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How to query all key-value pairs for a pattern from Redis without making multiple requests

I’m trying to get all the key value pairs for a given prefix from Redis, without making many network requests using Rust. The answers so far suggest using bash or making multiple requests.

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  1. Chosen as BEST ANSWER
    0

    The best method I've found is to use a lua script to construct the response. The example below is not the fastest since we can use EVALSHA to reduce our request size.

    Code:

    let raw_kv: Vec<Option<(String, Vec<u8>)>> = tokio::time::timeout(
    timeout,
    redis::cmd("EVAL")
        .arg(
            // use KEYS instead of SCAN since EVAL is already blocking
            "
    local keys = redis.call('KEYS', ARGV[1]);
    if next(keys) == nil then return keys end;
    local out = {};
    for i=1,#keys do out[i] = {keys[i], redis.call('GET', keys[i])} end
    return out;
    ",
        )
        .arg(0) // no manually passed in keys
        .arg(pattern) // custom pattern to search for
        .query_async(&mut self.conn),
)
.await;

    Docs: https://docs.rs/redis/latest/redis/struct.Cmd.html#method.arg


  2. 0

    The bottom line is that Redis doesn’t do this. You can get all the keys for a pattern using the KEYS or SCAN commands. Then you can GET the keys that are returned. And you can write a Lua script or use JavaScript to write a function to do this for you.

    However, this is neither very convenient nor is it particularly fast, especially if you have a lot of data. And, the KEYS command is problematic as it block the main Redis thread while it runs. Furthermore, if you are running a cluster, this gets more complex as the keys you want to find are going to be on multiple servers.

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