This section contains reference documentation for the PERCENTILEKLL function.
KLL Sketch
is an approxiamate quantiles algorithm which targets optimal space for a given accuracy. PERCENTILEKLL
is a percentile calculation aggregation function based on Apache Datasketches KLL Doubles Sketch implementation.
Pinot also offers a 'raw' variant, PERCENTILEKLLRAW
, which returns the serialized sketch that can be used for calculating 'rank' or 'histogram'.
All of the variants of PercentileKLL
also support raw sketches in Pinot columns. This means you can create KLL Doubles sketches outside of Pinot and ingest them into columns as binary strings. PercentileKLL
will identify these columns merge them to produce aggregate results.
PercentileKLL(column, percentile, kValue) -> Double
column
(required): Name of the column to aggregate on. If the column is a multi value column, use PERCENTILEKLLMV
variant.
percentile
(required): Percentile value to be calculated [0..100]
kValue
: Integer value which determines the size of the sketch. Default value is 200
which corresponds to a normalized rank error of about 1.65%. For details please see the accuracy vs size chart.
DelayP90 |
---|
Carrier | MedianDelay |
---|---|
40
MQ
28
B6
28
EV
24