CODEWITHSUNDEEP
redislua
user27111987
user27111987

Reputation: 1085

Redis multiple calls vs lua script

I have the below use case.

Basically, I am trying to do a set with nx and get. Here is the lua script I came up with

local v = redis.call('GET', KEYS[1])
if v then
     return v
end
redis.call('SETEX', KEYS[1], ARGV[1], ARGV[2])"

I am slightly confused whether I should use the above Lua script as compared to executing two different separate commands of get first and then set.

Any pros or cons of using the lua script. Or should two separate commands be better.

Upvotes: 3

Views: 910

Answers (1)

Kevin Christopher Henry
Kevin Christopher Henry

Reputation: 48922

Yes, you should use the script.

If you use two separate Redis commands then you'll end up with a race condition: another process might set the value after your GET and before your SETEX, causing you to overwrite it. Your logic requires this sequence of commands to be atomic, and the best way to do that in Redis is with a Lua script.

It would be possible to achieve this without the script, by using MULTI and WATCH, but the Lua script is much more straightforward.

Upvotes: 3

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