Alex Behm has posted comments on this change. ( http://gerrit.cloudera.org:8080/9540 )
Change subject: IMPALA-3916: [DOCS] Reserved keywords updated for Impala 3.0 ...................................................................... Patch Set 2: (2 comments) http://gerrit.cloudera.org:8080/#/c/9540/2/docs/topics/impala_reserved_words.xml File docs/topics/impala_reserved_words.xml: http://gerrit.cloudera.org:8080/#/c/9540/2/docs/topics/impala_reserved_words.xml@22 PS2, Line 22: <title>Impala Reserved Words</title> I think this page could use some general revamping. In particular, we should show how the list of Impala keywords across different Impala versions stacks up against the SQL2016 list of reserved words. Tianyi has a nice spreadsheet. That table will show that some SQL2016 reserved words are not reserved in Impala and that some Impala reserved words are not part of SQL2016. Given that discrepancy, we should explain Impala's process for deciding whether a particular SQL2016 word should be reserved or not in Impala. Tianyi can provide more details, but I can summarize the process roughly here: * By default, Impala wants to be standard conforming, so we wish to have the same list of reserved words as SQL2016 * At the same time, Impala wants to be compatible with earlier versions of Impala to avoid breaking existing tables/workloads. So we remove from the SQL2016 list of reserved words those that are Impala built-in functions that do not need to be reserved (COUNT, AVG are examples) * For those remaining SQL2016 words we use our gut feeling to decide whether user are likely to have databases/tables/columns with those names. If we feel that a word is likely to be used already then we look whether Impala is going to need to reserve it to implement new SQL features that use it. If a word is likely to be used and there is a low chance of Impala need it to be reserved in the future, then we do not reserve that word. Otherwise, we reserve that SQL2016 word in Impala. http://gerrit.cloudera.org:8080/#/c/9540/2/docs/topics/impala_reserved_words.xml@71 PS2, Line 71: <codeblock rev="ver"> Without looking at -- To view, visit http://gerrit.cloudera.org:8080/9540 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I09dbaf5e2d22f07a8bca8a601c04e94f3a4b36a0 Gerrit-Change-Number: 9540 Gerrit-PatchSet: 2 Gerrit-Owner: Alex Rodoni <[email protected]> Gerrit-Reviewer: Alex Behm <[email protected]> Gerrit-Reviewer: Alex Rodoni <[email protected]> Gerrit-Reviewer: Greg Rahn <[email protected]> Gerrit-Reviewer: John Russell <[email protected]> Gerrit-Reviewer: Tianyi Wang <[email protected]> Gerrit-Comment-Date: Fri, 09 Mar 2018 17:47:25 +0000 Gerrit-HasComments: Yes
