Lua脚本从Redis HGETALL调用返回高效字典 [英] Lua script to return efficient dictionary from Redis HGETALL call

问题描述

我需要从 Lua 脚本中使用 Redis HMGET 并在以下代码中提取特定值.但是 redis.call('HMGET', table_key, hkey1, hkey2, ...) 返回一个平面数组 {hkey1, val1, hkey2, val2, ...}

I need to use Redis HMGET from a Lua script and extract specific values in following code. But redis.call('HMGET', table_key, hkey1, hkey2, ...) return a flat array of {hkey1, val1, hkey2, val2, ...}

通过我写的键提取值:

local function flat_map_get(flat_map, hash_key)
    local i = 1
    while flat_map[i] do
        if flat_map[i] == hash_key then
            return flat_map[i+1]
        end
        i = i+2
    end
end

当然，随着使用量的增长，多次调用此函数会导致性能大幅下降.

Of course, as usage grow, multiple calls to this function presented major performance drop.

从 HMGET 返回的平面数组中读取值的有效方法是什么?或者以其他方式将返回值转换为正确的键值表?

What is an efficient way to read values from the flat array returned by HMGET? Or otherwise, to convert the returned value into a proper key-value table?

推荐答案

经过一些分析和测试，我们发现以下函数具有良好的性能，并使用它来获得合适的表.

After some profiling and tests, we found the following function to have good performance and use it to get a proper table.

这样就无需为每个哈希键检索调用 getter 函数.

This save the need to call a getter function for each hash key retrieval.

local function hgetall(hash_key)
    local flat_map = redis.call('HGETALL', hash_key)
    local result = {}
    for i = 1, #flat_map, 2 do
        result[flat_map[i]] = flat_map[i + 1]
    end
    return result
end

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