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CMS.MERGE

Syntax​

CMS.MERGE destination numkeys source [source ...] [WEIGHTS weight [weight ...]]

Time complexity: O(n·w·d) where n is the number of source sketches, w is the width, and d is the depth

ACL categories: @cms

Merges multiple source Count-Min Sketches into destination. The destination key must be pre-initialized via CMS.INITBYDIM or CMS.INITBYPROB before calling this command — if it does not exist, an error is returned. All sketches (sources and destination) must have identical width and depth dimensions. The destination's existing counts are overwritten.

  • numkeys: The number of source sketch keys to merge.
  • source: One or more source sketch keys.
  • WEIGHTS: Optional integer multipliers applied to each source sketch before merging. Each source's counters are multiplied by its corresponding weight prior to being summed into the destination. Defaults to 1 for all sources if omitted.

Return​

Simple string reply: OK if the merge was successful.

Examples​

dragonfly> CMS.INITBYDIM cms1 2000 5
OK

dragonfly> CMS.INITBYDIM cms2 2000 5
OK

dragonfly> CMS.INCRBY cms1 item1 10 item2 3
1) (integer) 10
2) (integer) 3

dragonfly> CMS.INCRBY cms2 item1 5 item3 7
1) (integer) 5
2) (integer) 7

dragonfly> CMS.INITBYDIM cms_merged 2000 5
OK

dragonfly> CMS.MERGE cms_merged 2 cms1 cms2
OK

dragonfly> CMS.QUERY cms_merged item1 item2 item3
1) (integer) 15
2) (integer) 3
3) (integer) 7

Using WEIGHTS to scale contributions before merging:

dragonfly> CMS.INITBYDIM cms_weighted 2000 5
OK

dragonfly> CMS.MERGE cms_weighted 2 cms1 cms2 WEIGHTS 2 1
OK

dragonfly> CMS.QUERY cms_weighted item1 item2 item3
1) (integer) 25
2) (integer) 6
3) (integer) 7

See also​

CMS.INITBYDIM | CMS.INITBYPROB | CMS.INCRBY | CMS.INFO