GitHub user mgaido91 opened a pull request: https://github.com/apache/spark/pull/21133
[SPARK-24013][SQL] Remove unneeded compress in ApproximatePercentile ## What changes were proposed in this pull request? `ApproximatePercentile` contains a workaround logic to compress the samples since at the beginning `QuantileSummaries` was ignoring the compression threshold. This problem was fixed in SPARK-17439, but the workaround logic was not removed. So we are compressing the samples many more times than needed: this could lead to critical performance degradation. ## How was this patch tested? added UT You can merge this pull request into a Git repository by running: $ git pull https://github.com/mgaido91/spark SPARK-24013 Alternatively you can review and apply these changes as the patch at: https://github.com/apache/spark/pull/21133.patch To close this pull request, make a commit to your master/trunk branch with (at least) the following in the commit message: This closes #21133 ---- commit 0ac3b4f1ffe05f51abfb58810c385a4daae016c9 Author: Marco Gaido <marcogaido91@...> Date: 2018-04-23T20:40:06Z [SPARK-24013][SQL] Remove unneeded compress in ApproximatePercentile ---- --- --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org