It's currently not supported. It would require an enhancement to the storage plugin.
Feel free to file an enhancement jira, or f you want to experiment with it yourself, you can take a look at the HBaseGroupScan code, which is where the assignment logic is located. Currently, we don't split the work within a region, but it shouldn't be too difficult to modify the code to do this. The difficult part is that we don't necessarily have a good idea what the distribution of keys is within a region, so we can't be sure that we split split the region evenly. The easy way to handle it would be to simply assume the keys are evenly distributed between the start and end key, and split half way between (or 1/3 or whatever, depending on how many fragments per region you want). On Tue, Jun 9, 2015 at 11:20 AM, Andy Pernsteiner <[email protected] > wrote: > I've been doing some experimentation with Drill (1.0) against MaprDB. I > believe I'd see similar behavior vs HBASE, although I haven't tried yet. > > I have a 11GB table, which is split into 8 regions (not perfectly > balanced, some have 2x the # of records as others). > > When I run a drill query which results in a full table scan (eg: select > *..), I notice in the profile that there are only 8 minor fragments > assigned. This seems to coincide with other tests which I've ran that also > seem to assign one minor fragment per region. > > Is this expected? Are there any ways of increasing the parallelism on > table scans? (eg: every XX records, or assign XX fragments per region) > > > > -- > Andy Pernsteiner > Manager, Field Enablement > ph: 206.228.0737 > > www.mapr.com > > Now Available - Free Hadoop On-Demand Training > < > http://www.mapr.com/training?utm_source=Email&utm_medium=Signature&utm_campaign=Free%20available > > > -- Steven Phillips Software Engineer mapr.com
