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redis-cli: try to make clusterManagerFixOpenSlot() more readable.

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Also improve the message to make clear that there is no *clear* owner,
not that there is no owner at all.
This commit is contained in:
antirez 2020-04-29 12:37:12 +02:00
parent 1a5c3a9a60
commit 86a1386d6f
1 changed files with 25 additions and 6 deletions
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31
src/redis-cli.c
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@ -4596,20 +4596,26 @@ static int clusterManagerFixOpenSlot(int slot) {
/* Try to obtain the current slot owner, according to the current
* nodes configuration. */
int success = 1;
list *owners = listCreate();
list *owners = listCreate(); /* List of nodes claiming some ownership.
it could be stating in the configuration
to have the node ownership, or just
holding keys for such slot. */
list *migrating = listCreate();
list *importing = listCreate();
sds migrating_str = sdsempty();
sds importing_str = sdsempty();
clusterManagerNode *owner = NULL;
clusterManagerNode *owner = NULL; /* The obvious slot owner if any. */
/* Iterate all the nodes, looking for potential owners of this slot. */
listIter li;
listNode *ln;
listRewind(cluster_manager.nodes, &li);
while ((ln = listNext(&li)) != NULL) {
clusterManagerNode *n = ln->value;
if (n->flags & CLUSTER_MANAGER_FLAG_SLAVE) continue;
if (n->slots[slot]) listAddNodeTail(owners, n);
else {
if (n->slots[slot]) {
listAddNodeTail(owners, n);
} else {
redisReply *r = CLUSTER_MANAGER_COMMAND(n,
"CLUSTER COUNTKEYSINSLOT %d", slot);
success = clusterManagerCheckRedisReply(n, r, NULL);
@ -4623,7 +4629,14 @@ static int clusterManagerFixOpenSlot(int slot) {
if (!success) goto cleanup;
}
}
/* If we have only a single potential owner for this slot,
* set it as "owner". */
if (listLength(owners) == 1) owner = listFirst(owners)->value;
/* Scan the list of nodes again, in order to populate the
* list of nodes in importing or migrating state for
* this slot. */
listRewind(cluster_manager.nodes, &li);
while ((ln = listNext(&li)) != NULL) {
clusterManagerNode *n = ln->value;
@ -4655,6 +4668,7 @@ static int clusterManagerFixOpenSlot(int slot) {
}
}
}
/* If the node is neither migrating nor importing and it's not
* the owner, then is added to the importing list in case
* it has keys in the slot. */
@ -4679,11 +4693,12 @@ static int clusterManagerFixOpenSlot(int slot) {
printf("Set as migrating in: %s\n", migrating_str);
if (sdslen(importing_str) > 0)
printf("Set as importing in: %s\n", importing_str);
/* If there is no slot owner, set as owner the node with the biggest
* number of keys, among the set of migrating / importing nodes. */
if (owner == NULL) {
clusterManagerLogInfo(">>> Nobody claims ownership, "
"selecting an owner...\n");
clusterManagerLogInfo(">>> No single clear owner for the slot, "
"selecting an owner by # of keys...\n");
owner = clusterManagerGetNodeWithMostKeysInSlot(cluster_manager.nodes,
slot, NULL);
// If we still don't have an owner, we can't fix it.
@ -4714,6 +4729,7 @@ static int clusterManagerFixOpenSlot(int slot) {
clusterManagerRemoveNodeFromList(migrating, owner);
clusterManagerRemoveNodeFromList(importing, owner);
}
/* If there are multiple owners of the slot, we need to fix it
* so that a single node is the owner and all the other nodes
* are in importing state. Later the fix can be handled by one
@ -4746,6 +4762,7 @@ static int clusterManagerFixOpenSlot(int slot) {
}
}
int move_opts = CLUSTER_MANAGER_OPT_VERBOSE;
/* Case 1: The slot is in migrating state in one node, and in
* importing state in 1 node. That's trivial to address. */
if (listLength(migrating) == 1 && listLength(importing) == 1) {
@ -4757,6 +4774,7 @@ static int clusterManagerFixOpenSlot(int slot) {
move_opts |= CLUSTER_MANAGER_OPT_UPDATE;
success = clusterManagerMoveSlot(src, dst, slot, move_opts, NULL);
}
/* Case 2: There are multiple nodes that claim the slot as importing,
* they probably got keys about the slot after a restart so opened
* the slot. In this case we just move all the keys to the owner
@ -4787,6 +4805,7 @@ static int clusterManagerFixOpenSlot(int slot) {
if (!success) goto cleanup;
}
}
/* Case 3: The slot is in migrating state in one node but multiple
* other nodes claim to be in importing state and don't have any key in
* the slot. We search for the importing node having the same ID as