Cardinality

The cardinality is the number of distinct elements in a set.

Calculating the exact cardinality of a multiset requires an amount of memory proportional to the cardinality, which is impractical for very large data sets.

• Linear Counter
  • Build a counter
  • Index element into the counter
  • Size of the counter in bytes
  • Length of the counter
  • Count of unique elements in the counter
• Probabilistic Counter
  • Build a counter
  • Index element into the counter
  • Size of the counter in bytes
  • Length of the counter
  • Count of unique elements in the counter
• HyperLogLog
  • Build a counter
  • Index element into the counter
  • Size of the counter in bytes
  • Length of the counter
  • Count of unique elements in the counter