Bill: See http://blog.sematext.com/2012/04/09/hbasewd -avoid-regionserver-hotspotting-despite-writing-records-with-sequential-keys/
FYI On Sun, Jan 19, 2014 at 4:02 PM, Bill Q <[email protected]> wrote: > Hi Amit, > Thanks for the reply. > > If I understand your suggestion correctly, and assuming we have 100 region > servers, I would have to do 100 scans to merge reads if I want to pull any > data for a specific date. Is that correct? Is the 100 scans the most > efficient way to deal with this issue? > > Any thoughts? > > Many thanks. > > > Bill > > > On Sun, Jan 19, 2014 at 4:02 PM, Amit Sela <[email protected]> wrote: > > > If you'll use bulk load to insert your data you could use the date as key > > prefix and choose the rest of the key in a way that will split each day > > evenly. You'll have X regions for Evey day >> 14X regions for the two > weeks > > window. > > On Jan 19, 2014 8:39 PM, "Bill Q" <[email protected]> wrote: > > > > > Hi, > > > I am designing a schema to host some large volume of data over HBase. > We > > > collect daily trading data for some markets. And we run a moving window > > > analysis to make predictions based on a two weeks window. > > > > > > Since everybody is going to pull the latest two weeks data every day, > if > > we > > > put the date in the lead positions of the Key, we will have some hot > > > regions. So, we can use bucketing (date to mode bucket number) approach > > to > > > deal with this situation. However, if we have 200 buckets, we need to > run > > > 200 scans to extract all the data in the last two weeks. > > > > > > My questions are: > > > 1. What happens when each scan return the result? Will the scan result > be > > > sent to a sink like place that collects and concatenate all the scan > > > results? > > > 2. Why having 200 scans might be a bad thing compared to have only 10 > > > scans? > > > 3. Any suggestions to the design? > > > > > > Many thanks. > > > > > > > > > Bill > > > > > >
