5 / 6 Counters, Top-K & Sketches

Merge Without Regret

Your fleet builds sketches per shard and combines them at read time. More than one of these merges is exact, meaning the combined sketch is bit-for-bit what you would have got from feeding the whole stream to a single sketch. Select every merge that is exact.

A

Two Bloom filters of identical size and hash functions, merged with a bitwise OR.

B

Two per-shard top-10 lists, concatenated and re-sorted by count to get the global top 10.

C

Two HyperLogLogs with the same mm, merged by taking the per-register maximum.

D

Two count-min sketches with identical width, depth and hash functions, merged by adding cells position by position.

E

Two HyperLogLogs intersected by taking the per-register minimum, to get the size of the overlap.