Skip to content
HotKVDocs

Ask the HotKV docs

Answers come only from these docs and can be wrong; check the linked pages before you rely on them.

CMS.INITBYPROB

Last updated 
CMS.INITBYPROB key error probability
Group
Count-min sketch
Complexity
O(1)
Arity
-1 (at least 1 words, counting the command name)
Flags
fast
Keys
first 1, last 1, step 1
HotKV Cloud
All plans
On-Premise
no license needed

CMS.INITBYPROB creates an empty Count-min sketch at key, sized so that an estimate overcounts by more than error times the total of all increments only with a chance of probability.

For example, error 0.001 and probability 0.01 mean: with 99% certainty, an item’s estimate is at most its true count plus 0.1% of everything counted.

The server derives the sketch’s width and depth from these values, the same way RedisBloom does. CMS.INFO shows the result.

Arguments

Section titled “Arguments”
Argument Meaning
error Allowed overcount, as a fraction of the total count. Between 0 and 1, exclusive.
probability Chance of exceeding that overcount. Between 0 and 1, exclusive.

Return value

Section titled “Return value”
Case RESP2 RESP3
Created Simple string OK Simple string OK

Error replies:

  • CMS: key already exists if the key exists (with any type).
  • CMS: invalid overestimation value and CMS: invalid prob value for values outside (0, 1).
  • CMS: Insufficient memory to create the key when the sketch would not fit in memory.

Examples

Section titled “Examples”
127.0.0.1:6379> CMS.INITBYPROB searches 0.001 0.01
OK
127.0.0.1:6379> CMS.INFO searches
1) width
2) (integer) 2000
3) depth
4) (integer) 7
5) count
6) (integer) 0
127.0.0.1:6379> CMS.INITBYPROB other 0 0.01
(error) CMS: invalid overestimation value

Compatibility

Section titled “Compatibility”

Same as CMS.INITBYPROB in RedisBloom, with the same dimensions for the same arguments.

See also

Section titled “See also”

CMS.INITBYDIM, CMS.INCRBY, CMS.INFO