A couple of alternatives off the top of my head: 1) A row of supercolumns becomes a row of standard columns with compound column names.
2) A row of N supercolumns becomes N rows of standard columns (with compound keys if needed); a separate timeline or index replaces the super column names. There might be other data models that work for a specific case, as well. - Tyler On Sat, Jan 8, 2011 at 3:38 AM, Rajkumar Gupta <rajkumar....@gmail.com>wrote: > Thanks Tyler & Stu, > > Tyler, as the alternatives for large no of subcolumns in a > supercolumn, what do you suggest ? Like splitting up a > 'supercolumnFamily' into several 'columnfamilies' ?? What else ? > > > On Sat, Jan 8, 2011 at 2:33 PM, Stu Hood <stuh...@gmail.com> wrote: > > Raj: the super column indexing is a longstanding issue that we've been > > considering recently, and would like to fix. > > See https://issues.apache.org/jira/browse/CASSANDRA-674 > > > > On Fri, Jan 7, 2011 at 10:53 PM, Tyler Hobbs <ty...@riptano.com> wrote: > >> > >> Not that I'm aware of. There are several other decent alternatives to > >> large amounts of subcolumns in a supercolumn, so I don't think it's a > high > >> priority. > >> > >> - Tyler > >> > >> On Fri, Jan 7, 2011 at 9:59 PM, Rajkumar Gupta <rajkumar....@gmail.com> > >> wrote: > >>> > >>> Hey Tyler, > >>> > >>> Is this limitation of supercolumns going to be removed anytime sooner ? > >>> > >>> Raj > >>> > >>> On Fri, Jan 7, 2011 at 8:51 PM, Tyler Hobbs <ty...@riptano.com> wrote: > >>> > 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." > >>> > > >>> > > >> > > > > >
