X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/726a39c15ff5d89f0d44a32cca8869cf0589f929..632e4c09acad87b999dd944413ac5b75207de571:/src/cluster.c diff --git a/src/cluster.c b/src/cluster.c index 46350cc2..3e65af78 100644 --- a/src/cluster.c +++ b/src/cluster.c @@ -11,6 +11,9 @@ void clusterSendFail(char *nodename); void clusterUpdateState(void); int clusterNodeGetSlotBit(clusterNode *n, int slot); sds clusterGenNodesDescription(void); +clusterNode *clusterLookupNode(char *name); +int clusterNodeAddSlave(clusterNode *master, clusterNode *slave); +int clusterAddSlot(clusterNode *n, int slot); /* ----------------------------------------------------------------------------- * Initialization @@ -21,12 +24,10 @@ void clusterGetRandomName(char *p) { char *charset = "0123456789abcdef"; int j; - if (!fp) { - redisLog(REDIS_WARNING, - "Unrecovarable error: can't open /dev/urandom:%s" ,strerror(errno)); - exit(1); + if (fp == NULL || fread(p,REDIS_CLUSTER_NAMELEN,1,fp) == 0) { + for (j = 0; j < REDIS_CLUSTER_NAMELEN; j++) + p[j] = rand(); } - fread(p,REDIS_CLUSTER_NAMELEN,1,fp); for (j = 0; j < REDIS_CLUSTER_NAMELEN; j++) p[j] = charset[p[j] & 0x0F]; fclose(fp); @@ -35,7 +36,7 @@ void clusterGetRandomName(char *p) { int clusterLoadConfig(char *filename) { FILE *fp = fopen(filename,"r"); char *line; - int maxline; + int maxline, j; if (fp == NULL) return REDIS_ERR; @@ -48,8 +49,102 @@ int clusterLoadConfig(char *filename) { while(fgets(line,maxline,fp) != NULL) { int argc; sds *argv = sdssplitargs(line,&argc); + clusterNode *n, *master; + char *p, *s; + + /* Create this node if it does not exist */ + n = clusterLookupNode(argv[0]); + if (!n) { + n = createClusterNode(argv[0],0); + clusterAddNode(n); + } + /* Address and port */ + if ((p = strchr(argv[1],':')) == NULL) goto fmterr; + *p = '\0'; + memcpy(n->ip,argv[1],strlen(argv[1])+1); + n->port = atoi(p+1); + + /* Parse flags */ + p = s = argv[2]; + while(p) { + p = strchr(s,','); + if (p) *p = '\0'; + if (!strcasecmp(s,"myself")) { + redisAssert(server.cluster.myself == NULL); + server.cluster.myself = n; + n->flags |= REDIS_NODE_MYSELF; + } else if (!strcasecmp(s,"master")) { + n->flags |= REDIS_NODE_MASTER; + } else if (!strcasecmp(s,"slave")) { + n->flags |= REDIS_NODE_SLAVE; + } else if (!strcasecmp(s,"fail?")) { + n->flags |= REDIS_NODE_PFAIL; + } else if (!strcasecmp(s,"fail")) { + n->flags |= REDIS_NODE_FAIL; + } else if (!strcasecmp(s,"handshake")) { + n->flags |= REDIS_NODE_HANDSHAKE; + } else if (!strcasecmp(s,"noaddr")) { + n->flags |= REDIS_NODE_NOADDR; + } else if (!strcasecmp(s,"noflags")) { + /* nothing to do */ + } else { + redisPanic("Unknown flag in redis cluster config file"); + } + if (p) s = p+1; + } - printf("Node: %s\n", argv[0]); + /* Get master if any. Set the master and populate master's + * slave list. */ + if (argv[3][0] != '-') { + master = clusterLookupNode(argv[3]); + if (!master) { + master = createClusterNode(argv[3],0); + clusterAddNode(master); + } + n->slaveof = master; + clusterNodeAddSlave(master,n); + } + + /* Set ping sent / pong received timestamps */ + if (atoi(argv[4])) n->ping_sent = time(NULL); + if (atoi(argv[5])) n->pong_received = time(NULL); + + /* Populate hash slots served by this instance. */ + for (j = 7; j < argc; j++) { + int start, stop; + + if (argv[j][0] == '[') { + /* Here we handle migrating / importing slots */ + int slot; + char direction; + clusterNode *cn; + + p = strchr(argv[j],'-'); + redisAssert(p != NULL); + *p = '\0'; + direction = p[1]; /* Either '>' or '<' */ + slot = atoi(argv[j]+1); + p += 3; + cn = clusterLookupNode(p); + if (!cn) { + cn = createClusterNode(p,0); + clusterAddNode(cn); + } + if (direction == '>') { + server.cluster.migrating_slots_to[slot] = cn; + } else { + server.cluster.importing_slots_from[slot] = cn; + } + continue; + } else if ((p = strchr(argv[j],'-')) != NULL) { + *p = '\0'; + start = atoi(argv[j]); + stop = atoi(p+1); + } else { + start = stop = atoi(argv[j]); + } + while(start <= stop) clusterAddSlot(n, start++); + } sdssplitargs_free(argv,argc); } @@ -57,11 +152,10 @@ int clusterLoadConfig(char *filename) { fclose(fp); /* Config sanity check */ - /* TODO: check that myself is set. */ - return REDIS_ERR; - + redisAssert(server.cluster.myself != NULL); redisLog(REDIS_NOTICE,"Node configuration loaded, I'm %.40s", server.cluster.myself->name); + clusterUpdateState(); return REDIS_OK; fmterr: @@ -100,7 +194,7 @@ void clusterSaveConfigOrDie(void) { void clusterInit(void) { int saveconf = 0; - server.cluster.myself = createClusterNode(NULL,REDIS_NODE_MYSELF); + server.cluster.myself = NULL; server.cluster.state = REDIS_CLUSTER_FAIL; server.cluster.nodes = dictCreate(&clusterNodesDictType,NULL); server.cluster.node_timeout = 15; @@ -113,6 +207,7 @@ void clusterInit(void) { if (clusterLoadConfig(server.cluster.configfile) == REDIS_ERR) { /* No configuration found. We will just use the random name provided * by the createClusterNode() function. */ + server.cluster.myself = createClusterNode(NULL,REDIS_NODE_MYSELF); redisLog(REDIS_NOTICE,"No cluster configuration found, I'm %.40s", server.cluster.myself->name); clusterAddNode(server.cluster.myself); @@ -128,6 +223,7 @@ void clusterInit(void) { } if (aeCreateFileEvent(server.el, server.cfd, AE_READABLE, clusterAcceptHandler, NULL) == AE_ERR) oom("creating file event"); + server.cluster.slots_to_keys = zslCreate(); } /* ----------------------------------------------------------------------------- @@ -437,6 +533,7 @@ int clusterProcessPacket(clusterLink *link) { sender = clusterLookupNode(hdr->sender); if (type == CLUSTERMSG_TYPE_PING || type == CLUSTERMSG_TYPE_MEET) { + int update_config = 0; redisLog(REDIS_DEBUG,"Ping packet received: %p", link->node); /* Add this node if it is new for us and the msg type is MEET. @@ -450,6 +547,7 @@ int clusterProcessPacket(clusterLink *link) { nodeIp2String(node->ip,link); node->port = ntohs(hdr->port); clusterAddNode(node); + update_config = 1; } /* Get info from the gossip section */ @@ -457,8 +555,12 @@ int clusterProcessPacket(clusterLink *link) { /* Anyway reply with a PONG */ clusterSendPing(link,CLUSTERMSG_TYPE_PONG); + + /* Update config if needed */ + if (update_config) clusterSaveConfigOrDie(); } else if (type == CLUSTERMSG_TYPE_PONG) { - int update = 0; + int update_state = 0; + int update_config = 0; redisLog(REDIS_DEBUG,"Pong packet received: %p", link->node); if (link->node) { @@ -479,6 +581,7 @@ int clusterProcessPacket(clusterLink *link) { redisLog(REDIS_DEBUG,"Handshake with node %.40s completed.", link->node->name); link->node->flags &= ~REDIS_NODE_HANDSHAKE; + update_config = 1; } else if (memcmp(link->node->name,hdr->sender, REDIS_CLUSTER_NAMELEN) != 0) { @@ -488,6 +591,7 @@ int clusterProcessPacket(clusterLink *link) { redisLog(REDIS_DEBUG,"PONG contains mismatching sender ID"); link->node->flags |= REDIS_NODE_NOADDR; freeClusterLink(link); + update_config = 1; /* FIXME: remove this node if we already have it. * * If we already have it but the IP is different, use @@ -533,7 +637,7 @@ int clusterProcessPacket(clusterLink *link) { server.cluster.slots[j]->flags & REDIS_NODE_FAIL) { server.cluster.slots[j] = sender; - update = 1; + update_state = update_config = 1; } } } @@ -544,15 +648,14 @@ int clusterProcessPacket(clusterLink *link) { clusterProcessGossipSection(hdr,link); /* Update the cluster state if needed */ - if (update) { - clusterUpdateState(); - clusterSaveConfigOrDie(); - } + if (update_state) clusterUpdateState(); + if (update_config) clusterSaveConfigOrDie(); } else if (type == CLUSTERMSG_TYPE_FAIL && sender) { clusterNode *failing; failing = clusterLookupNode(hdr->data.fail.about.nodename); - if (failing && !(failing->flags & REDIS_NODE_FAIL)) { + if (failing && !(failing->flags & (REDIS_NODE_FAIL|REDIS_NODE_MYSELF))) + { redisLog(REDIS_NOTICE, "FAIL message received from %.40s about %.40s", hdr->sender, hdr->data.fail.about.nodename); @@ -810,7 +913,7 @@ void clusterCron(void) { * normal PING packets. */ node->flags &= ~REDIS_NODE_MEET; - redisLog(REDIS_NOTICE,"Connecting with Node %.40s at %s:%d\n", node->name, node->ip, node->port+REDIS_CLUSTER_PORT_INCR); + redisLog(REDIS_NOTICE,"Connecting with Node %.40s at %s:%d", node->name, node->ip, node->port+REDIS_CLUSTER_PORT_INCR); } } dictReleaseIterator(di); @@ -840,22 +943,34 @@ void clusterCron(void) { int delay; if (node->flags & - (REDIS_NODE_MYSELF|REDIS_NODE_NOADDR|REDIS_NODE_HANDSHAKE| - REDIS_NODE_FAIL)) continue; + (REDIS_NODE_MYSELF|REDIS_NODE_NOADDR|REDIS_NODE_HANDSHAKE)) + continue; /* Check only if we already sent a ping and did not received * a reply yet. */ if (node->ping_sent == 0 || node->ping_sent <= node->pong_received) continue; delay = time(NULL) - node->pong_received; - if (node->flags & REDIS_NODE_PFAIL) { + if (delay < server.cluster.node_timeout) { /* The PFAIL condition can be reversed without external * help if it is not transitive (that is, if it does not - * turn into a FAIL state). */ - if (delay < server.cluster.node_timeout) + * turn into a FAIL state). + * + * The FAIL condition is also reversible if there are no slaves + * for this host, so no slave election should be in progress. + * + * TODO: consider all the implications of resurrecting a + * FAIL node. */ + if (node->flags & REDIS_NODE_PFAIL) { node->flags &= ~REDIS_NODE_PFAIL; + } else if (node->flags & REDIS_NODE_FAIL && !node->numslaves) { + node->flags &= ~REDIS_NODE_FAIL; + clusterUpdateState(); + } } else { - if (delay >= server.cluster.node_timeout) { + /* Timeout reached. Set the noad se possibly failing if it is + * not already in this state. */ + if (!(node->flags & (REDIS_NODE_PFAIL|REDIS_NODE_FAIL))) { redisLog(REDIS_DEBUG,"*** NODE %.40s possibly failing", node->name); node->flags |= REDIS_NODE_PFAIL; @@ -899,9 +1014,21 @@ int clusterNodeGetSlotBit(clusterNode *n, int slot) { * If the slot is already assigned to another instance this is considered * an error and REDIS_ERR is returned. */ int clusterAddSlot(clusterNode *n, int slot) { - redisAssert(clusterNodeSetSlotBit(n,slot) == 0); - server.cluster.slots[slot] = server.cluster.myself; - printf("SLOT %d added to %.40s\n", slot, n->name); + if (clusterNodeSetSlotBit(n,slot) != 0) + return REDIS_ERR; + server.cluster.slots[slot] = n; + return REDIS_OK; +} + +/* Delete the specified slot marking it as unassigned. + * Returns REDIS_OK if the slot was assigned, otherwise if the slot was + * already unassigned REDIS_ERR is returned. */ +int clusterDelSlot(int slot) { + clusterNode *n = server.cluster.slots[slot]; + + if (!n) return REDIS_ERR; + redisAssert(clusterNodeClearSlotBit(n,slot) == 1); + server.cluster.slots[slot] = NULL; return REDIS_OK; } @@ -993,12 +1120,39 @@ sds clusterGenNodesDescription(void) { start = -1; } } + + /* Just for MYSELF node we also dump info about slots that + * we are migrating to other instances or importing from other + * instances. */ + if (node->flags & REDIS_NODE_MYSELF) { + for (j = 0; j < REDIS_CLUSTER_SLOTS; j++) { + if (server.cluster.migrating_slots_to[j]) { + ci = sdscatprintf(ci," [%d->-%.40s]",j, + server.cluster.migrating_slots_to[j]->name); + } else if (server.cluster.importing_slots_from[j]) { + ci = sdscatprintf(ci," [%d-<-%.40s]",j, + server.cluster.importing_slots_from[j]->name); + } + } + } + ci = sdscatlen(ci,"\n",1); } - ci = sdscatlen(ci,"\n",1); dictReleaseIterator(di); return ci; } +int getSlotOrReply(redisClient *c, robj *o) { + long long slot; + + if (getLongLongFromObject(o,&slot) != REDIS_OK || + slot < 0 || slot > REDIS_CLUSTER_SLOTS) + { + addReplyError(c,"Invalid or out of range slot"); + return -1; + } + return (int) slot; +} + void clusterCommand(redisClient *c) { if (server.cluster_enabled == 0) { addReplyError(c,"This instance has cluster support disabled"); @@ -1036,24 +1190,26 @@ void clusterCommand(redisClient *c) { o = createObject(REDIS_STRING,ci); addReplyBulk(c,o); decrRefCount(o); - } else if (!strcasecmp(c->argv[1]->ptr,"addslots") && c->argc >= 3) { - int j; - long long slot; + } else if ((!strcasecmp(c->argv[1]->ptr,"addslots") || + !strcasecmp(c->argv[1]->ptr,"delslots")) && c->argc >= 3) { + int j, slot; unsigned char *slots = zmalloc(REDIS_CLUSTER_SLOTS); + int del = !strcasecmp(c->argv[1]->ptr,"delslots"); memset(slots,0,REDIS_CLUSTER_SLOTS); /* Check that all the arguments are parsable and that all the * slots are not already busy. */ for (j = 2; j < c->argc; j++) { - if (getLongLongFromObject(c->argv[j],&slot) != REDIS_OK || - slot < 0 || slot > REDIS_CLUSTER_SLOTS) - { - addReplyError(c,"Invalid or out of range slot index"); + if ((slot = getSlotOrReply(c,c->argv[j])) == -1) { zfree(slots); return; } - if (server.cluster.slots[slot]) { - addReplyErrorFormat(c,"Slot %lld is already busy", slot); + if (del && server.cluster.slots[slot] == NULL) { + addReplyErrorFormat(c,"Slot %d is already unassigned", slot); + zfree(slots); + return; + } else if (!del && server.cluster.slots[slot]) { + addReplyErrorFormat(c,"Slot %d is already busy", slot); zfree(slots); return; } @@ -1066,8 +1222,15 @@ void clusterCommand(redisClient *c) { } for (j = 0; j < REDIS_CLUSTER_SLOTS; j++) { if (slots[j]) { - int retval = clusterAddSlot(server.cluster.myself,j); - + int retval; + + /* If this slot was set as importing we can clear this + * state as now we are the real owner of the slot. */ + if (server.cluster.importing_slots_from[j]) + server.cluster.importing_slots_from[j] = NULL; + + retval = del ? clusterDelSlot(j) : + clusterAddSlot(server.cluster.myself,j); redisAssert(retval == REDIS_OK); } } @@ -1075,6 +1238,79 @@ void clusterCommand(redisClient *c) { clusterUpdateState(); clusterSaveConfigOrDie(); addReply(c,shared.ok); + } else if (!strcasecmp(c->argv[1]->ptr,"setslot") && c->argc >= 4) { + /* SETSLOT 10 MIGRATING */ + /* SETSLOT 10 IMPORTING */ + /* SETSLOT 10 STABLE */ + int slot; + clusterNode *n; + + if ((slot = getSlotOrReply(c,c->argv[2])) == -1) return; + + if (!strcasecmp(c->argv[3]->ptr,"migrating") && c->argc == 5) { + if (server.cluster.slots[slot] != server.cluster.myself) { + addReplyErrorFormat(c,"I'm not the owner of hash slot %u",slot); + return; + } + if ((n = clusterLookupNode(c->argv[4]->ptr)) == NULL) { + addReplyErrorFormat(c,"I don't know about node %s", + (char*)c->argv[4]->ptr); + return; + } + server.cluster.migrating_slots_to[slot] = n; + } else if (!strcasecmp(c->argv[3]->ptr,"importing") && c->argc == 5) { + if (server.cluster.slots[slot] == server.cluster.myself) { + addReplyErrorFormat(c, + "I'm already the owner of hash slot %u",slot); + return; + } + if ((n = clusterLookupNode(c->argv[4]->ptr)) == NULL) { + addReplyErrorFormat(c,"I don't know about node %s", + (char*)c->argv[3]->ptr); + return; + } + server.cluster.importing_slots_from[slot] = n; + } else if (!strcasecmp(c->argv[3]->ptr,"stable") && c->argc == 4) { + /* CLUSTER SETSLOT STABLE */ + server.cluster.importing_slots_from[slot] = NULL; + server.cluster.migrating_slots_to[slot] = NULL; + } else if (!strcasecmp(c->argv[3]->ptr,"node") && c->argc == 4) { + /* CLUSTER SETSLOT NODE */ + clusterNode *n = clusterLookupNode(c->argv[4]->ptr); + + if (!n) addReplyErrorFormat(c,"Unknown node %s", + (char*)c->argv[4]->ptr); + /* If this hash slot was served by 'myself' before to switch + * make sure there are no longer local keys for this hash slot. */ + if (server.cluster.slots[slot] == server.cluster.myself && + n != server.cluster.myself) + { + int numkeys; + robj **keys; + + keys = zmalloc(sizeof(robj*)*1); + numkeys = GetKeysInSlot(slot, keys, 1); + zfree(keys); + if (numkeys == 0) { + addReplyErrorFormat(c, "Can't assign hashslot %d to a different node while I still hold keys for this hash slot.", slot); + return; + } + } + /* If this node was the slot owner and the slot was marked as + * migrating, assigning the slot to another node will clear + * the migratig status. */ + if (server.cluster.slots[slot] == server.cluster.myself && + server.cluster.migrating_slots_to[slot]) + server.cluster.migrating_slots_to[slot] = NULL; + + clusterDelSlot(slot); + clusterAddSlot(n,slot); + } else { + addReplyError(c,"Invalid CLUSTER SETSLOT action or number of arguments"); + return; + } + clusterSaveConfigOrDie(); + addReply(c,shared.ok); } else if (!strcasecmp(c->argv[1]->ptr,"info") && c->argc == 2) { char *statestr[] = {"ok","fail","needhelp"}; int slots_assigned = 0, slots_ok = 0, slots_pfail = 0, slots_fail = 0; @@ -1100,16 +1336,42 @@ void clusterCommand(redisClient *c) { "cluster_slots_ok:%d\r\n" "cluster_slots_pfail:%d\r\n" "cluster_slots_fail:%d\r\n" + "cluster_known_nodes:%lu\r\n" , statestr[server.cluster.state], slots_assigned, slots_ok, slots_pfail, - slots_fail + slots_fail, + dictSize(server.cluster.nodes) ); addReplySds(c,sdscatprintf(sdsempty(),"$%lu\r\n", (unsigned long)sdslen(info))); addReplySds(c,info); addReply(c,shared.crlf); + } else if (!strcasecmp(c->argv[1]->ptr,"keyslot") && c->argc == 3) { + sds key = c->argv[2]->ptr; + + addReplyLongLong(c,keyHashSlot(key,sdslen(key))); + } else if (!strcasecmp(c->argv[1]->ptr,"getkeysinslot") && c->argc == 4) { + long long maxkeys, slot; + unsigned int numkeys, j; + robj **keys; + + if (getLongLongFromObjectOrReply(c,c->argv[2],&slot,NULL) != REDIS_OK) + return; + if (getLongLongFromObjectOrReply(c,c->argv[3],&maxkeys,NULL) != REDIS_OK) + return; + if (slot < 0 || slot >= REDIS_CLUSTER_SLOTS || maxkeys < 0 || + maxkeys > 1024*1024) { + addReplyError(c,"Invalid slot or number of keys"); + return; + } + + keys = zmalloc(sizeof(robj*)*maxkeys); + numkeys = GetKeysInSlot(slot, keys, maxkeys); + addReplyMultiBulkLen(c,numkeys); + for (j = 0; j < numkeys; j++) addReplyBulk(c,keys[j]); + zfree(keys); } else { addReplyError(c,"Wrong CLUSTER subcommand or number of arguments"); } @@ -1410,12 +1672,19 @@ file_rd_err: /* Return the pointer to the cluster node that is able to serve the query * as all the keys belong to hash slots for which the node is in charge. * - * If keys in query spawn multiple nodes NULL is returned. */ -clusterNode *getNodeByQuery(redisClient *c, struct redisCommand *cmd, robj **argv, int argc, int *hashslot) { + * If the returned node should be used only for this request, the *ask + * integer is set to '1', otherwise to '0'. This is used in order to + * let the caller know if we should reply with -MOVED or with -ASK. + * + * If the request contains more than a single key NULL is returned, + * however a request with more then a key argument where the key is always + * the same is valid, like in: RPOPLPUSH mylist mylist.*/ +clusterNode *getNodeByQuery(redisClient *c, struct redisCommand *cmd, robj **argv, int argc, int *hashslot, int *ask) { clusterNode *n = NULL; + robj *firstkey = NULL; multiState *ms, _ms; multiCmd mc; - int i; + int i, slot = 0; /* We handle all the cases as if they were EXEC commands, so we have * a common code path for everything */ @@ -1425,7 +1694,9 @@ clusterNode *getNodeByQuery(redisClient *c, struct redisCommand *cmd, robj **arg if (!(c->flags & REDIS_MULTI)) return server.cluster.myself; ms = &c->mstate; } else { - /* Create a fake Multi State structure, with just one command */ + /* In order to have a single codepath create a fake Multi State + * structure if the client is not in MULTI/EXEC state, this way + * we have a single codepath below. */ ms = &_ms; _ms.commands = &mc; _ms.count = 1; @@ -1434,6 +1705,8 @@ clusterNode *getNodeByQuery(redisClient *c, struct redisCommand *cmd, robj **arg mc.cmd = cmd; } + /* Check that all the keys are the same key, and get the slot and + * node for this key. */ for (i = 0; i < ms->count; i++) { struct redisCommand *mcmd; robj **margv; @@ -1444,26 +1717,50 @@ clusterNode *getNodeByQuery(redisClient *c, struct redisCommand *cmd, robj **arg margv = ms->commands[i].argv; keyindex = getKeysFromCommand(mcmd,margv,margc,&numkeys, - REDIS_GETKEYS_PRELOAD); + REDIS_GETKEYS_ALL); for (j = 0; j < numkeys; j++) { - int slot = keyHashSlot((char*)margv[keyindex[j]]->ptr, - sdslen(margv[keyindex[j]]->ptr)); - struct clusterNode *slotnode; - - slotnode = server.cluster.slots[slot]; - if (hashslot) *hashslot = slot; - /* Node not assigned? (Should never happen actually - * if we reached this function). - * Different node than the previous one? - * Return NULL, the cluster can't serve multi-node requests */ - if (slotnode == NULL || (n && slotnode != n)) { - getKeysFreeResult(keyindex); - return NULL; + if (firstkey == NULL) { + /* This is the first key we see. Check what is the slot + * and node. */ + firstkey = margv[keyindex[j]]; + + slot = keyHashSlot((char*)firstkey->ptr, sdslen(firstkey->ptr)); + n = server.cluster.slots[slot]; + redisAssert(n != NULL); } else { - n = slotnode; + /* If it is not the first key, make sure it is exactly + * the same key as the first we saw. */ + if (!equalStringObjects(firstkey,margv[keyindex[j]])) { + decrRefCount(firstkey); + getKeysFreeResult(keyindex); + return NULL; + } } } getKeysFreeResult(keyindex); } - return (n == NULL) ? server.cluster.myself : n; + if (ask) *ask = 0; /* This is the default. Set to 1 if needed later. */ + /* No key at all in command? then we can serve the request + * without redirections. */ + if (n == NULL) return server.cluster.myself; + if (hashslot) *hashslot = slot; + /* This request is about a slot we are migrating into another instance? + * Then we need to check if we have the key. If we have it we can reply. + * If instead is a new key, we pass the request to the node that is + * receiving the slot. */ + if (n == server.cluster.myself && + server.cluster.migrating_slots_to[slot] != NULL) + { + if (lookupKeyRead(&server.db[0],firstkey) == NULL) { + if (ask) *ask = 1; + return server.cluster.migrating_slots_to[slot]; + } + } + /* Handle the case in which we are receiving this hash slot from + * another instance, so we'll accept the query even if in the table + * it is assigned to a different node. */ + if (server.cluster.importing_slots_from[slot] != NULL) + return server.cluster.myself; + /* It's not a -ASK case. Base case: just return the right node. */ + return n; }