CONFIG SET maxclients.

src/config.c

@@ -541,10 +541,35 @@ void configSetCommand(redisClient *c) {
             }
             freeMemoryIfNeeded();
         }
+    } else if (!strcasecmp(c->argv[2]->ptr,"maxclients")) {
+        int orig_value = server.maxclients;
+
+        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
+
+        /* Try to check if the OS is capable of supporting so many FDs. */
+        server.maxclients = ll;
+        if (ll > orig_value) {
+            adjustOpenFilesLimit();
+            if (server.maxclients != ll) {
+                addReplyErrorFormat(c,"The operating system is not able to handle the specified number of clients, try with %d", server.maxclients);
+                server.maxclients = orig_value;
+                return;
+            }
+            if (aeGetSetSize(server.el) <
+                server.maxclients + REDIS_EVENTLOOP_FDSET_INCR)
+            {
+                if (aeResizeSetSize(server.el,
+                    server.maxclients + REDIS_EVENTLOOP_FDSET_INCR) == AE_ERR)
+                {
+                    addReplyError(c,"The event loop API used by Redis is not able to handle the specified number of clients");
+                    server.maxclients = orig_value;
+                    return;
+                }
+            }
+        }
     } else if (!strcasecmp(c->argv[2]->ptr,"hz")) {
-        if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
-            ll < 0) goto badfmt;
-        server.hz = (int) ll;
+        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
+        server.hz = ll;
         if (server.hz < REDIS_MIN_HZ) server.hz = REDIS_MIN_HZ;
         if (server.hz > REDIS_MAX_HZ) server.hz = REDIS_MAX_HZ;
     } else if (!strcasecmp(c->argv[2]->ptr,"maxmemory-policy")) {

src/redis.c

@@ -1382,7 +1382,7 @@ void initServer() {
 
     createSharedObjects();
     adjustOpenFilesLimit();
-    server.el = aeCreateEventLoop(server.maxclients+1024);
+    server.el = aeCreateEventLoop(server.maxclients+REDIS_EVENTLOOP_FDSET_INCR);
     server.db = zmalloc(sizeof(redisDb)*server.dbnum);
 
     if (server.port != 0) {

src/redis.h

@@ -129,6 +129,10 @@
 #define REDIS_MBULK_BIG_ARG     (1024*32)
 #define REDIS_LONGSTR_SIZE      21          /* Bytes needed for long -> str */
 #define REDIS_AOF_AUTOSYNC_BYTES (1024*1024*32) /* fdatasync every 32MB */
+/* When configuring the Redis eventloop, we setup it so that the total number
+ * of file descriptors we can handle are server.maxclients + FDSET_INCR
+ * that is our safety margin. */
+#define REDIS_EVENTLOOP_FDSET_INCR 128
 
 /* Hash table parameters */
 #define REDIS_HT_MINFILL        10      /* Minimal hash table fill 10% */
@@ -1072,6 +1076,7 @@ int htNeedsResize(dict *dict);
 void oom(const char *msg);
 void populateCommandTable(void);
 void resetCommandTableStats(void);
+void adjustOpenFilesLimit(void);
 
 /* Set data type */
 robj *setTypeCreate(robj *value);