Shannon Ladymon has documented Hive macros in the wiki <https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-Create/DropMacro>, using examples from HIVE-2655 <https://issues.apache.org/jira/browse/HIVE-2655> and HIVE-13372 <https://issues.apache.org/jira/browse/HIVE-13372>. Review comments, corrections, and additions are welcome.
Thanks, Shannon! -- Lefty On Sun, Sep 13, 2015 at 10:53 PM, Lefty Leverenz <[email protected]> wrote: > HIVE-2655 <https://issues.apache.org/jira/browse/HIVE-2655> added macros > in release 0.12.0, so I've added a TODOC12 label and doc note to it. > > Thank you Elliot for drawing this to our attention. > > -- Lefty > > > On Fri, Sep 11, 2015 at 3:41 PM, Edward Capriolo <[email protected]> > wrote: > >> Macro's are in and tested. No one will remove them. The unit tests ensure >> they keep working. >> >> On Fri, Sep 11, 2015 at 3:38 PM, Elliot West <[email protected]> wrote: >> >>> Hi, >>> >>> I noticed some time ago the Hive Macro feature. To me at least this >>> seemed like an excellent addition to HQL, allowing the user to encapsulate >>> complex column logic as an independent HQL, reusable macro while avoiding >>> the complexities of Java UDFs. However, few people seem to be aware of them >>> or use them. If you are unfamiliar with macros they look like this: >>> >>> hive> create temporary macro MYSIGMOID(x DOUBLE) >>> > 2.0 / (1.0 + exp(-x)); >>> OK >>> >>> hive> select MYSIGMOID(1.0) from dual; >>> OK >>> >>> 1.4621171572600098 >>> >>> >>> As far as I can tell, they are no longer documented on the Hive wiki. >>> There is a tiny reference to them in the O'Reilly 'Programming Hive' book >>> (page 185). Can anyone advise me on the following: >>> >>> - Are there are plans to keep or remove this functionality? >>> - Are there are plans to document this functionality? >>> - Aside from limitations of HQL are there compelling reasons not to >>> use macros? >>> >>> Thanks - Elliot. >>> >>> >> >
