+    {"setbit",setbitCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"getbit",getbitCommand,3,0,NULL,1,1,1},
+    {"setrange",setrangeCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"getrange",getrangeCommand,4,0,NULL,1,1,1},
+    {"substr",getrangeCommand,4,0,NULL,1,1,1},
     {"incr",incrCommand,2,REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"decr",decrCommand,2,REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"mget",mgetCommand,-2,0,NULL,1,-1,1},
@@ -89,6 +93,7 @@ struct redisCommand readonlyCommandTable[] = {
     {"rpop",rpopCommand,2,0,NULL,1,1,1},
     {"lpop",lpopCommand,2,0,NULL,1,1,1},
     {"brpop",brpopCommand,-3,0,NULL,1,1,1},
+    {"brpoplpush",brpoplpushCommand,4,REDIS_CMD_DENYOOM,NULL,1,2,1},
     {"blpop",blpopCommand,-3,0,NULL,1,1,1},
     {"llen",llenCommand,2,0,NULL,1,1,1},
     {"lindex",lindexCommand,3,0,NULL,1,1,1},
@@ -96,7 +101,7 @@ struct redisCommand readonlyCommandTable[] = {
     {"lrange",lrangeCommand,4,0,NULL,1,1,1},
     {"ltrim",ltrimCommand,4,0,NULL,1,1,1},
     {"lrem",lremCommand,4,0,NULL,1,1,1},
-    {"rpoplpush",rpoplpushcommand,3,REDIS_CMD_DENYOOM,NULL,1,2,1},
+    {"rpoplpush",rpoplpushCommand,3,REDIS_CMD_DENYOOM,NULL,1,2,1},
     {"sadd",saddCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"srem",sremCommand,3,0,NULL,1,1,1},
     {"smove",smoveCommand,4,0,NULL,1,2,1},
@@ -124,7 +129,7 @@ struct redisCommand readonlyCommandTable[] = {
     {"zcount",zcountCommand,4,0,NULL,1,1,1},
     {"zrevrange",zrevrangeCommand,-4,0,NULL,1,1,1},
     {"zcard",zcardCommand,2,0,NULL,1,1,1},
-    {"zscore",zscoreCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"zscore",zscoreCommand,3,0,NULL,1,1,1},
     {"zrank",zrankCommand,3,0,NULL,1,1,1},
     {"zrevrank",zrevrankCommand,3,0,NULL,1,1,1},
     {"hset",hsetCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
@@ -188,11 +193,13 @@ struct redisCommand readonlyCommandTable[] = {
 /*============================ Utility functions ============================ */
 
 void redisLog(int level, const char *fmt, ...) {
+    const int syslogLevelMap[] = { LOG_DEBUG, LOG_INFO, LOG_NOTICE, LOG_WARNING };
+    const char *c = ".-*#";
+    time_t now = time(NULL);
     va_list ap;
     FILE *fp;
-    char *c = ".-*#";
     char buf[64];
-    time_t now;
+    char msg[REDIS_MAX_LOGMSG_LEN];
 
     if (level < server.verbosity) return;
 
@@ -200,15 +207,16 @@ void redisLog(int level, const char *fmt, ...) {
     if (!fp) return;
 
     va_start(ap, fmt);
-    now = time(NULL);
-    strftime(buf,64,"%d %b %H:%M:%S",localtime(&now));
-    fprintf(fp,"[%d] %s %c ",(int)getpid(),buf,c[level]);
-    vfprintf(fp, fmt, ap);
-    fprintf(fp,"\n");
-    fflush(fp);
+    vsnprintf(msg, sizeof(msg), fmt, ap);
     va_end(ap);
 
+    strftime(buf,sizeof(buf),"%d %b %H:%M:%S",localtime(&now));
+    fprintf(fp,"[%d] %s %c %s\n",(int)getpid(),buf,c[level],msg);
+    fflush(fp);
+
     if (server.logfile) fclose(fp);
+
+    if (server.syslog_enabled) syslog(syslogLevelMap[level], "%s", msg);
 }
 
 /* Redis generally does not try to recover from out of memory conditions
@@ -337,7 +345,7 @@ unsigned int dictEncObjHash(const void *key) {
     }
 }
 
-/* Sets type */
+/* Sets type and diskstore negative caching hash table */
 dictType setDictType = {
     dictEncObjHash,            /* hash function */
     NULL,                      /* key dup */
@@ -572,7 +580,7 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
     }
 
     /* Close connections of timedout clients */
-    if ((server.maxidletime && !(loops % 100)) || server.blpop_blocked_clients)
+    if ((server.maxidletime && !(loops % 100)) || server.bpop_blocked_clients)
         closeTimedoutClients();
 
     /* Check if a background saving or AOF rewrite in progress terminated */
@@ -588,7 +596,7 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
             }
             updateDictResizePolicy();
         }
-    } else {
+    } else if (!server.ds_enabled) {
         /* If there is not a background saving in progress check if
          * we have to save now */
          time_t now = time(NULL);
@@ -610,40 +618,14 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
      * in order to guarantee a strict consistency. */
     if (server.masterhost == NULL) activeExpireCycle();
 
-    /* Swap a few keys on disk if we are over the memory limit and VM
-     * is enbled. Try to free objects from the free list first. */
-    if (vmCanSwapOut()) {
-        while (server.vm_enabled && zmalloc_used_memory() >
-                server.vm_max_memory)
-        {
-            int retval;
-
-            if (tryFreeOneObjectFromFreelist() == REDIS_OK) continue;
-            retval = (server.vm_max_threads == 0) ?
-                        vmSwapOneObjectBlocking() :
-                        vmSwapOneObjectThreaded();
-            if (retval == REDIS_ERR && !(loops % 300) &&
-                zmalloc_used_memory() >
-                (server.vm_max_memory+server.vm_max_memory/10))
-            {
-                redisLog(REDIS_WARNING,"WARNING: vm-max-memory limit exceeded by more than 10%% but unable to swap more objects out!");
-            }
-            /* Note that when using threade I/O we free just one object,
-             * because anyway when the I/O thread in charge to swap this
-             * object out will finish, the handler of completed jobs
-             * will try to swap more objects if we are still out of memory. */
-            if (retval == REDIS_ERR || server.vm_max_threads > 0) break;
-        }
-    }
+    /* Remove a few cached objects from memory if we are over the
+     * configured memory limit */
+    if (server.ds_enabled) cacheCron();
+
+    /* Replication cron function -- used to reconnect to master and
+     * to detect transfer failures. */
+    if (!(loops % 10)) replicationCron();
 
-    /* Check if we should connect to a MASTER */
-    if (server.replstate == REDIS_REPL_CONNECT && !(loops % 10)) {
-        redisLog(REDIS_NOTICE,"Connecting to MASTER...");
-        if (syncWithMaster() == REDIS_OK) {
-            redisLog(REDIS_NOTICE,"MASTER <-> SLAVE sync succeeded");
-            if (server.appendonly) rewriteAppendOnlyFileBackground();
-        }
-    }
     return 100;
 }
 
@@ -652,21 +634,22 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
  * for ready file descriptors. */
 void beforeSleep(struct aeEventLoop *eventLoop) {
     REDIS_NOTUSED(eventLoop);
+    listNode *ln;
+    redisClient *c;
 
-    /* Awake clients that got all the swapped keys they requested */
-    if (server.vm_enabled && listLength(server.io_ready_clients)) {
+    /* Awake clients that got all the on disk keys they requested */
+    if (server.ds_enabled && listLength(server.io_ready_clients)) {
         listIter li;
-        listNode *ln;
 
         listRewind(server.io_ready_clients,&li);
         while((ln = listNext(&li))) {
-            redisClient *c = ln->value;
+            c = ln->value;
             struct redisCommand *cmd;
 
             /* Resume the client. */
             listDelNode(server.io_ready_clients,ln);
             c->flags &= (~REDIS_IO_WAIT);
-            server.vm_blocked_clients--;
+            server.cache_blocked_clients--;
             aeCreateFileEvent(server.el, c->fd, AE_READABLE,
                 readQueryFromClient, c);
             cmd = lookupCommand(c->argv[0]->ptr);
@@ -678,6 +661,19 @@ void beforeSleep(struct aeEventLoop *eventLoop) {
                 processInputBuffer(c);
         }
     }
+
+    /* Try to process pending commands for clients that were just unblocked. */
+    while (listLength(server.unblocked_clients)) {
+        ln = listFirst(server.unblocked_clients);
+        redisAssert(ln != NULL);
+        c = ln->value;
+        listDelNode(server.unblocked_clients,ln);
+
+        /* Process remaining data in the input buffer. */
+        if (c->querybuf && sdslen(c->querybuf) > 0)
+            processInputBuffer(c);
+    }
+
     /* Write the AOF buffer on disk */
     flushAppendOnlyFile();
 }
@@ -709,6 +705,8 @@ void createSharedObjects(void) {
         "-ERR source and destination objects are the same\r\n"));
     shared.outofrangeerr = createObject(REDIS_STRING,sdsnew(
         "-ERR index out of range\r\n"));
+    shared.loadingerr = createObject(REDIS_STRING,sdsnew(
+        "-LOADING Redis is loading the dataset in memory\r\n"));
     shared.space = createObject(REDIS_STRING,sdsnew(" "));
     shared.colon = createObject(REDIS_STRING,sdsnew(":"));
     shared.plus = createObject(REDIS_STRING,sdsnew("+"));
@@ -746,7 +744,11 @@ void initServerConfig() {
     server.verbosity = REDIS_VERBOSE;
     server.maxidletime = REDIS_MAXIDLETIME;
     server.saveparams = NULL;
+    server.loading = 0;
     server.logfile = NULL; /* NULL = log on standard output */
+    server.syslog_enabled = 0;
+    server.syslog_ident = zstrdup("redis");
+    server.syslog_facility = LOG_LOCAL0;
     server.glueoutputbuf = 1;
     server.daemonize = 0;
     server.appendonly = 0;
@@ -762,17 +764,14 @@ void initServerConfig() {
     server.rdbcompression = 1;
     server.activerehashing = 1;
     server.maxclients = 0;
-    server.blpop_blocked_clients = 0;
+    server.bpop_blocked_clients = 0;
     server.maxmemory = 0;
     server.maxmemory_policy = REDIS_MAXMEMORY_VOLATILE_LRU;
     server.maxmemory_samples = 3;
-    server.vm_enabled = 0;
-    server.vm_swap_file = zstrdup("/tmp/redis-%p.vm");
-    server.vm_page_size = 256;          /* 256 bytes per page */
-    server.vm_pages = 1024*1024*100;    /* 104 millions of pages */
-    server.vm_max_memory = 1024LL*1024*1024*1; /* 1 GB of RAM */
-    server.vm_max_threads = 4;
-    server.vm_blocked_clients = 0;
+    server.ds_enabled = 0;
+    server.ds_path = sdsnew("/tmp/redis.ds");
+    server.cache_max_memory = 64LL*1024*1024; /* 64 MB of RAM */
+    server.cache_blocked_clients = 0;
     server.hash_max_zipmap_entries = REDIS_HASH_MAX_ZIPMAP_ENTRIES;
     server.hash_max_zipmap_value = REDIS_HASH_MAX_ZIPMAP_VALUE;
     server.list_max_ziplist_entries = REDIS_LIST_MAX_ZIPLIST_ENTRIES;
@@ -793,6 +792,7 @@ void initServerConfig() {
     server.masterport = 6379;
     server.master = NULL;
     server.replstate = REDIS_REPL_NONE;
+    server.repl_serve_stale_data = 1;
 
     /* Double constants initialization */
     R_Zero = 0.0;
@@ -816,16 +816,19 @@ void initServer() {
     signal(SIGPIPE, SIG_IGN);
     setupSigSegvAction();
 
-    server.mainthread = pthread_self();
-    server.devnull = fopen("/dev/null","w");
-    if (server.devnull == NULL) {
-        redisLog(REDIS_WARNING, "Can't open /dev/null: %s", server.neterr);
-        exit(1);
+    if (server.syslog_enabled) {
+        openlog(server.syslog_ident, LOG_PID | LOG_NDELAY | LOG_NOWAIT,
+            server.syslog_facility);
     }
+
+    server.mainthread = pthread_self();
     server.clients = listCreate();
     server.slaves = listCreate();
     server.monitors = listCreate();
-    server.objfreelist = listCreate();
+    server.unblocked_clients = listCreate();
+    server.cache_flush_queue = listCreate();
+    server.cache_flush_delay = 0;
+
     createSharedObjects();
     server.el = aeCreateEventLoop();
     server.db = zmalloc(sizeof(redisDb)*server.dbnum);
@@ -851,8 +854,10 @@ void initServer() {
         server.db[j].expires = dictCreate(&keyptrDictType,NULL);
         server.db[j].blocking_keys = dictCreate(&keylistDictType,NULL);
         server.db[j].watched_keys = dictCreate(&keylistDictType,NULL);
-        if (server.vm_enabled)
+        if (server.ds_enabled) {
             server.db[j].io_keys = dictCreate(&keylistDictType,NULL);
+            server.db[j].io_negcache = dictCreate(&setDictType,NULL);
+        }
         server.db[j].id = j;
     }
     server.pubsub_channels = dictCreate(&keylistDictType,NULL);
@@ -869,6 +874,7 @@ void initServer() {
     server.stat_numcommands = 0;
     server.stat_numconnections = 0;
     server.stat_expiredkeys = 0;
+    server.stat_evictedkeys = 0;
     server.stat_starttime = time(NULL);
     server.stat_keyspace_misses = 0;
     server.stat_keyspace_hits = 0;
@@ -888,7 +894,7 @@ void initServer() {
         }
     }
 
-    if (server.vm_enabled) vmInit();
+    if (server.ds_enabled) dsInit();
 }
 
 /* Populates the Redis Command Table starting from the hard coded list
@@ -1002,6 +1008,23 @@ int processCommand(redisClient *c) {
         return REDIS_OK;
     }
 
+    /* Only allow INFO and SLAVEOF when slave-serve-stale-data is no and
+     * we are a slave with a broken link with master. */
+    if (server.masterhost && server.replstate != REDIS_REPL_CONNECTED &&
+        server.repl_serve_stale_data == 0 &&
+        cmd->proc != infoCommand && cmd->proc != slaveofCommand)
+    {
+        addReplyError(c,
+            "link with MASTER is down and slave-serve-stale-data is set to no");
+        return REDIS_OK;
+    }
+
+    /* Loading DB? Return an error if the command is not INFO */
+    if (server.loading && cmd->proc != infoCommand) {
+        addReply(c, shared.loadingerr);
+        return REDIS_OK;
+    }
+
     /* Exec the command */
     if (c->flags & REDIS_MULTI &&
         cmd->proc != execCommand && cmd->proc != discardCommand &&
@@ -1010,8 +1033,8 @@ int processCommand(redisClient *c) {
         queueMultiCommand(c,cmd);
         addReply(c,shared.queued);
     } else {
-        if (server.vm_enabled && server.vm_max_threads > 0 &&
-            blockClientOnSwappedKeys(c,cmd)) return REDIS_ERR;
+        if (server.ds_enabled && blockClientOnSwappedKeys(c,cmd))
+            return REDIS_ERR;
         call(c,cmd);
     }
     return REDIS_OK;
@@ -1029,10 +1052,11 @@ int prepareForShutdown() {
         kill(server.bgsavechildpid,SIGKILL);
         rdbRemoveTempFile(server.bgsavechildpid);
     }
-    if (server.appendonly) {
+    if (server.ds_enabled) {
+        /* FIXME: flush all objects on disk */
+    } else if (server.appendonly) {
         /* Append only file: fsync() the AOF and exit */
         aof_fsync(server.appendfd);
-        if (server.vm_enabled) unlink(server.vm_swap_file);
     } else if (server.saveparamslen > 0) {
         /* Snapshotting. Perform a SYNC SAVE and exit */
         if (rdbSave(server.dbfilename) != REDIS_OK) {
@@ -1129,6 +1153,8 @@ sds genRedisInfoString(void) {
         "used_memory_rss:%zu\r\n"
         "mem_fragmentation_ratio:%.2f\r\n"
         "use_tcmalloc:%d\r\n"
+        "loading:%d\r\n"
+        "aof_enabled:%d\r\n"
         "changes_since_last_save:%lld\r\n"
         "bgsave_in_progress:%d\r\n"
         "last_save_time:%ld\r\n"
@@ -1136,13 +1162,14 @@ sds genRedisInfoString(void) {
         "total_connections_received:%lld\r\n"
         "total_commands_processed:%lld\r\n"
         "expired_keys:%lld\r\n"
+        "evicted_keys:%lld\r\n"
         "keyspace_hits:%lld\r\n"
         "keyspace_misses:%lld\r\n"
         "hash_max_zipmap_entries:%zu\r\n"
         "hash_max_zipmap_value:%zu\r\n"
         "pubsub_channels:%ld\r\n"
         "pubsub_patterns:%u\r\n"
-        "vm_enabled:%d\r\n"
+        "ds_enabled:%d\r\n"
         "role:%s\r\n"
         ,REDIS_VERSION,
         redisGitSHA1(),
@@ -1159,7 +1186,7 @@ sds genRedisInfoString(void) {
         (float)c_ru.ru_stime.tv_sec+(float)c_ru.ru_stime.tv_usec/1000000,
         listLength(server.clients)-listLength(server.slaves),
         listLength(server.slaves),
-        server.blpop_blocked_clients,
+        server.bpop_blocked_clients,
         zmalloc_used_memory(),
         hmem,
         zmalloc_get_rss(),
@@ -1169,6 +1196,8 @@ sds genRedisInfoString(void) {
 #else
         0,
 #endif
+        server.loading,
+        server.appendonly,
         server.dirty,
         server.bgsavechildpid != -1,
         server.lastsave,
@@ -1176,13 +1205,14 @@ sds genRedisInfoString(void) {
         server.stat_numconnections,
         server.stat_numcommands,
         server.stat_expiredkeys,
+        server.stat_evictedkeys,
         server.stat_keyspace_hits,
         server.stat_keyspace_misses,
         server.hash_max_zipmap_entries,
         server.hash_max_zipmap_value,
         dictSize(server.pubsub_channels),
         listLength(server.pubsub_patterns),
-        server.vm_enabled != 0,
+        server.ds_enabled != 0,
         server.masterhost == NULL ? "master" : "slave"
     );
     if (server.masterhost) {
@@ -1191,43 +1221,63 @@ sds genRedisInfoString(void) {
             "master_port:%d\r\n"
             "master_link_status:%s\r\n"
             "master_last_io_seconds_ago:%d\r\n"
+            "master_sync_in_progress:%d\r\n"
             ,server.masterhost,
             server.masterport,
             (server.replstate == REDIS_REPL_CONNECTED) ?
                 "up" : "down",
-            server.master ? ((int)(time(NULL)-server.master->lastinteraction)) : -1
+            server.master ? ((int)(time(NULL)-server.master->lastinteraction)) : -1,
+            server.replstate == REDIS_REPL_TRANSFER
         );
+
+        if (server.replstate == REDIS_REPL_TRANSFER) {
+            info = sdscatprintf(info,
+                "master_sync_left_bytes:%ld\r\n"
+                "master_sync_last_io_seconds_ago:%d\r\n"
+                ,(long)server.repl_transfer_left,
+                (int)(time(NULL)-server.repl_transfer_lastio)
+            );
+        }
     }
-    if (server.vm_enabled) {
+    if (server.ds_enabled) {
         lockThreadedIO();
         info = sdscatprintf(info,
-            "vm_conf_max_memory:%llu\r\n"
-            "vm_conf_page_size:%llu\r\n"
-            "vm_conf_pages:%llu\r\n"
-            "vm_stats_used_pages:%llu\r\n"
-            "vm_stats_swapped_objects:%llu\r\n"
-            "vm_stats_swappin_count:%llu\r\n"
-            "vm_stats_swappout_count:%llu\r\n"
-            "vm_stats_io_newjobs_len:%lu\r\n"
-            "vm_stats_io_processing_len:%lu\r\n"
-            "vm_stats_io_processed_len:%lu\r\n"
-            "vm_stats_io_active_threads:%lu\r\n"
-            "vm_stats_blocked_clients:%lu\r\n"
-            ,(unsigned long long) server.vm_max_memory,
-            (unsigned long long) server.vm_page_size,
-            (unsigned long long) server.vm_pages,
-            (unsigned long long) server.vm_stats_used_pages,
-            (unsigned long long) server.vm_stats_swapped_objects,
-            (unsigned long long) server.vm_stats_swapins,
-            (unsigned long long) server.vm_stats_swapouts,
-            (unsigned long) listLength(server.io_newjobs),
-            (unsigned long) listLength(server.io_processing),
-            (unsigned long) listLength(server.io_processed),
-            (unsigned long) server.io_active_threads,
-            (unsigned long) server.vm_blocked_clients
+            "cache_max_memory:%llu\r\n"
+            "cache_blocked_clients:%lu\r\n"
+            ,(unsigned long long) server.cache_max_memory,
+            (unsigned long) server.cache_blocked_clients
         );
         unlockThreadedIO();
     }
+    if (server.loading) {
+        double perc;
+        time_t eta, elapsed;
+        off_t remaining_bytes = server.loading_total_bytes-
+                                server.loading_loaded_bytes;
+
+        perc = ((double)server.loading_loaded_bytes /
+               server.loading_total_bytes) * 100;
+
+        elapsed = time(NULL)-server.loading_start_time;
+        if (elapsed == 0) {
+            eta = 1; /* A fake 1 second figure if we don't have enough info */
+        } else {
+            eta = (elapsed*remaining_bytes)/server.loading_loaded_bytes;
+        }
+
+        info = sdscatprintf(info,
+            "loading_start_time:%ld\r\n"
+            "loading_total_bytes:%llu\r\n"
+            "loading_loaded_bytes:%llu\r\n"
+            "loading_loaded_perc:%.2f\r\n"
+            "loading_eta_seconds:%ld\r\n"
+            ,(unsigned long) server.loading_start_time,
+            (unsigned long long) server.loading_total_bytes,
+            (unsigned long long) server.loading_loaded_bytes,
+            perc,
+            eta
+        );
+    }
     for (j = 0; j < server.dbnum; j++) {
         long long keys, vkeys;
 
@@ -1261,27 +1311,6 @@ void monitorCommand(redisClient *c) {
 
 /* ============================ Maxmemory directive  ======================== */
 
-/* Try to free one object form the pre-allocated objects free list.
- * This is useful under low mem conditions as by default we take 1 million
- * free objects allocated. On success REDIS_OK is returned, otherwise
- * REDIS_ERR. */
-int tryFreeOneObjectFromFreelist(void) {
-    robj *o;
-
-    if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
-    if (listLength(server.objfreelist)) {
-        listNode *head = listFirst(server.objfreelist);
-        o = listNodeValue(head);
-        listDelNode(server.objfreelist,head);
-        if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
-        zfree(o);
-        return REDIS_OK;
-    } else {
-        if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
-        return REDIS_ERR;
-    }
-}
-
 /* This function gets called when 'maxmemory' is set on the config file to limit
  * the max memory used by the server, and we are out of memory.
  * This function will try to, in order:
@@ -1296,12 +1325,11 @@ int tryFreeOneObjectFromFreelist(void) {
 void freeMemoryIfNeeded(void) {
     /* Remove keys accordingly to the active policy as long as we are
      * over the memory limit. */
+    if (server.maxmemory_policy == REDIS_MAXMEMORY_NO_EVICTION) return;
+
     while (server.maxmemory && zmalloc_used_memory() > server.maxmemory) {
         int j, k, freed = 0;
 
-        /* Basic strategy -- remove objects from the free list. */
-        if (tryFreeOneObjectFromFreelist() == REDIS_OK) continue;
-
         for (j = 0; j < server.dbnum; j++) {
             long bestval = 0; /* just to prevent warning */
             sds bestkey = NULL;
@@ -1337,6 +1365,10 @@ void freeMemoryIfNeeded(void) {
 
                     de = dictGetRandomKey(dict);
                     thiskey = dictGetEntryKey(de);
+                    /* When policy is volatile-lru we need an additonal lookup
+                     * to locate the real key, as dict is set to db->expires. */
+                    if (server.maxmemory_policy == REDIS_MAXMEMORY_VOLATILE_LRU)
+                        de = dictFind(db->dict, thiskey);
                     o = dictGetEntryVal(de);
                     thisval = estimateObjectIdleTime(o);
 
@@ -1371,44 +1403,13 @@ void freeMemoryIfNeeded(void) {
             if (bestkey) {
                 robj *keyobj = createStringObject(bestkey,sdslen(bestkey));
                 dbDelete(db,keyobj);
-                server.stat_expiredkeys++;
+                server.stat_evictedkeys++;
                 decrRefCount(keyobj);
                 freed++;
             }
         }
         if (!freed) return; /* nothing to free... */
     }
-
-    while(0) {
-        int j, k, freed = 0;
-        for (j = 0; j < server.dbnum; j++) {
-            int minttl = -1;
-            sds minkey = NULL;
-            robj *keyobj = NULL;
-            struct dictEntry *de;
-
-            if (dictSize(server.db[j].expires)) {
-                freed = 1;
-                /* From a sample of three keys drop the one nearest to
-                 * the natural expire */
-                for (k = 0; k < 3; k++) {
-                    time_t t;
-
-                    de = dictGetRandomKey(server.db[j].expires);
-                    t = (time_t) dictGetEntryVal(de);
-                    if (minttl == -1 || t < minttl) {
-                        minkey = dictGetEntryKey(de);
-                        minttl = t;
-                    }
-                }
-                keyobj = createStringObject(minkey,sdslen(minkey));
-                dbDelete(server.db+j,keyobj);
-                server.stat_expiredkeys++;
-                decrRefCount(keyobj);
-            }
-        }
-        if (!freed) return; /* nothing to free... */
-    }
 }
 
 /* =================================== Main! ================================ */
@@ -1496,7 +1497,9 @@ int main(int argc, char **argv) {
     linuxOvercommitMemoryWarning();
 #endif
     start = time(NULL);
-    if (server.appendonly) {
+    if (server.ds_enabled) {
+        redisLog(REDIS_NOTICE,"DB not loaded (running with disk back end)");
+    } else if (server.appendonly) {
         if (loadAppendOnlyFile(server.appendfilename) == REDIS_OK)
             redisLog(REDIS_NOTICE,"DB loaded from append only file: %ld seconds",time(NULL)-start);
     } else {