LOADING Redis is loading the dataset in memory (Redis::CommandError)

/usr/local/bundle/gems/redis-4.1.4/lib/redis/client.rb:126:in `call': LOADING Redis is loading the dataset in memory (Redis::CommandError)

This really means Redis is still loading data. If Redis is running in --append-only mode, database file (appendonly.aof) will only get larger until it has couple of gigabytes or more and takes couple of minutes to load.

Needs to be compacted regularly, to get rid of old data.

redis-cli
127.0.0.1:6379> BGREWRITEAOF
Background append only file rewriting started

It will compact couple of gigabytes into couple of megabytes. For Rails app.