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Sort Stage Query
Posted: Wed Oct 12, 2011 1:55 am
by udayk_2007
Hello guys
Can anybody please clarify ,what is the difference between 'Create cluster Key Change Column' and 'Create Key Change Column' option in Sort Stage ?
From reading the doc,both the options looks similar.
Thanks in advance for your help
Regards
Ulhas
Re: Sort Stage Query
Posted: Wed Oct 12, 2011 2:28 am
by sacheens23
Re: difference between CCKCC and CKCC
Posted: Wed Oct 12, 2011 9:11 pm
by jiegao
How do we know if the data are "previously grouped"? "Previously Sorted" is easy to understand. I have a job contains JOIN stage followed by Sort stage. Data are sorted using link sort before the JOIN stage. Can I use "Previously Goruped" option? Why cannot use "Previously Sorted" option? Thanks in advance.
Posted: Wed Oct 12, 2011 10:48 pm
by prakashdasika
If you only partition on a key and do not sort, it is 'grouped'. If you do partition and sort on the key then it is 'sorted'.
If the sort keys in the sort stage are same as the sort keys in join stage then you need to use - Create Cluster Key Change Column (Don't sort previously sorted) , If the keys are different, define the new keys and use - Create Key Change Column.
Posted: Thu Oct 13, 2011 7:45 am
by jiegao
Thanks prakashdasika for your answer. That is exactly what I was curious about.
Posted: Thu Oct 13, 2011 1:04 pm
by ray.wurlod
Please mark this thread as Resolved