How to sum value of all Key in Redis

Question

In Redis DB, i have many key in String type to save dowloads time with a application, example:

   Key            value
20131028:1         100
20131028:2         15
20131028:3         10
..........

I want to sum all value of all key by redis command, please helpe me solve it. Thank you so much.

Answer 1

Redis is not designed to do this kind of things. You will better served by a RDBMS, MongoDB, or something like ElasticSearch.

Still, if you need to do it (to be launched from a shell):

$ redis-cli keys '20131028:*' | awk '{print "get "$1}' | redis-cli | awk '{x+=$1} END { print x }'

An other way to do it is to use a Lua server-side script:

$ redis-cli eval "local keys = redis.call('keys',KEYS[1]) ; local sum=0 ; for _,k in ipairs(keys) do sum = sum + redis.call('get',k) end ; return sum" 1 '20131028:*'

In both cases, performance will suck if you have many keys in the Redis instance, and the instance will be blocked for all connections while the keys are scanned.