Ah, sure. That's a good idea. I know how to do it now. :) Thanks for the help.
Jianshi On Thu, Aug 28, 2014 at 12:29 PM, Ted Yu <[email protected]> wrote: > You can enhance ColumnRangeFilter to return the first column in the range. > > In its filterKeyValue(Cell kv) method: > > int cmpMax = Bytes.compareTo(buffer, qualifierOffset, qualifierLength, > > this.maxColumn, 0, this.maxColumn.length); > > if (this.maxColumnInclusive && cmpMax <= 0 || > > !this.maxColumnInclusive && cmpMax < 0) { > > return ReturnCode.INCLUDE; > > } > > ReturnCode.NEXT_ROW should be returned (for subsequent columns) once > ReturnCode.INCLUDE is returned for the first column in range. > > Cheers > > > On Wed, Aug 27, 2014 at 9:05 PM, Jianshi Huang <[email protected]> > wrote: > > > Very similar. We setup a column range (we're using ColumnRangeFilter > right > > now), and we want the first column in the range. > > > > The problem we have a lot of rows. > > > > If there's no such capability, then we need to control the parallelism > > ourselves. > > > > Shall I sort the rows first before scanning? Will a random order be more > > efficient if we have many servers? > > > > Jianshi > > > > > > On Thu, Aug 28, 2014 at 1:44 AM, Ted Yu <[email protected]> wrote: > > > > > So you want to specify several columns. e.g. c2, c3, and c4, the GET is > > > supposed to return the first one of them (doesn't have to be c2, can be > > c3 > > > if c2 is absent) ? > > > > > > To my knowledge there is no such capability now. > > > > > > Cheers > > > > > > > > > On Wed, Aug 27, 2014 at 10:28 AM, Jianshi Huang < > [email protected] > > > > > > wrote: > > > > > > > On Thu, Aug 28, 2014 at 1:20 AM, Jianshi Huang < > > [email protected]> > > > > wrote: > > > > > > > > > > > > > > There's a special but common case that for each row we only need > the > > > > first > > > > > column. Is there a better way to do this than multiple scans + > > take(1)? > > > > > > > > > > > > > We still need to set a column range, is there a way to get the first > > > column > > > > value of a range using GET? > > > > > > > > > > > > -- > > > > Jianshi Huang > > > > > > > > LinkedIn: jianshi > > > > Twitter: @jshuang > > > > Github & Blog: http://huangjs.github.com/ > > > > > > > > > > > > > > > -- > > Jianshi Huang > > > > LinkedIn: jianshi > > Twitter: @jshuang > > Github & Blog: http://huangjs.github.com/ > > > -- Jianshi Huang LinkedIn: jianshi Twitter: @jshuang Github & Blog: http://huangjs.github.com/
