CODEWITHSUNDEEP
redis
Yoav Cohen
Yoav Cohen

Reputation: 92

Redis keyspace notifications - get values(small size) of set operations

I'm working on creating DB with Redis.

One of my recruitments is that all the clients in the system will be able to listen to set events and get information about both key and value change.

I know that publishing value may be big(512 MB) but I know that in my system the size of value will not be more than 100 chars.

I have 3 possible solutions and I wonder which one will be better or consider other solutions:

1) After each set operation client will also publish it (PUB/SUB)

2)Edit setGenericCommand function to publish the value as well and use keyspace binding.

3)After client receive keyspace notification it will get the value with get operation.

I would like to understand which approach will be better? Thank you!

Upvotes: 0

Views: 864

Answers (1)

Itamar Haber
Itamar Haber

Reputation: 49942

So, 1st and foremost, remember that PubSub is at-most-once delivery. If you really need to process every change in the client, you should consider a more resilient way to do so.

That said, assuming you're ok with PubSub's promises, 1 is the simplest and I'd go with that. At most, I'd provide the clients with a Lua wrapper that combines the SET and PUBLISH commands. This, of course, removes the need to actually listen to Keyspace notifications as you basically implementing it yourself.

2 means hacking Redis, which is great but means you'll have to maintain your own which is meh--;

3 is also simple enough, but with 1 you get away with a single round trip instead of 2.

Another (4) approach is to write a custom module, but IMO too complex for this need. Go with 1 and Lua, and may the force be with you.

Upvotes: 2

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