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distinctcountull.md

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This section contains reference documentation for the DISTINCTCOUNTULL function.

DISTINCTCOUNTULL

The UltraLogLog Sketch from Dynatrace is a variant of HyperLogLog and is used for approximate distinct counts. The UltraLogLog sketch shares many of the same properties of a typical HyperLogLog sketch but requires less space and also provides a simpler and faster estimator.

Pinot uses an production-ready Java implementation available in Hash4j available under the Apache license.

For exact distinct counting, see DISTINCTCOUNT.

Signature

distinctCountULL(<ullSketchColumn>, <ullSketchPrecision>) -> Long

  • ullSketchColumn (required): Name of the column to aggregate on.
  • ullSketchPrecision (optional): p which is the precision parameter, which controls both the size and accuracy of the sketch. If not supplied, the Helix default is used.

Usage Examples

These examples are based on the Batch Quick Start.

select distinctCountULL(teamID) AS value
from baseballStats
value
150 
select distinctCountULL(teamID, 14) AS value
from baseballStats
value
149