How to Remove Multiple Redis Cache

Goals

Remove multiple Redis cache key using one liner command.

Steps

Assume keys that we want to delete are keys beginning with 'laravel:' prefix.

$ redis-cli KEYS 'laravel:*'
1) "laravel:featured:2bf46b40ed15"
2) "laravel:list:5509f57fdaef"
3) "laravel:list:2bf46b40ed15"
4) "laravel:list:e1bf5bfc2ab8"
5) "laravel:list-total-rec:adc81409d693"
6) "laravel:list-total-rec:e1bf5bfc2ab8"
7) "laravel:promotion-list:adc81409d693"
8) "laravel:list:d1f68333e3bb"
9) "laravel:list:c6a45c5cf5c5"

Just pipe the output above to xargs command. By default redis-cli will use raw format when STDOUT is not tty, which in case is true for xargs.

$ redis-cli KEYS 'laravel:*' | xargs redis-cli DEL
(integer) 9

Reference

• https://redis.io/commands/

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Redis: How to Increase File Descriptor Limits

Problem

When you run redis server it complains can not set maximum open files because it has reached the OS max file descriptor limits. Here is the sample output.

$ ./bin/redis-server
28436:C 25 Nov 20:10:03.978 # Warning: no config file specified, using the default config. In order to specify a config file use ./bin/redis-server /path/to/redis.conf
28436:M 25 Nov 20:10:03.979 # You requested maxclients of 10000 requiring at least 10032 max file descriptors.
28436:M 25 Nov 20:10:03.979 # Server can't set maximum open files to 10032 because of OS error: Operation not permitted.
28436:M 25 Nov 20:10:03.979 # Current maximum open files is 4096. maxclients has been reduced to 4064 to compensate for low ulimit. If you need higher maxclients increase 'ulimit -n'.
[...CUT...]

When you try to increase the maximum file descriptor using ulimit as root by issuing sudo it returns an error.

$ sudo ulimit -n 65000
sudo: ulimit: command not found

Wow, WTF is that? ulimit is a shell built so giving sudo an instruction to run a command called ulimit will not work. It will the same as statement below.

Read more »

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