Want to perform cross slot operations

[Sabyasachi Sahoo]

Hello,
I want to perform some cross slot operations.
When I explored, I found that a flag(allow-cross-slot-keys) was added in this PR - https://github.com/redis/redis-doc/pull/1893/files. 
I tried to apply this flag in script as well as function but no luck.
I am trying to do this via java app. 
redis version - 7.0.11

client library - lettuce.

I'm stuck for quite sometime now
Please help, thanks in advance.

Thanks and Regards,
Sabya

[Sotto Voce]

You mention "script" and "function", but it's not clear whether you're talking about LUA scripts/functions invoked by the EVAL/FCALL commands, or you're talking about ordinary key read and write commands.  Are you working with LUA scripts or functions?

[Sabyasachi Sahoo]

Hello Sotto,
I am talking about Lua Script and Functions

#!lua flags=allow_cross_slot_keys
local function add_user(keys, user_code, parent_code)
    local exists = redis.call('EXISTS', parent_code)

    if exists == 1 then
        redis.call('SADD', parent_code .. ':children', user_code)
        redis.call('INCR', parent_code .. ':version')
        redis.call('SET', user_code, parent_code)
        redis.call('SET', user_code .. ':version', '1')
    end

    return true
end

redis.register_function{
    function_name = 'add_user',
    callback = add_user,
    flags = { 'allow-cross-slot-keys' }
}

here parent_code and user_code are in different slots.

Regards,
Sabya

[Madelyn Olson]

Using scripts that cross slots is considered an anti-pattern in Redis. The flag you mentioned is mostly intended for compatibility with older scripts which might have been previously accessing cross slots, see https://redis.io/docs/manual/programmability/lua-api/#script_flags. You should investigate if you can modify  your script to use hash tags to follow best practices.

-Madelyn

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[Sabyasachi Sahoo]

ERR Unexpected flag in script shebang: allow_cross_slot_keys
when I am trying to load the script that I have pasted via redis-cli , it is throwing this - ERR Unexpected flag in script shebang: allow_cross_slot_keys , when i 'm trying to load it via java code and use it , then i am getting cross slot error.

My use case is that , i can't keep parent and child both in same slot.

Please help. Provide some examples 

Thanks and Regards,
Sabya

[Itamar Haber]

Hello Sabya,

Please make sure that you use the correct flag.

The example and errors you've shared indicate that you're using an unknown flag, namely "allow_cross_slot_keys".

Per the documentation at https://redis.io/docs/manual/programmability/lua-api/#register-function, the flag's correct form is "allow-cross-slot-keys".

Cheers

Itamar

[Viktor Söderqvist]

Hello Sabya,

> My use case is that , i can't keep parent and child both in same slot.

I'm curious, how can you be sure these slots are on the same Redis node?
Are you using Cluster with only one shard?

Viktor

On 2023-06-12 08:38, Sabyasachi Sahoo wrote:
> ERR Unexpected flag in script shebang: allow_cross_slot_keys
> when I am trying to load the script that I have pasted via redis-cli ,

> it is throwing this - *ERR Unexpected flag in script shebang:
> allow_cross_slot_keys *, when i 'm trying to load it via java code and

> use it , then i am getting cross slot error.
>
> My use case is that , i can't keep parent and child both in same slot.
>
> Please help. Provide some examples
>
> Thanks and Regards,
> Sabya
>
> On Saturday, June 10, 2023 at 10:11:01 PM UTC+5:30 madely...@gmail.com
> wrote:
>
> Using scripts that cross slots is considered an anti-pattern in
> Redis. The flag you mentioned is mostly intended for compatibility
> with older scripts which might have been previously accessing cross
> slots, see
> https://redis.io/docs/manual/programmability/lua-api/#script_flags

> <https://redis.io/docs/manual/programmability/lua-api/#script_flags>. You should investigate if you can modify  your script to use hash tags to follow best practices.

>
> -Madelyn
> On Jun 8, 2023 at 8:50 PM -0700, Sotto Voce <speakso...@gmail.com>,
> wrote:
>> You mention "script" and "function", but it's not clear whether
>> you're talking about LUA scripts/functions invoked by the
>> EVAL/FCALL commands, or you're talking about ordinary key read and
>> write commands.  Are you working with LUA scripts or functions?
>>
>> On Thursday, June 8, 2023 at 6:00:34 AM UTC-7 Sabyasachi Sahoo wrote:
>>
>> Hello,
>> I want to perform some cross slot operations.
>> When I explored, I found that a flag(allow-cross-slot-keys)
>> was added in this PR -
>> https://github.com/redis/redis-doc/pull/1893/files

>> <https://github.com/redis/redis-doc/pull/1893/files>.

>> I tried to apply this flag in script as well as function but
>> no luck.
>> I am trying to do this via java app.
>> redis version - 7.0.11
>> client library - lettuce.
>>
>> I'm stuck for quite sometime now
>> Please help, thanks in advance.
>>
>> Thanks and Regards,
>> Sabya
>>
>> --
>> You received this message because you are subscribed to the Google
>> Groups "Redis DB" group.
>> To unsubscribe from this group and stop receiving emails from it,
>> send an email to redis-db+u...@googlegroups.com.
>> To view this discussion on the web visit

>> https://groups.google.com/d/msgid/redis-db/dc61a882-7a21-4ab9-978b-8638bda1d531n%40googlegroups.com <https://groups.google.com/d/msgid/redis-db/dc61a882-7a21-4ab9-978b-8638bda1d531n%40googlegroups.com?utm_medium=email&utm_source=footer>.

>
> --
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