Csaba Ringhofer has posted comments on this change. ( http://gerrit.cloudera.org:8080/9980 )
Change subject: IMPALA-6723: [DOCS] Hints for CTAS ...................................................................... Patch Set 2: (4 comments) http://gerrit.cloudera.org:8080/#/c/9980/2/docs/topics/impala_hints.xml File docs/topics/impala_hints.xml: http://gerrit.cloudera.org:8080/#/c/9980/2/docs/topics/impala_hints.xml@59 PS2, Line 59: Inserting into partitioned Parquet tables, where many memory buffers could be allocated on each host to : hold intermediate results for each partition. : </li> : <li> : Creating a table based on column definitions from another table and : copying data from the source table, These two use cases are practically the same, as CTAS is practically a CREATE + an INSERT...SELECT, so I would try to merge these into one paragraph, or remove the CTAS version from this example section. http://gerrit.cloudera.org:8080/#/c/9980/2/docs/topics/impala_hints.xml@287 PS2, Line 287: does not add exchange node before : inserting to partitioned tables and disables re-partitioning. I think that it would be clearer if this was explained in the SHUFFLE paragraph, like "SHUFFLE adds an exchange node which re-partitions the result of the SELECT based on the partitioning columns of the target table. This makes a partition to be written only by a single node, ..." http://gerrit.cloudera.org:8080/#/c/9980/2/docs/topics/impala_hints.xml@319 PS2, Line 319: partition I think that "by each partitioning column" would be clearer. http://gerrit.cloudera.org:8080/#/c/9980/2/docs/topics/impala_hints.xml@328 PS2, Line 328: <codeph>/* +NOCLUSTERED */</codeph> does not sort by primary key : before insert. Use this hint when inserting to Kudu tables. This : hint has no effect on HDFS tables currently as this is the default : behavior. This hint is available in <keyword keyref="impala28_full" : /> or higher. </li> Since IMPALA-5293 (Impala 3.x only) the default is CLUSTERED behavior for HDFS tables, so NOCLUSTERED will have effect on them. -- To view, visit http://gerrit.cloudera.org:8080/9980 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I01057d59127d6193bdb69a2a181a386a039e08f5 Gerrit-Change-Number: 9980 Gerrit-PatchSet: 2 Gerrit-Owner: Alex Rodoni <arod...@cloudera.com> Gerrit-Reviewer: Alex Behm <alex.b...@cloudera.com> Gerrit-Reviewer: Csaba Ringhofer <csringho...@cloudera.com> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Lars Volker <l...@cloudera.com> Gerrit-Reviewer: Thomas Tauber-Marshall <tmarsh...@cloudera.com> Gerrit-Comment-Date: Wed, 11 Apr 2018 14:42:51 +0000 Gerrit-HasComments: Yes
