fix(stream): handle 0.0
case of approx percentile, and fix computation of quantile_count
#18546
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What's changed and what's your intention?
Closes #18545
As per title. There were two bugs discovered.
First,
0.0
is not properly handled. It will result in a logarithmic base of1
, and the behaviour is undefined. So we will just ban it first, until streamingpercentile_cont
is supported, then we can remap it to that instead.Next, for
quantile_count
should beq(n-1)
as mentioned in the ddsketch paper. This PR fixes it.Checklist
./risedev check
(or alias,./risedev c
)Documentation
Release note
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