just to correct myself: to sort timeUUID on column in descending order, sliceRange.setReversed(true) does the trick. -aj
On Sun, May 9, 2010 at 9:07 AM, AJ Chen <ajc...@web2express.org> wrote: > true, i think. > but don't rush to OrderPreservingPartitioners. it may be better to create > another key CF for sorting the key (put the key in column, which is sorted > automatically). to paginate through the records, you get a sorted slice of > keys from the key CF, and then look up the record CF with each key. > > One issue i found with the default column sorting is that the timeUUIDType > sorts time-uuid column in ascending order instead of descending order. > get_slice call returns oldest time-uuid instead of most recent time-uuid. Is > this a bug? normally, you want get_slice returns most recent timeuuid, > which make function like "get most recent 10 records" easy. > > -aj > > > On Sun, May 9, 2010 at 12:00 AM, David Boxenhorn <da...@lookin2.com>wrote: > >> This is something that I'm not sure that I understand. Can somebody >> confirm/deny that I understand it? Thanks. >> >> If you use random partitioning, you can loop through all keys with a range >> query, but they will not be sorted. >> >> True or False? >> >> On Sat, May 8, 2010 at 3:45 AM, AJ Chen <ajc...@web2express.org> wrote: >> >>> thanks, that works. -aj >>> >>> >>> On Fri, May 7, 2010 at 1:17 PM, Stu Hood <stu.h...@rackspace.com> wrote: >>> >>>> Your IPartitioner implementation decides how the row keys are sorted: >>>> see http://wiki.apache.org/cassandra/StorageConfiguration#Partitioner . >>>> You need to be using one of the OrderPreservingPartitioners if you'd like a >>>> reasonable order for the keys. >>>> >>>> -----Original Message----- >>>> From: "AJ Chen" <ajc...@web2express.org> >>>> Sent: Friday, May 7, 2010 3:10pm >>>> To: user@cassandra.apache.org >>>> Subject: key is sorted? >>>> >>>> I have a super column family for "topic", key being the name of the >>>> topic. >>>> <ColumnFamily Name="Topic" CompareWith="UTF8Type" ColumnType="Super" >>>> CompareSubcolumnsWith="BytesType" /> >>>> When I retrieve the rows, the rows are not sorted by the key. Is the row >>>> key >>>> sorted in cassandra by default? >>>> >>>> -aj >>>> -- >>>> AJ Chen, PhD >>>> Chair, Semantic Web SIG, sdforum.org >>>> http://web2express.org >>>> twitter @web2express >>>> Palo Alto, CA, USA >>>> >>>> >>>> >>> >>> >>> -- >>> AJ Chen, PhD >>> Chair, Semantic Web SIG, sdforum.org >>> http://web2express.org >>> twitter @web2express >>> Palo Alto, CA, USA >>> >> >> > > > -- > AJ Chen, PhD > Chair, Semantic Web SIG, sdforum.org > http://web2express.org > twitter @web2express > Palo Alto, CA, USA > -- AJ Chen, PhD Chair, Semantic Web SIG, sdforum.org http://web2express.org twitter @web2express Palo Alto, CA, USA
