Home | About | Sematext search-lucene.com search-hadoop.com
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB
 Search Hadoop and all its subprojects:

Switch to Threaded View
Hive >> mail # user >> Any Scenarios in which Views impose performance penalties


Copy link to this message
-
Re: Any Scenarios in which Views impose performance penalties
Thanks for the inputs Edward and Ricky.  I did look at the relevant source
code on the version we are using 0.9 and it does not appear there would be
any impact of views on the underlying sql - it does column aliasing and
checks  that the query partition columns match partition columns of the
underlying tables.    Neither would lead to incorrect partition pruning.

2013/8/20 Ricky Saltzer <[EMAIL PROTECTED]>

> My apologies, being on both a Hive and Impala mailing list can be
> confusing ;).
>
>
> On Tue, Aug 20, 2013 at 10:40 PM, Edward Capriolo <[EMAIL PROTECTED]>wrote:
>
>> Views are logical . The view is compiled and has no penalty over the
>> standard query.
>>
>>
>> On Tuesday, August 20, 2013, Ricky Saltzer <[EMAIL PROTECTED]> wrote:
>> > Since this bug was in Impala's query planner, I'm sure Hive is
>> unaffected.
>> >
>> > On Aug 20, 2013 10:15 PM, "Stephen Boesch" <[EMAIL PROTECTED]> wrote:
>> >>
>> >> Thanks v much Ricky.  Is this fixed in hive 0.11 - or going to be
>> later i.e. 0.12?
>> >>
>> >> 2013/8/20 Ricky Saltzer <[EMAIL PROTECTED]>
>> >>>
>> >>> Although this is already fixed in the next and upcoming impala
>> release, you might want to be aware of the following view limitation.
>> >>>
>> >>> https://issues.cloudera.org/browse/IMPALA-495
>> >>>
>> >>> On Aug 20, 2013 7:16 PM, "Stephen Boesch" <[EMAIL PROTECTED]> wrote:
>> >>>>
>> >>>> Views should theoretically not incur performance penalties: they
>> simply represent queries. Are there situtions that things are "not that
>> simple" - i.e. views may actually result in different exeucution plans than
>> the underlying sql?
>> >>>> Additionally, are there views-related bugs that we should be aware
>> of that would limit the occasions that we could use them?
>> >>>> Thanks for the pointers.
>> >>>>
>> >>
>> >
>>
>
>
>
> --
> Ricky Saltzer
> Tools Developer
> http://www.cloudera.com
>
>
>
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB