I mean is there a command used to check whether a redis command is readonly?
is_readonly(command)
It will better if there is command in Jedis.
with COMMAND you can get list of all commands with command flags such as
readonly
so here's the list I've end up with:
publish bgsave sunion readonly exists hstrlen lindex scan ping latency ttl wait zscore zrevrangebylex sscan geohash getbit hkeys zrange monitor llen save auth zcard shutdown sync dbsize subscribe zrangebylex zlexcount mget getrange bitpos config lrange replconf discard asking client pfselftest bgrewriteaof unsubscribe zrank readwrite hget bitcount randomkey time zrevrank sinter dump strlen unwatch smembers georadius lastsave slowlog sismember hexists multi sdiff geopos hscan script keys hvals pfcount zscan echo command select zcount substr pttl hlen info scard geodist srandmember hgetall cluster psync pubsub psubscribe zrevrange hmget object watch zrangebyscore get type zrevrangebyscore punsubscribe georadiusbymember
though you might want to exclude readonly admin commands - they don't change data but can cause side effects. here's list with excluded admin:
publish sunion readonly exists hstrlen lindex scan ping ttl wait zscore zrevrangebylex sscan geohash getbit hkeys zrange llen auth zcard dbsize subscribe zrangebylex zlexcount mget getrange bitpos lrange discard asking client pfselftest unsubscribe zrank readwrite hget bitcount randomkey time zrevrank sinter dump strlen unwatch smembers georadius lastsave slowlog sismember hexists multi sdiff geopos hscan script keys hvals pfcount zscan echo command select zcount substr pttl hlen info scard geodist srandmember hgetall pubsub psubscribe zrevrange hmget object watch zrangebyscore get type zrevrangebyscore punsubscribe georadiusbymember
more here: http://redis.io/commands/command#examples
I think you might also check which commands is available for specific redis server version.
Related
When I scan entire redis instance using redis-cli --bigkeys following shortened result is returned
-------- summary -------
Sampled 241145 keys in the keyspace!
Total key length in bytes is 13013217 (avg len 53.96)
Biggest string found 'celery-task-meta-52b14b66-b924-4c40-b7dc-7d5b9b633470' has 6510 bytes
**Biggest list found 'celery9' has 156519 items**
Biggest set found '_kombu.binding.celeryev' has 52 members
Biggest hash found 'unacked' has 544 fields
Biggest zset found 'unacked_index' has 550 members
As you can see my biggest list is celery9 with length 156519. I am using only one keyspace
127.0.0.1:6379> info keyspace
# Keyspace
db0:keys=256672,expires=256659,avg_ttl=1701804
But when I connect to redis instance using redis-cli or even with redis connector from python and run following commands
127.0.0.1:6379> get celery9
(nil)
127.0.0.1:6379> llen celery9
(integer) 0
127.0.0.1:6379>
nil or zero is returned as if there was no key celery9.
So the question is, how to get correct length of this key? All others keys are working perfectly
I want to see the List of queues in the Redis server using Redis-cli. I am using this command to just monitor the queue.
redis-cli MONITOR | grep queuename
Please tell me if we have the any cli comamnd which meet my requirement.
I don't seem to have enough reputation to clarify in a comment how you have implemented your queue, so I'll provide a few thoughts below assuming you have your queue implemented as a FIFO queue using RPUSH and LPOP to add and remove items from your queue.
> RPUSH queue-1 "task-a"
(integer) 1
>LPOP queue-1
"task-a"
If you use a standard naming convention for your lists that represent queues, you could get them by name from the KEYS command with something like KEYS queue-*. A couple of notes on this approach. First, this has some performance concerns if you have a large number of keys in your production instance the best use is for ad-hoc troubleshooting when the rest of your team is aware there may be some performance hit to your redis instance. Second, this will only show keys where the list contains elements. If you have drained a queue it will not appear in the returned values.
An alternative using sorted sets to hold the keys for the lists used as queues, and modifying the score associated with the queue to give you an idea of the queue size. When adding or removing a message to a queue, you would also use ZADD to increment the score by the number of elements added or returned. This would allow you to quickly get the set of lists used as queues by decreasing queue size with ZREVRANGE at any point.
> RPUSH queue-1 "task-a"
(integer) 1
> ZADD queues INCR 1 queue-1
"1"
> RPUSH queue-1 "task-b"
(integer) 2
> ZADD queues INCR 1 queue-1
"2"
> RPUSH queue-2 "message-a"
(integer) 1
> ZADD queues INCR 1 queue-2
"1"
> RPUSH queue-2 "message-b"
(integer) 2
> ZADD queues INCR 1 queue-2
"2"
> LPOP queue-2
"message-a"
> ZADD queues INCR -1 queue-2
"1"
> ZREVRANGE queues 0 -1 WITHSCORES
1) "queue-1"
2) "2"
3) "queue-2"
4) "1"
I'm new to Redis so this will be a rudimentary question.
I'm considering creating a Redis job queue using a list. The jobs themselves will be JSON-encoded objects.
I realize that I can use LPOP and RPUSH for managing the queue. I can even use RPOPLPUSH when using multiple lists (e.g "Queued", "Processing" and "Completed").
Let's say I have a worker that processes images by steadily going through the "Queued" list. Then let's say the client has deleted an image from the front-end, before that particular job has even begun to process. How do I delete this job from the "Queued" list so the worker doesn't waste time processing it?
In other words, how can I index individual jobs in a job queue?
use a sorted set with the timestamp as the score and you can remove a job
$ redis-cli zadd myjobs `date +"%s.%N"` job1
$ redis-cli zadd myjobs `date +"%s.%N"` job2
$ redis-cli zadd myjobs `date +"%s.%N"` job3
$ redis-cli
127.0.0.1:6379> ZRANGEBYSCORE myjobs -inf +inf WITHSCORES
1) "job1"
2) "1638908693.1293526"
3) "job2"
4) "1638908696.5061705"
5) "job3"
6) "1638908699.2742543"
127.0.0.1:6379> ZREMRANGEBYLEX myjobs [job2 [job2
(integer) 1
127.0.0.1:6379> ZRANGEBYSCORE myjobs -inf +inf WITHSCORES
1) "job1"
2) "1638908693.1293526"
3) "job3"
4) "1638908699.2742543"
redis 127.0.0.1:6379> zadd somekey 12.54 value
(integer) 1
redis 127.0.0.1:6379> zrevrange somekey 0 -1 withscores
1) "value"
2) "12.539999999999999"
How do I keep the original number format in redis?
Redis relies on client for number precision conversion, so this might not be possible to achieve using Redis default cli using python.
A similar thread for same :
http://www.manning-sandbox.com/thread.jspa?messageID=159190
How do I copy a sorted set in redis to a regular, unsorted set? Is there a redis command that can do this? I can manually iterate through the sorted set and manually insert in the unsorted set, but it seems like there might be a better way to do this.
I don't think there is any command to do this directly.
But you can write simple lua script to do it on server instead downloading the sorted sets content to client and then pushing it back to new set.
Redis commands:
SCRIPT LOAD "for i,v in ipairs(redis.call('zrange', KEYS[1], 0, -1)) do redis.call('sadd', KEYS[2], v) end"
ZADD zset 1 first
ZADD zset 2 second
ZADD zset 3 third
EVALSHA dd1c22a22108d758b93c26eb92d1ef2933cec314 2 zset set
SMEMBERS set
Result:
"dd1c22a22108d758b93c26eb92d1ef2933cec314"
(integer) 0
(integer) 0
(integer) 0
(nil)
1) "second"
2) "first"
3) "third"
SCRIPT LOAD defines the script and returns its sha hash, EVALSHA than executes. Arguments are 2 to indicate that 2 key names follows, first is sorted set to copy from, second is set to copy to.