Permit keys of differing slots as long as they are served by this cluster and we are not migrating

Author: JohnSully

src/cluster.cpp

@@ -5952,6 +5952,7 @@ clusterNode *getNodeByQuery(client *c, struct redisCommand *cmd, robj **argv, in
         numkeys = getKeysFromCommand(mcmd,margv,margc,&result);
         keyindex = result.keys;
 
+        bool fFirstKeyThisServer = false;
         for (j = 0; j < numkeys; j++) {
             robj *thiskey = margv[keyindex[j]];
             int thisslot = keyHashSlot((char*)ptrFromObj(thiskey),
@@ -5987,10 +5988,19 @@ clusterNode *getNodeByQuery(client *c, struct redisCommand *cmd, robj **argv, in
                 } else if (g_pserver->cluster->importing_slots_from[slot] != NULL) {
                     importing_slot = 1;
                 }
+
+                if (n == myself && !importing_slot && !migrating_slot) {
+                    fFirstKeyThisServer = true;
+                }
             } else {
                 /* If it is not the first key, make sure it is exactly
                  * the same key as the first we saw. */
                 if (!equalStringObjects(firstkey,thiskey)) {
+                    clusterNode* nThisKey = g_pserver->cluster->slots[slot];
+                    if (fFirstKeyThisServer && nThisKey == myself && g_pserver->cluster->migrating_slots_to[slot] == nullptr && g_pserver->cluster->importing_slots_from[slot] == nullptr) {
+                        continue;
+                    }
+
                     if (slot != thisslot) {
                         /* Error: multiple keys from different slots. */
                         getKeysFreeResult(&result);

src/server.cpp

@@ -5663,7 +5663,8 @@ sds genRedisInfoString(const char *section) {
             "lru_clock:%u\r\n"
             "executable:%s\r\n"
             "config_file:%s\r\n"
-            "availability_zone:%s\r\n",
+            "availability_zone:%s\r\n"
+            "features:%s\r\n",
             KEYDB_SET_VERSION,
             redisGitSHA1(),
             strtol(redisGitDirty(),NULL,10) > 0,
@@ -5690,7 +5691,8 @@ sds genRedisInfoString(const char *section) {
             lruclock,
             cserver.executable ? cserver.executable : "",
             cserver.configfile ? cserver.configfile : "",
-            g_pserver->sdsAvailabilityZone);
+            g_pserver->sdsAvailabilityZone,
+            "cluster_mget");
     }
 
     /* Clients */