Replication: send REPLCONF ACK to master.

src/networking.c

@@ -127,7 +127,8 @@ redisClient *createClient(int fd) {
  * data should be appended to the output buffers. */
 int prepareClientToWrite(redisClient *c) {
     if (c->flags & REDIS_LUA_CLIENT) return REDIS_OK;
-    if (c->flags & REDIS_MASTER) return REDIS_ERR;
+    if ((c->flags & REDIS_MASTER) &&
+        !(c->flags & REDIS_MASTER_FORCE_REPLY)) return REDIS_ERR;
     if (c->fd <= 0) return REDIS_ERR; /* Fake client */
     if (c->bufpos == 0 && listLength(c->reply) == 0 &&
         (c->replstate == REDIS_REPL_NONE ||

src/redis.c

@@ -1868,6 +1868,15 @@ int processCommand(redisClient *c) {
         call(c,REDIS_CALL_FULL);
         if (listLength(server.ready_keys))
             handleClientsBlockedOnLists();
+        /* Acknowledge the master about the execution of this command. */
+        if (c->flags & REDIS_MASTER) {
+            c->flags |= REDIS_MASTER_FORCE_REPLY;
+            addReplyMultiBulkLen(c,3);
+            addReplyBulkCString(c,"REPLCONF");
+            addReplyBulkCString(c,"ACK");
+            addReplyBulkLongLong(c,c->reploff);
+            c->flags &= ~REDIS_MASTER_FORCE_REPLY;
+        }
     }
     return REDIS_OK;
 }
@@ -2337,8 +2346,9 @@ sds genRedisInfoString(char *section) {
                     break;
                 }
                 if (state == NULL) continue;
-                info = sdscatprintf(info,"slave%d:%s,%d,%s\r\n",
-                    slaveid,ip,slave->slave_listening_port,state);
+                info = sdscatprintf(info,"slave%d:%s,%d,%s,%lld\r\n",
+                    slaveid,ip,slave->slave_listening_port,state,
+                    slave->repl_ack_off);
                 slaveid++;
             }
         }

src/redis.h

@@ -213,6 +213,7 @@
 #define REDIS_CLOSE_ASAP (1<<10)/* Close this client ASAP */
 #define REDIS_UNIX_SOCKET (1<<11) /* Client connected via Unix domain socket */
 #define REDIS_DIRTY_EXEC (1<<12)  /* EXEC will fail for errors while queueing */
+#define REDIS_MASTER_FORCE_REPLY (1<<13)  /* Queue replies even if is master */
 
 /* Client request types */
 #define REDIS_REQ_INLINE 1