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ruanhaishen
redis
Commits
36676c23
Commit
36676c23
authored
Mar 07, 2014
by
antirez
Browse files
Redis Cluster: support for multi-key operations.
parent
bbf39b7a
Changes
3
Hide whitespace changes
Inline
Side-by-side
src/cluster.c
View file @
36676c23
...
...
@@ -3804,21 +3804,39 @@ void readwriteCommand(redisClient *c) {
}
/* Return the pointer to the cluster node that is able to serve the command.
* For the function to succeed the command should only target a single
* key (or the same key multiple times).
* For the function to succeed the command should only target either:
*
*
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 t
o
*
let the caller know if we should reply with -MOVED or with -ASK
.
*
1) A single key (even multiple times like LPOPRPUSH mylist mylist).
*
2) Multiple keys in the same hash slot, while the slot is stable (n
o
*
resharding in progress)
.
*
* If the command contains multiple keys, and as a consequence it is not
* possible to handle the request in Redis Cluster, NULL is returned. */
clusterNode *getNodeByQuery(redisClient *c, struct redisCommand *cmd, robj **argv, int argc, int *hashslot, int *ask) {
* On success the function returns the node that is able to serve the request.
* If the node is not 'myself' a redirection must be perfomed. The kind of
* redirection is specified setting the integer passed by reference
* 'error_code', which will be set to REDIS_CLUSTER_REDIR_ASK or
* REDIS_CLUSTER_REDIR_MOVED.
*
* When the node is 'myself' 'error_code' is set to REDIS_CLUSTER_REDIR_NONE.
*
* If the command fails NULL is returned, and the reason of the failure is
* provided via 'error_code', which will be set to:
*
* REDIS_CLUSTER_REDIR_CROSS_SLOT if the request contains multiple keys that
* don't belong to the same hash slot.
*
* REDIS_CLUSTER_REDIR_UNSTABLE if the request contains mutliple keys
* belonging to the same slot, but the slot is not stable (in migration or
* importing state, likely because a resharding is in progress). */
clusterNode
*
getNodeByQuery
(
redisClient
*
c
,
struct
redisCommand
*
cmd
,
robj
**
argv
,
int
argc
,
int
*
hashslot
,
int
*
error_code
)
{
clusterNode
*
n
=
NULL
;
robj
*
firstkey
=
NULL
;
int
multiple_keys
=
0
;
multiState
*
ms
,
_ms
;
multiCmd
mc
;
int i, slot = 0;
int
i
,
slot
=
0
,
migrating_slot
=
0
,
importing_slot
=
0
,
missing_keys
=
0
;
/* Set error code optimistically for the base case. */
if
(
error_code
)
*
error_code
=
REDIS_CLUSTER_REDIR_NONE
;
/* We handle all the cases as if they were EXEC commands, so we have
* a common code path for everything */
...
...
@@ -3839,8 +3857,8 @@ 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
. */
/* Check that all the keys are
in
the same
hash
slot
,
and
obtain this
*
slot and the node associated
. */
for
(
i
=
0
;
i
<
ms
->
count
;
i
++
)
{
struct
redisCommand
*
mcmd
;
robj
**
margv
;
...
...
@@ -3853,48 +3871,88 @@ clusterNode *getNodeByQuery(redisClient *c, struct redisCommand *cmd, robj **arg
keyindex
=
getKeysFromCommand
(
mcmd
,
margv
,
margc
,
&
numkeys
,
REDIS_GETKEYS_ALL
);
for
(
j
=
0
;
j
<
numkeys
;
j
++
)
{
robj
*
thiskey
=
margv
[
keyindex
[
j
]];
int
thisslot
=
keyHashSlot
((
char
*
)
thiskey
->
ptr
,
sdslen
(
thiskey
->
ptr
));
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));
firstkey
=
thiskey
;
slot
=
thisslot
;
n
=
server
.
cluster
->
slots
[
slot
];
redisAssertWithInfo
(
c
,
firstkey
,
n
!=
NULL
);
/* If we are migrating or importing this slot, we need to check
* if we have all the keys in the request (the only way we
* can safely serve the request, otherwise we return a TRYAGAIN
* error). To do so we set the importing/migrating state and
* increment a counter for every missing key. */
if
(
n
==
myself
&&
server
.
cluster
->
migrating_slots_to
[
slot
]
!=
NULL
)
{
migrating_slot
=
1
;
}
else
if
(
server
.
cluster
->
importing_slots_from
[
slot
]
!=
NULL
)
{
importing_slot
=
1
;
}
}
else
{
/* 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]])) {
getKeysFreeResult(keyindex);
return NULL;
if
(
!
equalStringObjects
(
firstkey
,
thiskey
))
{
if
(
slot
!=
thisslot
)
{
/* Error: multiple keys from different slots. */
getKeysFreeResult
(
keyindex
);
if
(
error_code
)
*
error_code
=
REDIS_CLUSTER_REDIR_CROSS_SLOT
;
return
NULL
;
}
else
{
/* Flag this request as one with multiple different
* keys. */
multiple_keys
=
1
;
}
}
}
/* Migarting / Improrting slot? Count keys we don't have. */
if
((
migrating_slot
||
importing_slot
)
&&
lookupKeyRead
(
&
server
.
db
[
0
],
thiskey
)
==
NULL
)
{
missing_keys
++
;
}
}
getKeysFreeResult
(
keyindex
);
}
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. */
* without redirections
or errors
. */
if
(
n
==
NULL
)
return
myself
;
/* Return the hashslot by reference. */
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 == 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, but only if the client
* issued an ASKING command before. */
if (server.cluster->importing_slots_from[slot] != NULL &&
(c->flags & REDIS_ASKING || cmd->flags & REDIS_CMD_ASKING)) {
return myself;
* Then if we have all the keys. */
/* If we don't have all the keys and we are migrating the slot, send
* an ASK redirection. */
if
(
migrating_slot
&&
missing_keys
)
{
if
(
error_code
)
*
error_code
=
REDIS_CLUSTER_REDIR_ASK
;
return
server
.
cluster
->
migrating_slots_to
[
slot
];
}
/* If we are receiving the slot, we have all the keys, and the client
* correctly flagged the request as "ASKING", we can serve
* the request, otherwise the only option is to send a TRYAGAIN error. */
if
(
importing_slot
&&
(
c
->
flags
&
REDIS_ASKING
||
cmd
->
flags
&
REDIS_CMD_ASKING
))
{
if
(
missing_keys
)
{
if
(
error_code
)
*
error_code
=
REDIS_CLUSTER_REDIR_UNSTABLE
;
return
NULL
;
}
else
{
return
myself
;
}
}
/* Handle the read-only client case reading from a slave: if this
* node is a slave and the request is about an hash slot our master
* is serving, we can reply without redirection. */
...
...
@@ -3905,6 +3963,9 @@ clusterNode *getNodeByQuery(redisClient *c, struct redisCommand *cmd, robj **arg
{
return
myself
;
}
/* It's not a -ASK case. Base case: just return the right node. */
/* Base case: just return the right node. However if this node is not
* myself, set error_code to MOVED since we need to issue a rediretion. */
if
(
n
!=
myself
&&
error_code
)
*
error_code
=
REDIS_CLUSTER_REDIR_MOVED
;
return
n
;
}
src/cluster.h
View file @
36676c23
...
...
@@ -24,6 +24,13 @@
#define REDIS_CLUSTER_MF_TIMEOUT 5000
/* Milliseconds to do a manual failover. */
#define REDIS_CLUSTER_MF_PAUSE_MULT 2
/* Master pause manual failover mult. */
/* Redirection errors returned by getNodeByQuery(). */
#define REDIS_CLUSTER_REDIR_NONE 0
/* Node can serve the request. */
#define REDIS_CLUSTER_REDIR_CROSS_SLOT 1
/* Keys in different slots. */
#define REDIS_CLUSTER_REDIR_UNSTABLE 2
/* Keys in slot resharding. */
#define REDIS_CLUSTER_REDIR_ASK 3
/* -ASK redirection required. */
#define REDIS_CLUSTER_REDIR_MOVED 4
/* -MOVED redirection required. */
struct
clusterNode
;
/* clusterLink encapsulates everything needed to talk with a remote node. */
...
...
src/redis.c
View file @
36676c23
...
...
@@ -2021,15 +2021,25 @@ int processCommand(redisClient *c) {
addReplySds(c,sdsnew("-CLUSTERDOWN The cluster is down. Use CLUSTER INFO for more information\r\n"));
return REDIS_OK;
} else {
int
ask
;
clusterNode *n = getNodeByQuery(c,c->cmd,c->argv,c->argc,&hashslot,&
ask
);
int
error_code
;
clusterNode *n = getNodeByQuery(c,c->cmd,c->argv,c->argc,&hashslot,&
error_code
);
if (n == NULL) {
addReplyError(c,"Multi keys request invalid in cluster");
if (error_code == REDIS_CLUSTER_REDIR_CROSS_SLOT) {
addReplySds(c,sdsnew("-CROSSSLOT Keys in request don't hash to the same slot\r\n"));
} else if (error_code == REDIS_CLUSTER_REDIR_UNSTABLE) {
/* The request spawns mutliple keys in the same slot,
* but the slot is not "stable" currently as there is
* a migration or import in progress. */
addReplySds(c,sdsnew("-TRYAGAIN Multiple keys request during rehashing of slot\r\n"));
} else {
redisPanic("getNodeByQuery() unknown error.");
}
return REDIS_OK;
} else if (n != server.cluster->myself) {
flagTransaction(c);
addReplySds(c,sdscatprintf(sdsempty(),
"-%s %d %s:%d\r\n", ask ? "ASK" : "MOVED",
"-%s %d %s:%d\r\n",
(error_code == REDIS_CLUSTER_REDIR_ASK) ? "ASK" : "MOVED",
hashslot,n->ip,n->port));
return REDIS_OK;
}
...
...
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