Thank you for pointing this out. The 'hive.cache.expr.evaluation'
parameter was added by
HIVE-4209<https://issues.apache.org/jira/browse/HIVE-4209> and
it needs to be included in the wiki. Its description is in
hive-default.xml.template:
If true, evaluation result of deterministic expression referenced twice or
> more will be cached. For example, in filter condition like ".. where key +
> 10 > 10 or key + 10 = 0" "key + 10" will be evaluated/cached once and
> reused for following expression ("key + 10 = 0"). Currently, this is
> applied only to expressions in select or filter operator.
Do you want to provide more information than that? To contribute to the
wiki, create a Confluence
account<https://cwiki.apache.org/confluence/signup.action>and send a
message to this list asking for wiki editing privilege and
giving your account name. But if you just want the description to be added
to the wiki, I can take care of that.
If you have additional information, it might not belong in Configuration
Properties<https://cwiki.apache.org/confluence/display/Hive/Configuration+Properties>
(although
once the parameter is there it can link to another page for details). The
Select<https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Select>page
is one possibility, or maybe you'll find a better place for it.
If you want to revise the description in hive-default.xml.template, you
need to open a JIRA and patch the file.
-- Lefty
On Sat, May 24, 2014 at 1:01 AM, 郭士伟 <guoshi...@gmail.com> wrote:
> I have used a configuration property 'hive.cache.expr.evaluation' in hive
> 0.12 recently and found it useful. But I cannot find any documents about it
> on the wiki page:
> https://cwiki.apache.org/confluence/display/Hive/Configuration+Properties.
> Indeed, I pick it up from the source code.
>
> I think it maybe useful for other hive users if I can write some documents
> about the property.
>
> So, can anyone give me some pointers that how can I make the change happen
> ?
>
> Thanks, anyway.
>
