lua - 如何在 Lua 脚本中使用 SMEMBERS 的结果作为 SUNION 的输入

Question

我正在尝试生成一个 Lua 脚本，该脚本采用集合的成员(每个成员也代表一个集合)并返回并集。 这是这 3 组的具体示例:

smembers u:1:skt:n1
1) "s2"
2) "s3"
3) "s1"

smembers u:1:skt:n2
1) "s4"
2) "s5"
3) "s6"

smembers u:1:skts
1) "u:1:skt:n1"
2) "u:1:skt:n2"

所以集合u:1:skts包含其他2个集合的引用，并且我 想要生成 u:1:skt:n1 和 u:1:skt:n2 的并集，如下所示:

1) "s1"
2) "s2"
3) "s3"
4) "s4"
5) "s5"
6) "s6"

这是我到目前为止所拥有的:

local indexes = redis.call("smembers", KEYS[1])
return redis.call("sunion", indexes)

但我收到以下错误:

(error) ERR Error running script (call to f_c4d338bdf036fbb9f77e5ea42880dc185d57ede4): 
@user_script:1: @user_script: 1: Lua redis() command arguments must be strings or integers

它似乎不喜欢将 indexes 变量作为 sunion 命令的输入。有什么想法吗？

Answer 1

请勿执行此操作，否则您将无法迁移到集群。这是来自documentation :

All Redis commands must be analyzed before execution to determine which keys the command will operate on. In order for this to be true for EVAL, keys must be passed explicitly. This is useful in many ways, but especially to make sure Redis Cluster can forward your request to the appropriate cluster node.

Note this rule is not enforced in order to provide the user with opportunities to abuse the Redis single instance configuration, at the cost of writing scripts not compatible with Redis Cluster.

如果你仍然决定违反规则，请使用Lua的unpack :

local indexes = redis.call("smembers", KEYS[1])
return redis.call("sunion", unpack(indexes))