Hi Bejoy, Thanks for the reply, how can I know data skew among reducers.
Regards Abhi Sent from my iPhone On Sep 26, 2012, at 1:20 PM, Bejoy KS <[email protected]> wrote: > Hi Abshiek > > Group by performance can be improved by the following > 1)enabling map side aggregation. In latest versions it is enabled by default > SET hive.map.aggr = true; > > 2)Is there a data skew observed in some of the reducers? > If so a better performance can be yielded by setting the following property > SET hive.groupby.skewindata=true; > > > Regards, > Bejoy KS > > From: Abhishek <[email protected]> > To: Hive <[email protected]> > Sent: Wednesday, September 26, 2012 10:31 PM > Subject: How to optimize a group by query > > Hi all, > > I have written a query with group by clause, it is consuming lot of time is > there any way to optimize this any configuration property or some thing. > > Regards > Abhi > > > Sent from my iPhone >
