An important bit to read about supercolumn limitations:
http://www.riptano.com/docs/0.6/data_model/supercolumns#limitations
Don't make supercolumns with a huge number of subcolumns (or a few really
large subcolumns) unless you plan to always read all of them at once.
- Tyler
On Fri, Jan 7, 2011 at 1:27 AM, Arijit Mukherjee <ariji...@gmail.com> wrote:
> Thanx to both of you. I can now go ahead a bit more.
>
> Arijit
>
> On 7 January 2011 12:53, Narendra Sharma <narendra.sha...@gmail.com>
> wrote:
> > With raw thrift APIs:
> >
> > 1. Fetch column from supercolumn:
> >
> > ColumnPath cp = new ColumnPath("ColumnFamily");
> > cp.setSuper_column("SuperColumnName");
> > cp.setColumn("ColumnName");
> > ColumnOrSuperColumn resp = client.get(getByteBuffer("RowKey"), cp,
> > ConsistencyLevel.ONE);
> > Column c = resp.getColumn();
> >
> > 2. Add a new supercolumn:
> >
> > SuperColumn superColumn = new SuperColumn();
> > superColumn.setName(getBytes("SuperColumnName"));
> > cols = new ArrayList<Column>();
> > Column c = new Column();
> > c.setName(name);
> > c.setValue(value);
> > c.setTimestamp(timeStamp);
> > cols.add(c);
> > //repeat above 5 lines for as many cols you want in supercolumn
> > superColumn.setColumns(cols);
> >
> >
> > List<Mutation> mutations = new ArrayList<Mutation>();
> > ColumnOrSuperColumn csc = new ColumnOrSuperColumn();
> > csc.setSuper_column(superColumn);
> > csc.setSuper_columnIsSet(true);
> > Mutation m = new Mutation();
> > m.setColumn_or_supercolumn(csc);
> > m.setColumn_or_supercolumnIsSet(true);
> > mutations.add(m);
> >
> >
> > Map<String, List<Mutation>> allMutations = new HashMap<String,
> > List<Mutation>>();
> > allMutations.put("ColumnFamilyName", mutations);
> > Map<ByteBuffer, Map<String, List<Mutation>>> mutationMap = new
> > HashMap<ByteBuffer, Map<String, List<Mutation>>>();
> > mutationMap.put(getByteBuffer("RowKey"), mutations);
> > client.batch_mutate(mutationMap, ConsistencyLevel.ONE);
> >
> > HTH!
> >
> > Thanks,
> > Naren
> >
> >
> >
> > On Thu, Jan 6, 2011 at 10:42 PM, Arijit Mukherjee <ariji...@gmail.com>
> > wrote:
> >>
> >> Thank you. And is it similar if I want to search a subcolumn within a
> >> given supercolumn? I mean I have the supercolumn key and the subcolumn
> >> key - can I fetch the particular subcolumn?
> >>
> >> Can you share a small piece of example code for both?
> >>
> >> I'm still new into this and trying to figure out the Thrift APIs. I
> >> attempted to use Hector, but got myself into more confusion.
> >>
> >> Arijit
> >>
> >> On 7 January 2011 11:44, Roshan Dawrani <roshandawr...@gmail.com>
> wrote:
> >> >
> >> > On Fri, Jan 7, 2011 at 11:39 AM, Arijit Mukherjee <ariji...@gmail.com
> >
> >> > wrote:
> >> >>
> >> >> Hi
> >> >>
> >> >> I've a quick question about supercolumns.
> >> >> EventRecord = {
> >> >> eventKey2: {
> >> >> e2-ts1: {set of columns},
> >> >> e2-ts2: {set of columns},
> >> >> ...
> >> >> e2-tsn: {set of columns}
> >> >> }
> >> >> ....
> >> >> }
> >> >>
> >> >> If I want to append another "e2-tsp: {set of columns}" to the event
> >> >> record keyed by eventKey2, do I need to retrieve the entire eventKey2
> >> >> map, and then append this new row and re-insert eventKey2?
> >> >
> >> > No, you can simply insert a new super column with its sub-columns with
> >> > the rowKey that you want, and it will join the other super columns of
> that
> >> > row.
> >> >
> >> > A row have billions of super columns. Imagine fetching them all, just
> to
> >> > add one more super column into it.
> >> >
> >> >
> >> >
> >> >
> >> >
> >>
> >>
> >> --
> >> "And when the night is cloudy,
> >> There is still a light that shines on me,
> >> Shine on until tomorrow, let it be."
> >
> >
>
>
>
> --
> "And when the night is cloudy,
> There is still a light that shines on me,
> Shine on until tomorrow, let it be."
>
