Test: more MIGRATE tests.

[redis.git] / src / redis.c

diff --git a/src/redis.c b/src/redis.c
index 0a22d45d06221a371b44eb5205c2df3d7156b1e6..82dade155bf301efff9eeff66ed86f4bddd28a4b 100644 (file)
--- a/src/redis.c
+++ b/src/redis.c
@@ -1,5 +1,5 @@
 /*
 /*

- * Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>

  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without


@@ -110,6 +110,7 @@ struct redisCommand *commandTable;
  * t: Allow command while a slave has stale data but is not allowed to
  *    server this data. Normally no command is accepted in this condition
  *    but just a few.
  * t: Allow command while a slave has stale data but is not allowed to
  *    server this data. Normally no command is accepted in this condition
  *    but just a few.

+ * M: Do not automatically propagate the command on MONITOR.

  */
 struct redisCommand redisCommandTable[] = {
     {"get",getCommand,2,"r",0,NULL,1,1,1,0,0},
  */
 struct redisCommand redisCommandTable[] = {
     {"get",getCommand,2,"r",0,NULL,1,1,1,0,0},


@@ -152,7 +153,7 @@ struct redisCommand redisCommandTable[] = {
     {"sismember",sismemberCommand,3,"r",0,NULL,1,1,1,0,0},
     {"scard",scardCommand,2,"r",0,NULL,1,1,1,0,0},
     {"spop",spopCommand,2,"wRs",0,NULL,1,1,1,0,0},
     {"sismember",sismemberCommand,3,"r",0,NULL,1,1,1,0,0},
     {"scard",scardCommand,2,"r",0,NULL,1,1,1,0,0},
     {"spop",spopCommand,2,"wRs",0,NULL,1,1,1,0,0},

-    {"srandmember",srandmemberCommand,2,"rR",0,NULL,1,1,1,0,0},
+    {"srandmember",srandmemberCommand,-2,"rR",0,NULL,1,1,1,0,0},

     {"sinter",sinterCommand,-2,"rS",0,NULL,1,-1,1,0,0},
     {"sinterstore",sinterstoreCommand,-3,"wm",0,NULL,1,-1,1,0,0},
     {"sunion",sunionCommand,-2,"rS",0,NULL,1,-1,1,0,0},
     {"sinter",sinterCommand,-2,"rS",0,NULL,1,-1,1,0,0},
     {"sinterstore",sinterstoreCommand,-3,"wm",0,NULL,1,-1,1,0,0},
     {"sunion",sunionCommand,-2,"rS",0,NULL,1,-1,1,0,0},


@@ -216,13 +217,13 @@ struct redisCommand redisCommandTable[] = {
     {"lastsave",lastsaveCommand,1,"r",0,NULL,0,0,0,0,0},
     {"type",typeCommand,2,"r",0,NULL,1,1,1,0,0},
     {"multi",multiCommand,1,"rs",0,NULL,0,0,0,0,0},
     {"lastsave",lastsaveCommand,1,"r",0,NULL,0,0,0,0,0},
     {"type",typeCommand,2,"r",0,NULL,1,1,1,0,0},
     {"multi",multiCommand,1,"rs",0,NULL,0,0,0,0,0},

-    {"exec",execCommand,1,"s",0,NULL,0,0,0,0,0},
+    {"exec",execCommand,1,"sM",0,NULL,0,0,0,0,0},

     {"discard",discardCommand,1,"rs",0,NULL,0,0,0,0,0},
     {"sync",syncCommand,1,"ars",0,NULL,0,0,0,0,0},
     {"replconf",replconfCommand,-1,"ars",0,NULL,0,0,0,0,0},
     {"flushdb",flushdbCommand,1,"w",0,NULL,0,0,0,0,0},
     {"flushall",flushallCommand,1,"w",0,NULL,0,0,0,0,0},
     {"discard",discardCommand,1,"rs",0,NULL,0,0,0,0,0},
     {"sync",syncCommand,1,"ars",0,NULL,0,0,0,0,0},
     {"replconf",replconfCommand,-1,"ars",0,NULL,0,0,0,0,0},
     {"flushdb",flushdbCommand,1,"w",0,NULL,0,0,0,0,0},
     {"flushall",flushallCommand,1,"w",0,NULL,0,0,0,0,0},

-    {"sort",sortCommand,-2,"wmS",0,NULL,1,1,1,0,0},
+    {"sort",sortCommand,-2,"wm",0,NULL,1,1,1,0,0},

     {"info",infoCommand,-1,"rlt",0,NULL,0,0,0,0,0},
     {"monitor",monitorCommand,1,"ars",0,NULL,0,0,0,0,0},
     {"ttl",ttlCommand,2,"r",0,NULL,1,1,1,0,0},
     {"info",infoCommand,-1,"rlt",0,NULL,0,0,0,0,0},
     {"monitor",monitorCommand,1,"ars",0,NULL,0,0,0,0,0},
     {"ttl",ttlCommand,2,"r",0,NULL,1,1,1,0,0},


@@ -239,8 +240,8 @@ struct redisCommand redisCommandTable[] = {
     {"watch",watchCommand,-2,"rs",0,noPreloadGetKeys,1,-1,1,0,0},
     {"unwatch",unwatchCommand,1,"rs",0,NULL,0,0,0,0,0},
     {"cluster",clusterCommand,-2,"ar",0,NULL,0,0,0,0,0},
     {"watch",watchCommand,-2,"rs",0,noPreloadGetKeys,1,-1,1,0,0},
     {"unwatch",unwatchCommand,1,"rs",0,NULL,0,0,0,0,0},
     {"cluster",clusterCommand,-2,"ar",0,NULL,0,0,0,0,0},

-    {"restore",restoreCommand,4,"awm",0,NULL,1,1,1,0,0},
-    {"migrate",migrateCommand,6,"aw",0,NULL,0,0,0,0,0},
+    {"restore",restoreCommand,-4,"awm",0,NULL,1,1,1,0,0},
+    {"migrate",migrateCommand,-6,"aw",0,NULL,0,0,0,0,0},

     {"asking",askingCommand,1,"r",0,NULL,0,0,0,0,0},
     {"dump",dumpCommand,2,"ar",0,NULL,1,1,1,0,0},
     {"object",objectCommand,-2,"r",0,NULL,2,2,2,0,0},
     {"asking",askingCommand,1,"r",0,NULL,0,0,0,0,0},
     {"dump",dumpCommand,2,"ar",0,NULL,1,1,1,0,0},
     {"object",objectCommand,-2,"r",0,NULL,2,2,2,0,0},


@@ -560,6 +561,16 @@ dictType clusterNodesDictType = {
     NULL                        /* val destructor */
 };
 
     NULL                        /* val destructor */
 };
 

+/* Migrate cache dict type. */
+dictType migrateCacheDictType = {
+    dictSdsHash,                /* hash function */
+    NULL,                       /* key dup */
+    NULL,                       /* val dup */
+    dictSdsKeyCompare,          /* key compare */
+    dictSdsDestructor,          /* key destructor */
+    NULL                        /* val destructor */
+};
+

 int htNeedsResize(dict *dict) {
     long long size, used;
 
 int htNeedsResize(dict *dict) {
     long long size, used;
 


@@ -914,8 +925,12 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
 
             if (pid == server.rdb_child_pid) {
                 backgroundSaveDoneHandler(exitcode,bysignal);
 
             if (pid == server.rdb_child_pid) {
                 backgroundSaveDoneHandler(exitcode,bysignal);

-            } else {
+            } else if (pid == server.aof_child_pid) {

                 backgroundRewriteDoneHandler(exitcode,bysignal);
                 backgroundRewriteDoneHandler(exitcode,bysignal);

+            } else {
+                redisLog(REDIS_WARNING,
+                    "Warning, detected child with unmatched pid: %ld",
+                    (long)pid);

             }
             updateDictResizePolicy();
         }
             }
             updateDictResizePolicy();
         }


@@ -967,16 +982,21 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
      * to detect transfer failures. */
     run_with_period(1000) replicationCron();
 
      * to detect transfer failures. */
     run_with_period(1000) replicationCron();
 

-    /* Run other sub-systems specific cron jobs */
+    /* Run the Redis Cluster cron. */

     run_with_period(1000) {
         if (server.cluster_enabled) clusterCron();
     }
 
     run_with_period(1000) {
         if (server.cluster_enabled) clusterCron();
     }
 

-    /* Run the sentinel timer if we are in sentinel mode. */
+    /* Run the Sentinel timer if we are in sentinel mode. */

     run_with_period(100) {
         if (server.sentinel_mode) sentinelTimer();
     }
 
     run_with_period(100) {
         if (server.sentinel_mode) sentinelTimer();
     }
 

+    /* Cleanup expired MIGRATE cached sockets. */
+    run_with_period(1000) {
+        migrateCloseTimedoutSockets();
+    }
+

     server.cronloops++;
     return 1000/REDIS_HZ;
 }
     server.cronloops++;
     return 1000/REDIS_HZ;
 }


@@ -1027,7 +1047,7 @@ void createSharedObjects(void) {
     shared.pong = createObject(REDIS_STRING,sdsnew("+PONG\r\n"));
     shared.queued = createObject(REDIS_STRING,sdsnew("+QUEUED\r\n"));
     shared.wrongtypeerr = createObject(REDIS_STRING,sdsnew(
     shared.pong = createObject(REDIS_STRING,sdsnew("+PONG\r\n"));
     shared.queued = createObject(REDIS_STRING,sdsnew("+QUEUED\r\n"));
     shared.wrongtypeerr = createObject(REDIS_STRING,sdsnew(

-        "-ERR Operation against a key holding the wrong kind of value\r\n"));
+        "-WRONGTYPE Operation against a key holding the wrong kind of value\r\n"));

     shared.nokeyerr = createObject(REDIS_STRING,sdsnew(
         "-ERR no such key\r\n"));
     shared.syntaxerr = createObject(REDIS_STRING,sdsnew(
     shared.nokeyerr = createObject(REDIS_STRING,sdsnew(
         "-ERR no such key\r\n"));
     shared.syntaxerr = createObject(REDIS_STRING,sdsnew(


@@ -1067,6 +1087,7 @@ void createSharedObjects(void) {
     shared.del = createStringObject("DEL",3);
     shared.rpop = createStringObject("RPOP",4);
     shared.lpop = createStringObject("LPOP",4);
     shared.del = createStringObject("DEL",3);
     shared.rpop = createStringObject("RPOP",4);
     shared.lpop = createStringObject("LPOP",4);

+    shared.lpush = createStringObject("LPUSH",5);

     for (j = 0; j < REDIS_SHARED_INTEGERS; j++) {
         shared.integers[j] = createObject(REDIS_STRING,(void*)(long)j);
         shared.integers[j]->encoding = REDIS_ENCODING_INT;
     for (j = 0; j < REDIS_SHARED_INTEGERS; j++) {
         shared.integers[j] = createObject(REDIS_STRING,(void*)(long)j);
         shared.integers[j]->encoding = REDIS_ENCODING_INT;


@@ -1143,6 +1164,7 @@ void initServerConfig() {
     server.lua_time_limit = REDIS_LUA_TIME_LIMIT;
     server.lua_client = NULL;
     server.lua_timedout = 0;
     server.lua_time_limit = REDIS_LUA_TIME_LIMIT;
     server.lua_client = NULL;
     server.lua_timedout = 0;

+    server.migrate_cached_sockets = dictCreate(&migrateCacheDictType,NULL);

 
     updateLRUClock();
     resetServerSaveParams();
 
     updateLRUClock();
     resetServerSaveParams();


@@ -1187,6 +1209,8 @@ void initServerConfig() {
     server.delCommand = lookupCommandByCString("del");
     server.multiCommand = lookupCommandByCString("multi");
     server.lpushCommand = lookupCommandByCString("lpush");
     server.delCommand = lookupCommandByCString("del");
     server.multiCommand = lookupCommandByCString("multi");
     server.lpushCommand = lookupCommandByCString("lpush");

+    server.lpopCommand = lookupCommandByCString("lpop");
+    server.rpopCommand = lookupCommandByCString("rpop");

     
     /* Slow log */
     server.slowlog_log_slower_than = REDIS_SLOWLOG_LOG_SLOWER_THAN;
     
     /* Slow log */
     server.slowlog_log_slower_than = REDIS_SLOWLOG_LOG_SLOWER_THAN;


@@ -1262,6 +1286,7 @@ void initServer() {
     server.slaves = listCreate();
     server.monitors = listCreate();
     server.unblocked_clients = listCreate();
     server.slaves = listCreate();
     server.monitors = listCreate();
     server.unblocked_clients = listCreate();

+    server.ready_keys = listCreate();

 
     createSharedObjects();
     adjustOpenFilesLimit();
 
     createSharedObjects();
     adjustOpenFilesLimit();


@@ -1292,6 +1317,7 @@ void initServer() {
         server.db[j].dict = dictCreate(&dbDictType,NULL);
         server.db[j].expires = dictCreate(&keyptrDictType,NULL);
         server.db[j].blocking_keys = dictCreate(&keylistDictType,NULL);
         server.db[j].dict = dictCreate(&dbDictType,NULL);
         server.db[j].expires = dictCreate(&keyptrDictType,NULL);
         server.db[j].blocking_keys = dictCreate(&keylistDictType,NULL);

+        server.db[j].ready_keys = dictCreate(&setDictType,NULL);

         server.db[j].watched_keys = dictCreate(&keylistDictType,NULL);
         server.db[j].id = j;
     }
         server.db[j].watched_keys = dictCreate(&keylistDictType,NULL);
         server.db[j].id = j;
     }


@@ -1343,11 +1369,11 @@ void initServer() {
 
     /* 32 bit instances are limited to 4GB of address space, so if there is
      * no explicit limit in the user provided configuration we set a limit
 
     /* 32 bit instances are limited to 4GB of address space, so if there is
      * no explicit limit in the user provided configuration we set a limit

-     * at 3.5GB using maxmemory with 'noeviction' policy'. This saves
-     * useless crashes of the Redis instance. */
+     * at 3 GB using maxmemory with 'noeviction' policy'. This avoids
+     * useless crashes of the Redis instance for out of memory. */

     if (server.arch_bits == 32 && server.maxmemory == 0) {
     if (server.arch_bits == 32 && server.maxmemory == 0) {

-        redisLog(REDIS_WARNING,"Warning: 32 bit instance detected but no memory limit set. Setting 3.5 GB maxmemory limit with 'noeviction' policy now.");
-        server.maxmemory = 3584LL*(1024*1024); /* 3584 MB = 3.5 GB */
+        redisLog(REDIS_WARNING,"Warning: 32 bit instance detected but no memory limit set. Setting 3 GB maxmemory limit with 'noeviction' policy now.");
+        server.maxmemory = 3072LL*(1024*1024); /* 3 GB */

         server.maxmemory_policy = REDIS_MAXMEMORY_NO_EVICTION;
     }
 
         server.maxmemory_policy = REDIS_MAXMEMORY_NO_EVICTION;
     }
 


@@ -1381,6 +1407,7 @@ void populateCommandTable(void) {
             case 'S': c->flags |= REDIS_CMD_SORT_FOR_SCRIPT; break;
             case 'l': c->flags |= REDIS_CMD_LOADING; break;
             case 't': c->flags |= REDIS_CMD_STALE; break;
             case 'S': c->flags |= REDIS_CMD_SORT_FOR_SCRIPT; break;
             case 'l': c->flags |= REDIS_CMD_LOADING; break;
             case 't': c->flags |= REDIS_CMD_STALE; break;

+            case 'M': c->flags |= REDIS_CMD_SKIP_MONITOR; break;

             default: redisPanic("Unsupported command flag"); break;
             }
             f++;
             default: redisPanic("Unsupported command flag"); break;
             }
             f++;


@@ -1456,7 +1483,7 @@ struct redisCommand *lookupCommandByCString(char *s) {
 }
 
 /* Propagate the specified command (in the context of the specified database id)
 }
 
 /* Propagate the specified command (in the context of the specified database id)

- * to AOF, Slaves and Monitors.
+ * to AOF and Slaves.

  *
  * flags are an xor between:
  * + REDIS_PROPAGATE_NONE (no propagation of command at all)
  *
  * flags are an xor between:
  * + REDIS_PROPAGATE_NONE (no propagation of command at all)


@@ -1486,8 +1513,12 @@ void call(redisClient *c, int flags) {
 
     /* Sent the command to clients in MONITOR mode, only if the commands are
      * not geneated from reading an AOF. */
 
     /* Sent the command to clients in MONITOR mode, only if the commands are
      * not geneated from reading an AOF. */

-    if (listLength(server.monitors) && !server.loading)
+    if (listLength(server.monitors) &&
+        !server.loading &&
+        !(c->cmd->flags & REDIS_CMD_SKIP_MONITOR))
+    {

         replicationFeedMonitors(c,server.monitors,c->db->id,c->argv,c->argc);
         replicationFeedMonitors(c,server.monitors,c->db->id,c->argv,c->argc);

+    }

 
     /* Call the command. */
     redisOpArrayInit(&server.also_propagate);
 
     /* Call the command. */
     redisOpArrayInit(&server.also_propagate);


@@ -1537,7 +1568,7 @@ void call(redisClient *c, int flags) {
 }
 
 /* If this function gets called we already read a whole
 }
 
 /* If this function gets called we already read a whole

- * command, argments are in the client argv/argc fields.
+ * command, arguments are in the client argv/argc fields.

  * processCommand() execute the command or prepare the
  * server for a bulk read from the client.
  *
  * processCommand() execute the command or prepare the
  * server for a bulk read from the client.
  *


@@ -1662,6 +1693,7 @@ int processCommand(redisClient *c) {
 
     /* Lua script too slow? Only allow commands with REDIS_CMD_STALE flag. */
     if (server.lua_timedout &&
 
     /* Lua script too slow? Only allow commands with REDIS_CMD_STALE flag. */
     if (server.lua_timedout &&

+          c->cmd->proc != authCommand &&

         !(c->cmd->proc == shutdownCommand &&
           c->argc == 2 &&
           tolower(((char*)c->argv[1]->ptr)[0]) == 'n') &&
         !(c->cmd->proc == shutdownCommand &&
           c->argc == 2 &&
           tolower(((char*)c->argv[1]->ptr)[0]) == 'n') &&


@@ -1682,6 +1714,8 @@ int processCommand(redisClient *c) {
         addReply(c,shared.queued);
     } else {
         call(c,REDIS_CALL_FULL);
         addReply(c,shared.queued);
     } else {
         call(c,REDIS_CALL_FULL);

+        if (listLength(server.ready_keys))
+            handleClientsBlockedOnLists();

     }
     return REDIS_OK;
 }
     }
     return REDIS_OK;
 }


@@ -1849,7 +1883,7 @@ sds genRedisInfoString(char *section) {
     unsigned long lol, bib;
     int allsections = 0, defsections = 0;
     int sections = 0;
     unsigned long lol, bib;
     int allsections = 0, defsections = 0;
     int sections = 0;

-    
+

     if (section) {
         allsections = strcasecmp(section,"all") == 0;
         defsections = strcasecmp(section,"default") == 0;
     if (section) {
         allsections = strcasecmp(section,"all") == 0;
         defsections = strcasecmp(section,"default") == 0;


@@ -1862,7 +1896,12 @@ sds genRedisInfoString(char *section) {
     /* Server */
     if (allsections || defsections || !strcasecmp(section,"server")) {
         struct utsname name;
     /* Server */
     if (allsections || defsections || !strcasecmp(section,"server")) {
         struct utsname name;

+        char *mode;

 
 

+        if (server.cluster_enabled) mode = "cluster";
+        else if (server.sentinel_mode) mode = "sentinel";
+        else mode = "standalone";
+    

         if (sections++) info = sdscat(info,"\r\n");
         uname(&name);
         info = sdscatprintf(info,
         if (sections++) info = sdscat(info,"\r\n");
         uname(&name);
         info = sdscatprintf(info,


@@ -1870,6 +1909,7 @@ sds genRedisInfoString(char *section) {
             "redis_version:%s\r\n"
             "redis_git_sha1:%s\r\n"
             "redis_git_dirty:%d\r\n"
             "redis_version:%s\r\n"
             "redis_git_sha1:%s\r\n"
             "redis_git_dirty:%d\r\n"

+            "redis_mode:%s\r\n"

             "os:%s %s %s\r\n"
             "arch_bits:%d\r\n"
             "multiplexing_api:%s\r\n"
             "os:%s %s %s\r\n"
             "arch_bits:%d\r\n"
             "multiplexing_api:%s\r\n"


@@ -1883,6 +1923,7 @@ sds genRedisInfoString(char *section) {
             REDIS_VERSION,
             redisGitSHA1(),
             strtol(redisGitDirty(),NULL,10) > 0,
             REDIS_VERSION,
             redisGitSHA1(),
             strtol(redisGitDirty(),NULL,10) > 0,

+            mode,

             name.sysname, name.release, name.machine,
             server.arch_bits,
             aeGetApiName(),
             name.sysname, name.release, name.machine,
             server.arch_bits,
             aeGetApiName(),


@@ -1982,7 +2023,7 @@ sds genRedisInfoString(char *section) {
                 "aof_base_size:%lld\r\n"
                 "aof_pending_rewrite:%d\r\n"
                 "aof_buffer_length:%zu\r\n"
                 "aof_base_size:%lld\r\n"
                 "aof_pending_rewrite:%d\r\n"
                 "aof_buffer_length:%zu\r\n"

-                "aof_rewrite_buffer_length:%zu\r\n"
+                "aof_rewrite_buffer_length:%lu\r\n"

                 "aof_pending_bio_fsync:%llu\r\n"
                 "aof_delayed_fsync:%lu\r\n",
                 (long long) server.aof_current_size,
                 "aof_pending_bio_fsync:%llu\r\n"
                 "aof_delayed_fsync:%lu\r\n",
                 (long long) server.aof_current_size,


@@ -2041,7 +2082,8 @@ sds genRedisInfoString(char *section) {
             "keyspace_misses:%lld\r\n"
             "pubsub_channels:%ld\r\n"
             "pubsub_patterns:%lu\r\n"
             "keyspace_misses:%lld\r\n"
             "pubsub_channels:%ld\r\n"
             "pubsub_patterns:%lu\r\n"

-            "latest_fork_usec:%lld\r\n",
+            "latest_fork_usec:%lld\r\n"
+            "migrate_cached_sockets:%ld\r\n",

             server.stat_numconnections,
             server.stat_numcommands,
             getOperationsPerSecond(),
             server.stat_numconnections,
             server.stat_numcommands,
             getOperationsPerSecond(),


@@ -2052,7 +2094,8 @@ sds genRedisInfoString(char *section) {
             server.stat_keyspace_misses,
             dictSize(server.pubsub_channels),
             listLength(server.pubsub_patterns),
             server.stat_keyspace_misses,
             dictSize(server.pubsub_channels),
             listLength(server.pubsub_patterns),

-            server.stat_fork_time);
+            server.stat_fork_time,
+            dictSize(server.migrate_cached_sockets));

     }
 
     /* Replication */
     }
 
     /* Replication */


@@ -2094,7 +2137,10 @@ sds genRedisInfoString(char *section) {
                     (long)server.unixtime-server.repl_down_since);
             }
             info = sdscatprintf(info,
                     (long)server.unixtime-server.repl_down_since);
             }
             info = sdscatprintf(info,

-                "slave_priority:%d\r\n", server.slave_priority);
+                "slave_priority:%d\r\n"
+                "slave_read_only:%d\r\n",
+                server.slave_priority,
+                server.repl_slave_ro);

         }
         info = sdscatprintf(info,
             "connected_slaves:%lu\r\n",
         }
         info = sdscatprintf(info,
             "connected_slaves:%lu\r\n",


@@ -2205,7 +2251,7 @@ void infoCommand(redisClient *c) {
 }
 
 void monitorCommand(redisClient *c) {
 }
 
 void monitorCommand(redisClient *c) {

-    /* ignore MONITOR if aleady slave or in monitor mode */
+    /* ignore MONITOR if already slave or in monitor mode */

     if (c->flags & REDIS_SLAVE) return;
 
     c->flags |= (REDIS_SLAVE|REDIS_MONITOR);
     if (c->flags & REDIS_SLAVE) return;
 
     c->flags |= (REDIS_SLAVE|REDIS_MONITOR);


@@ -2304,7 +2350,7 @@ int freeMemoryIfNeeded(void) {
 
                     de = dictGetRandomKey(dict);
                     thiskey = dictGetKey(de);
 
                     de = dictGetRandomKey(dict);
                     thiskey = dictGetKey(de);

-                    /* When policy is volatile-lru we need an additonal lookup
+                    /* When policy is volatile-lru we need an additional 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);
                      * 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);


@@ -2607,7 +2653,7 @@ int main(int argc, char **argv) {
     redisAsciiArt();
 
     if (!server.sentinel_mode) {
     redisAsciiArt();
 
     if (!server.sentinel_mode) {

-        /* Things only needed when not runnign in Sentinel mode. */
+        /* Things only needed when not running in Sentinel mode. */

         redisLog(REDIS_WARNING,"Server started, Redis version " REDIS_VERSION);
     #ifdef __linux__
         linuxOvercommitMemoryWarning();
         redisLog(REDIS_WARNING,"Server started, Redis version " REDIS_VERSION);
     #ifdef __linux__
         linuxOvercommitMemoryWarning();


@@ -2619,6 +2665,11 @@ int main(int argc, char **argv) {
             redisLog(REDIS_NOTICE,"The server is now ready to accept connections at %s", server.unixsocket);
     }
 
             redisLog(REDIS_NOTICE,"The server is now ready to accept connections at %s", server.unixsocket);
     }
 

+    /* Warning the user about suspicious maxmemory setting. */
+    if (server.maxmemory > 0 && server.maxmemory < 1024*1024) {
+        redisLog(REDIS_WARNING,"WARNING: You specified a maxmemory value that is less than 1MB (current value is %llu bytes). Are you sure this is what you really want?", server.maxmemory);
+    }
+

     aeSetBeforeSleepProc(server.el,beforeSleep);
     aeMain(server.el);
     aeDeleteEventLoop(server.el);
     aeSetBeforeSleepProc(server.el,beforeSleep);
     aeMain(server.el);
     aeDeleteEventLoop(server.el);