MaxGekk opened a new pull request #29784: URL: https://github.com/apache/spark/pull/29784
### What changes were proposed in this pull request? 1. Change the target error calculation according to the paper [Space-Efficient Online Computation of Quantile Summaries](http://infolab.stanford.edu/~datar/courses/cs361a/papers/quantiles.pdf). It says that the error `e = max(gi, deltai)/2` (see the page 59). Also this has clear explanation [ε-approximate quantiles](http://www.mathcs.emory.edu/~cheung/Courses/584/Syllabus/08-Quantile/Greenwald.html#proofprop1). 2. Added a test to check different accuracies. 3. Added an input CSV file `percentile_approx-input.csv.bz2` to the resource folder `sql/catalyst/src/main/resources` for the test. ### Why are the changes needed? To fix incorrect percentile calculation, see an example in SPARK-32908. ### Does this PR introduce _any_ user-facing change? Yes ### How was this patch tested? - By running existing tests in `QuantileSummariesSuite` and in `ApproximatePercentileQuerySuite`. - Added new test `SPARK-32908: maximum target error in percentile_approx` to `ApproximatePercentileQuerySuite`. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
