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Posted to dev@drill.apache.org by GitBox <gi...@apache.org> on 2022/01/26 10:28:07 UTC

[GitHub] [drill] jnturton edited a comment on pull request #2432: DRILL-7994: Dependency version updates for severe vulnerabilities

jnturton edited a comment on pull request #2432:
URL: https://github.com/apache/drill/pull/2432#issuecomment-1022065612


   @tdunning, that would be great thanks.  Here the selectivity of a range predicate on an integer column is estimated using a set of quantile estimates, here termed an equidepth histogram (see [NumericEquiDepthHistogram](https://github.com/apache/drill/blob/4aefcef2b665c5737471664912a26ef6ed9a6cfc/exec/java-exec/src/main/java/org/apache/drill/exec/planner/common/NumericEquiDepthHistogram.java)).  The quantile estimates are recovered from a MergingDigest over the integer column that was created by an earlier `ANALYSE TABLE` command.  If said quantile estimates have shifted then that would explain what we're seeing...


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