Get sizes of all sorted sets with a given prefix

Question

I got several sorted sets with a common prefix (itemmovements:) in Redis.

I know we can use ZCOUNT to get the number of items for a single (sorted set) key like this:

127.0.0.1:6379> zcount itemmovements:8 0 1000000000
(integer) 23

(I am able to do this, since I know the range of the item scores.)

How to run this in a loop for all keys prefixed itemmovements:?

Taking hint from How to atomically delete keys matching a pattern using Redis I tried this:

127.0.0.1:6379> EVAL "return redis.call('zcount', unpack(redis.call('keys', ARGV[1])), 0, 1000000000)" 0 itemmovements:*
(integer) 150

but as you can see it just returns a single number (which happens to be the size of itemmovements:0, the first value returned by keys).

score 0 · Accepted Answer · answered Sep 01 '15 at 01:22

0

I realized I did not understand what that lua code in EVAL was doing. The code below works fine:

eval "local a = {}; for _,k in ipairs(redis.call('keys', 'itemmovements:*')) do table.insert(a, k); table.insert(a, redis.call('zcount', k, 0, 1000000000)); end; return a" 0

answered Sep 01 '15 at 01:22

arun

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Note that using `KEYS` is potentially dangerous and shouldn't be done on production. – Itamar Haber Sep 01 '15 at 09:12
@ItamarHaber: thanks and agreed. I had only 20 keys with that prefix so this is fine for my case. – arun Sep 01 '15 at 14:59
The command-that-must-not-be-named is dangerous even if you don't have any keys with that prefix – Itamar Haber Sep 01 '15 at 16:52

Get sizes of all sorted sets with a given prefix

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