Greg Rahn has posted comments on this change. Change subject: Release note updates for Impala 2.8 ......................................................................
Patch Set 1: (3 comments) http://gerrit.cloudera.org:8080/#/c/5668/1/docs/topics/impala_incompatible_changes.xml File docs/topics/impala_incompatible_changes.xml: PS1, Line 111: This is a change from early experimental versions of Impala + Kudu, where columns : had the <codeph>NOT NULL</codeph> attribute by default. > I don't think this is correct. AFAIK the default behavior is the same and w The GA behavior is columns are nullable by default, unless they are part of the PK. There was a change that inverted this behavior for a time but now impala explicitly implements the expected RDBMS behavior. Perhaps that is where the confusion comes from. http://gerrit.cloudera.org:8080/#/c/5668/1/docs/topics/impala_new_features.xml File docs/topics/impala_new_features.xml: PS1, Line 66: The <codeph>COMPUTE STATS</codeph> statement can : take advantage of multithreading. Not sure if you want to be more specific here as the default for Parquet tables will now be MT_DOP=4. PS1, Line 91: allows Impala <codeph>INSERT</codeph> operations : that use dynamic partitioning to process a high number of : partitions in a single statement. SORTBY adds ordering for non-partition key columns to better support the effectiveness of min/max data elimination techniques (still a WIP). CLUSTERED adds ordering for the partition key columns such that there is only a single writer for any given partition thus reducing the overall memory needed when inserting into many partitions. Both of these are mentioned in the description of IMPALA-2522. -- 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: 1 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: John Russell <jruss...@cloudera.com> Gerrit-Reviewer: Ambreen Kazi <ambreen.k...@cloudera.com> Gerrit-Reviewer: Anonymous Coward #250 Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com> Gerrit-Reviewer: Dimitris Tsirogiannis <dtsirogian...@cloudera.com> Gerrit-Reviewer: Greg Rahn <gr...@cloudera.com> Gerrit-Reviewer: Jim Apple <jbapple-imp...@apache.org> Gerrit-Reviewer: Matthew Jacobs <m...@cloudera.com> Gerrit-HasComments: Yes
