Alex Behm has posted comments on this change. Change subject: Release note updates for Impala 2.8 ......................................................................
Patch Set 7: (2 comments) http://gerrit.cloudera.org:8080/#/c/5668/7/docs/topics/impala_new_features.xml File docs/topics/impala_new_features.xml: Line 65: <p rev="IMPALA-4572"> We should definitely also highlight IMPALA-1430 which fixes the slow COMPUTE STATS issue with TIMESTAMP. COMPUTE STATS is now codegen'd even if there are TIMESTAMP columns. The JIRA is not yet marked as fixed because there is some follow-on work, but the COMPUTE STATS issue specifically has been fixed. Line 130: format <codeph>TIMESTAMP</codeph> values, such as the result A naked now() function is a particularly bad example, because now() is already constant within a query, so does not benefit from this improvement. A better example is something like: WHERE date_col = to_date(now() - interval 1 day) the right-hand size expression is somewhat complicated and expensive to evaluate for every row. Constant folding makes this significantly faster. -- To view, visit http://gerrit.cloudera.org:8080/5668 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I7c47f422e509cec6d3eb8aaa82294b584f393aed Gerrit-PatchSet: 7 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: John Russell <jruss...@cloudera.com> Gerrit-Reviewer: Alex Behm <alex.b...@cloudera.com> Gerrit-Reviewer: Ambreen Kazi <ambreen.k...@cloudera.com> Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com> Gerrit-Reviewer: Dimitris Tsirogiannis <dtsirogian...@cloudera.com> Gerrit-Reviewer: Greg Rahn <gr...@cloudera.com> Gerrit-Reviewer: Henry Robinson <he...@cloudera.com> Gerrit-Reviewer: Jim Apple <jbapple-imp...@apache.org> Gerrit-Reviewer: John Russell <jruss...@cloudera.com> Gerrit-Reviewer: Laurel Hale <lau...@cloudera.com> Gerrit-Reviewer: Matthew Jacobs <m...@cloudera.com> Gerrit-Reviewer: Silvius Rus <s...@cloudera.com> Gerrit-HasComments: Yes
