There’s no command for that, but you can write a script to do so. You will need to perform for each key a “type” command: > type <key> and depending on the response perform: for “string”: get <key> for “hash”: hgetall <key> for “list”: lrange <key> 0 -1 for “set”: smembers <key> for “zset”: zrange … Read more
First, lets talk sentinel. Sentinel manages the failover, it doesn’t configure Redis for HA. It is an important distinction. Second, the diagram you posted is actually a bad setup – you don’t want to run Sentinel on the same node as the Redis nodes it is managing. When you lose that host you lose both. … Read more
Redis pub-sub is mostly like a fire and forget system where all the messages you produced will be delivered to all the consumers at once and the data is kept nowhere. You have limitation in memory with respect to Redis. Also, the number of producers and consumers can affect the performance in Redis. Kafka, on … Read more
The key you’re talking about using isn’t really all that long. The example key you give is for a set, set lookup methods are O(1). The more complex operations on a set (SDIFF, SUNION, SINTER) are O(N). Chances are that populating $userId was a more expensive operation than using a longer key. Redis comes with … Read more
I can’t seem to figure out when it’s time to use it in an application. I would recommend you to read this tutorial which contains also use cases. Since redis is rather memory oriented it’s really good for frequently updated real-time data, such as session store, state database, statistics, caching and its advanced data structures … Read more
I suggest you read about this on http://redis.io/topics/persistence . Basically you lose the guaranteed persistence when you increase performance by using only in-memory storing. Imagine a scenario where you INSERT into memory, but before it gets persisted to disk lose power. There will be data loss. Redis supports so-called “snapshots”. This means that it will … Read more
You can issue the INFO command, which returns information and statistics about the server. See here for an example output. As mentioned in the comments by mVChr, you can use info keyspace directly on the redis-cli. redis> INFO # Server redis_version:6.0.6 redis_git_sha1:00000000 redis_git_dirty:0 redis_build_id:b63575307aaffe0a redis_mode:standalone os:Linux 5.4.0-1017-aws x86_64 arch_bits:64 multiplexing_api:epoll atomicvar_api:atomic-builtin gcc_version:9.3.0 process_id:2854672 run_id:90a5246f10e0aeb6b02cc2765b485d841ffc924e tcp_port:6379 … Read more
redis-cli -h XXX.XXX.XXX.XXX -p YYYY xxx.xxx.xxx.xxx is the IP address and yyyy is the port EXAMPLE from my dev environment redis-cli -h 10.144.62.3 -p 30000 REDIS CLI COMMANDS Host, port, password and database By default redis-cli connects to the server at 127.0.0.1 port 6379. As you can guess, you can easily change this using command … Read more
After installing redis, type from terminal: redis-server And Redis-Server will be started
You don’t want to use multiple databases in a single redis instance. As you noted, multiple instances lets you take advantage of multiple cores. If you use database selection you will have to refactor when upgrading. Monitoring and managing multiple instances is not difficult nor painful. Indeed, you would get far better metrics on each … Read more