The slowlog command on Azure redis returns the following item in response. What does this command do? It doesn't seem to be a command triggered from the client.
1) (integer) 260
2) (integer) 1660587982
3) (integer) 15508
4) 1) "ManagementCommand"
2) "list"
5) "[::]:31729"
6) ""
ManagementCommand are commands that are triggered by data plane components owned by Azure Cache for Redis for health monitoring purposes there are some Redis commands that return info about the cache itself. The slowlog is an example of this.
Related
I using the go-redis library to check memory usage of a specific key on a Redis cluster.
The library fails sporadically with error "redis: nil" which usually means that it accesses the wrong redis instance to find the key.
The go-redis library is using the Redis CLI: "command" to get the list of arguments for each command, and to find where is the redis key position in the arguments list.
Specifically for the memory CLI, the output of the "command" CLI is:
157) 1) "memory"
2) (integer) -2
3) 1) readonly
2) random
4) (integer) 0
5) (integer) 0
6) (integer) 0
The Redis document: https://redis.io/commands/command
items 4 and 5 are the positions of the first key in arguments, and the last key in arguments.
But the values are zero?
According to the memory CLI document: https://redis.io/commands/memory-usage
The items 4 and 5 should both have the value 3.
Is this a bug in the output of the redis "command" CLI, or am I misunderstanding this?
This is a design issue in redis, see https://github.com/redis/redis/issues/7493
The final action was that a merge of a pull request:
https://github.com/go-redis/redis/pull/1400
I am facing a quite strange issue in our deployment
After certain time in operation
I could not add a particular list with a particular keyname or listname to Redis using RPUSH.
Example
RPUSH client-send-process-servername TEST
I am unable to add that key to Redis database.
Anyways the output after executing that command i get
(Integer) 1
But i could not see the list
redis-cli keys *client-send*
Return empty list
However when this problem appears
I am able successfully execute the following command.
RPUSH client-send-process-ser TEST
And
redis-cli keys *client-send*
NOTE: one ASTRICK before n aftet client-send string
Which is not displayed here
It is listing the Queue
"client-send-process-ser"
However strangely i could not add a List with specific key say
client-send-process-servername
Any ideas to debug further.. where to look and what to look.
Redis Server Version is 2.8
I tired enabling debug logs in redis and tried to use redis-monitor command.
However nothing relevant could be found explaining this issue. I am eager to find a solution. Please if some one could help me to pursue further would be a great help.
It seems that this problem is not reproducible. However I've tested it in my local pc and found that it is working fine.
Example:
➜ ~ redis-cli
127.0.0.1:6379> RPUSH client-send-process-servername TEST
(integer) 1
127.0.0.1:6379> keys *client-send*
1) "client-send-process-servername"
127.0.0.1:6379> keys client-send*
1) "client-send-process-servername"
127.0.0.1:6379> RPUSH client-send-process-ser TEST
(integer) 1
127.0.0.1:6379> keys client-send*
1) "client-send-process-ser"
2) "client-send-process-servername"
127.0.0.1:6379>
If there is any option, you can try updating your redis server. current updated versions is 5.0.7 and yours is 2.8.
I am newbie to Redis and trying to understand concept of Redis PubSub.
Step- 1:
root#01a623a828db:/data# redis-cli -n 1
127.0.0.1:6379[1]> subscribe foo
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "foo"
3) (integer) 1
In 1st step, subscribed database 1
Step- 2:
root#01a623a828db:/data# redis-cli -n 4
127.0.0.1:6379[4]> publish foo 2
(integer) 1
In 2nd step, published message on database 4
Step- 3:
root#01a623a828db:/data# redis-cli -n 1
127.0.0.1:6379[1]> subscribe foo
Reading messages... (press Ctrl-C to quit)
..........................................
1) "message"
2) "foo"
3) "2"
In 3rd step, on database 1 got the message which was published on database 4 in 2nd Step.
I tried to find out the reason behind it but I found same answer everywhere- "Pub/Sub has no relation to the key space. It was made to not interfere with it on any level, including database numbers. Publishing on db 10, will be heard by a subscriber on db 1. If you need scoping of some kind, prefix the channels with the name of the environment (test, staging, production)- This is as per official documentation of Redis PubSub."
Ques-
Why redis pubsub working architecture is independent of database?
How to implement "If you need scoping of some kind, prefix the channels with the name of the environment (test, staging, production)"?
"Publishing on db 10, will be heard by a subscriber on db 1."- It is not inline with statement
It was made to not interfere with it on any level, including database numbers.
it's a matter of design choice really.
If you need scoping, you can always prefix the pattern. eg: pattern productupdate on test env will be watched via test:productupdate and on staging env, it will be staging:productupdate
It seems to inline well with the statement. the database number doesn't matter here.
Instead of storing data into redis, we use redis as our channels to sub/pub. Is this feature redis instance level or for per database?
http://redis.io/topics/pubsub
That is easy enough to test:
Terminal 1: Connect to db 6 and subscribe to foo
> redis-cli -n 6
127.0.0.1:6379[6]> subscribe foo
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "foo"
3) (integer) 1
Terminal 2: Connect to db 1 and publish
> redis-cli -n 1
127.0.0.1:6379[1]> publish foo 2
(integer) 1
127.0.0.1:6379[1]>
Terminal 1: Observe subscriber receiving
1) "message"
2) "foo"
3) "2"
In Redis, keys user* will print all keys starting with user.
For example:
keys user*
1) "user2"
2) "user1"
Now, I want all keys that don't start with user to be printed.
How could I do that?
IMPORTANT: always use SCAN instead of (the evil) KEYS
Redis' pattern matching is somewhat functionally limited (see the implementation of stringmatchlen in util.c) and does not provide that which you seek ATM. That said, consider the following possible routes:
Extend stringmatchlen to match your requirements, possibly submitting it as a PR.
Consider what you're trying to do - fetching a subset of keys is always going to be inefficient unless you index them, consider tracking the names of all non-user keys (i.e.g. in a Redis Set) instead.
If you are really insistent on scanning the entire keyspace and match against negative patterns, one way to accomplish that is with a little bit of Lua magic.
Consider the following dataset and script:
127.0.0.1:6379> dbsize
(integer) 0
127.0.0.1:6379> set user:1 1
OK
127.0.0.1:6379> set use:the:force luke
OK
127.0.0.1:6379> set non:user a
OK
Lua (save this as scanregex.lua):
local re = ARGV[1]
local nt = ARGV[2]
local cur = 0
local rep = {}
local tmp
if not re then
re = ".*"
end
repeat
tmp = redis.call("SCAN", cur, "MATCH", "*")
cur = tonumber(tmp[1])
if tmp[2] then
for k, v in pairs(tmp[2]) do
local fi = v:find(re)
if (fi and not nt) or (not fi and nt) then
rep[#rep+1] = v
end
end
end
until cur == 0
return rep
Output - first time regular matching, 2nd time the complement:
foo#bar:~$ redis-cli --eval scanregex.lua , "^user"
1) "user:1"
foo#bar:~$ redis-cli --eval scanregex.lua , "^user" 1
1) "use:the:force"
2) "non:user"
#Karthikeyan Gopall you nailed it in your comment above and this saved me a bunch of time. Thanks!
Here's how you can use it in various combinations to get what you want:
redis.domain.com:6379[1]> set "hello" "foo"
OK
redis.domain.com:6379[1]> set "hillo" "bar"
OK
redis.domain.com:6379[1]> set "user" "baz"
OK
redis.domain.com:6379[1]> set "zillo" "bash"
OK
redis.domain.com:6379[1]> scan 0
1) "0"
2) 1) "zillo"
2) "hello"
3) "user"
4) "hillo"
redis.domain.com:6379[1]> scan 0 match "[^u]*"
1) "0"
2) 1) "zillo"
2) "hello"
3) "hillo"
redis.domain.com:6379[1]> scan 0 match "[^u^z]*"
1) "0"
2) 1) "hello"
2) "hillo"
redis.domain.com:6379[1]> scan 0 match "h[^i]*"
1) "0"
2) 1) "hello"
According to redis keys documentation the command supports glob style patterns, not regular expressions.
and if you look at the documentation, you'll see that the "!" character is not special as opposites to regular expressions.
Here is a simple test I ran in my own db:
redis 127.0.0.1:6379> set a 0
OK
redis 127.0.0.1:6379> set b 1
OK
redis 127.0.0.1:6379> keys *
1) "a"
2) "b"
redis 127.0.0.1:6379> keys !a
(empty list or set) // I expected "b" here
redis 127.0.0.1:6379> keys !b
(empty list or set) // I expected "a" here
redis 127.0.0.1:6379> keys [!b]
1) "b"
redis 127.0.0.1:6379> keys [b]
1) "b"
redis 127.0.0.1:6379> keys [ab]
1) "a"
2) "b"
redis 127.0.0.1:6379> keys ![b]
(empty list or set)
So I just don't think what you are trying to achieve is possible via the keys command.
Besides, the keys command is not very suitable for production environment as it locks your whole redis database.
I would recommend getting all the keys with the scan command, store them locally, and then remove them using LUA
Here's a trick to achieve this with native redis commands (no need for Lua scripts or anything).
If you are able to control the timing of when you insert the new keys (the ones you want to keep, deleting all other stuff like in your question), you can:
Before setting the new keys, set the expiration to all existing keys (by pattern or everything) to expire right now (see how)
Load the new keys
Redis will automatically delete all the older keys and you will be left just with the new ones you want.
You also can print all keys and pass it to grep. For example:
redis-cli -a <password> keys "*" | grep -v "user"