Tim Armstrong has posted comments on this change. ( http://gerrit.cloudera.org:8080/12136 )
Change subject: IMPALA-8021: Add estimated cardinality to EXPLAIN output ...................................................................... Patch Set 12: (1 comment) http://gerrit.cloudera.org:8080/#/c/12136/12/fe/src/test/java/org/apache/impala/testutil/TestUtils.java File fe/src/test/java/org/apache/impala/testutil/TestUtils.java: http://gerrit.cloudera.org:8080/#/c/12136/12/fe/src/test/java/org/apache/impala/testutil/TestUtils.java@207 PS12, Line 207: If found, then parse the values and compare them. Report a match : * if the values are within 5%, else report a mismatch. > Actually, looking at this again, it appears that we are just comparing the Yeah I'm not sure if we expect the cardinality estimates to be exactly reproducible from run-to-run. I can't think of a reason why they wouldn't be exactly equal - the collected stats should always be the same (there's no randomness or non-determinism in the cardinality there AFAIK). There are some other cases where there's variation in the exact numbers produced by the planner - memory reservations for scans depend on the file size, which can vary over time slightly for various reasons. I figured that having this tolerance factor didn't significantly weaken the tests (especially since we didn't even have cardinality before) and would alleviate some amount of labour if estimates change marginally. -- To view, visit http://gerrit.cloudera.org:8080/12136 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ie9aa2d715b04cbb279aaffec8c5692686562d986 Gerrit-Change-Number: 12136 Gerrit-PatchSet: 12 Gerrit-Owner: Paul Rogers <prog...@cloudera.com> Gerrit-Reviewer: Bharath Vissapragada <bhara...@cloudera.com> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Paul Rogers <prog...@cloudera.com> Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com> Gerrit-Comment-Date: Mon, 07 Jan 2019 17:42:22 +0000 Gerrit-HasComments: Yes
