Rails Redis Reset Counters to 0

Question

I would like to reset the value of a REDIS counter to 0 in a Rails 4 app.

I use hincrby to increment counters

 $redis.hincrby("user:likes", "key", 1)

I can't delete the key with hdel http://redis.io/commands/hdel because I need to get the key often.

GETSET is atomic and could do the job http://redis.io/commands/getset, as in the example

 GETSET mycounter "0"

But since I use hashes I need to use HSET http://redis.io/commands/hset

$redis.hset("user:likes", "key", "0")

It's not specified if hset is atomic, anyone used hset to reset redis counters to 0? If it's not a good option to reset a counter to 0, any idea how to do it?

Not sure I understand. If you need to set it to zero, set it to zero. Or are you saying you really need GETSET functionality, but for the hash? — Philip Hallstrom
It's specified in the docs that GETSET is atomic but it's not specified for HSET, so is HSET atomic? — stefano_cdn
I don't know, but GETSET is two operations. HSET is one, so I imagine would be atomic, no? — Philip Hallstrom

Vincent Vincent · Accepted Answer · 2016-01-19T19:20:09

It is atomic, so if you run $redis.hset("user:likes", "key", "0"), it doesn't affect other fields inside the "user:likes" hash besides the field: "key"

Rails Redis Reset Counters to 0

1 Answers