What is the best way to batch get on keys in Redis Cluster in response to a batch API?

4
votes

I'm using redis hashes to store metadata associated with a single key which in my case is userId. I have a batchAPI where I pass in a batch of userIds and get the metadata back. Redis Cluster doesn't support multi key commands so What's the best way to achieve this with RedisCluster? I am using Jedis as the Java Client to connect to Redis.

1
redisjedis
You can arrange for a user meta data hash to be stored in the same hash slot as the user's key with hashtags. If the metadata is on a different slot and/or multiple users are across multiple slots, you'll have to fetch the data separately from each shard and handle MOVED messages. I'm not sure whether Jedis does that for you on the fly or for batches (?) but you can try asking its mailing list: groups.google.com/forum/#!forum/jedis_redis - Itamar Haber

1 Answers

4
votes

If Lettuce is an option for you, then from 4.0.Final MGET on cluster is supported:

The cluster API was extended to run a command on multiple nodes and invocation to multi-key commands DEL, MGET, MSET and MSETNX perform automatic pipelining if the keys belong to different slots/masters.

(Source: https://github.com/mp911de/lettuce/releases/tag/4.0.Final)