> but it still seem a bit strange coming from years and years of sql. Think of the composite column name as a composite key. You want to write an efficient query that uses a seek and partial scan of the index b-tree, rather than a full scan. > split this CF into two? Or change the order of the column components as suggested.
Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 16/02/2012, at 9:16 PM, Deno Vichas wrote: > thanks for the reply. i understand why, but it still seem a bit strange > coming from years and years of sql. so if i want to avoid the extra load > from fetching way more than i needed would i be best off split this CF into > two? > > thanks, > deno > > On 2/13/2012 10:41 AM, aaron morton wrote: >> >> My understanding is you expected to see >> >> 111:ticks >> 222:ticks >> 333:ticks >> 444:ticks >> >> But instead you are getting >> >> 111:ticks >> 111:quote >> 222:ticks >> 222:quote >> 333:ticks >> 333:quote >> 444:ticks >> >> If that is the case things are working as expected. >> >> The slice operation gets a column range. So if you start at 111:ticks and >> end at 444:ticks you are asking for all the column in between. >> >> it is not possible to filter at each level of a composite column. >> >> Hope that helps. >> >> ----------------- >> Aaron Morton >> Freelance Developer >> @aaronmorton >> http://www.thelastpickle.com >> >> On 10/02/2012, at 10:58 PM, Deno Vichas wrote: >> >>> all, >>> >>> could somebody clue me to why the below code doesn't work. my schema is; >>> >>> create column family StockHistory >>> with comparator = 'CompositeType(LongType,UTF8Type)' >>> and default_validation_class = 'UTF8Type' >>> and key_validation_class = 'UTF8Type'; >>> >>> >>> the time part works but i'm getting other column with the second half not >>> equaling the value set. it's like it's ignoring the string part of the >>> composite. >>> >>> Composite start = new Composite(); >>> Composite end = new Composite(); >>> start.addComponent(0, >>> startDate.toDateTimeAtStartOfDay().toDate().getTime(), >>> Composite.ComponentEquality.EQUAL); >>> end.addComponent(0, endDate.toDateMidnight().toDate().getTime(), >>> Composite.ComponentEquality.EQUAL); >>> >>> start.addComponent(1, "ticks", Composite.ComponentEquality.EQUAL); >>> end.addComponent(1, "ticks", >>> Composite.ComponentEquality.GREATER_THAN_EQUAL); >>> >>> SliceQuery<String, Composite, String> sliceQuery = >>> HFactory.createSliceQuery(_keyspace, _stringSerializer, new >>> CompositeSerializer(), _stringSerializer); >>> sliceQuery.setColumnFamily(CF_STOCK_HISTORY).setKey(symbol); >>> sliceQuery.setRange(start, end, false, 10); >>> >>> QueryResult<ColumnSlice<Composite, String>> result = >>> sliceQuery.execute(); >>> ColumnSlice<Composite, String> cs = result.get(); >>> SortedSet<String> historyJSON = new TreeSet<String>(); >>> for ( HColumn<Composite, String> col: cs.getColumns() ) { >>> System.out.println(col.getName().get(0, _longSerializer) +"|"+ >>> col.getName().get(1,StringSerializer.get())); >>> } >>> >>> >>> this outputs the following; >>> >>> 1327035600000|ticks >>> 1327046400000|quote >>> 1327294800000|ticks >>> 1327305600000|quote >>> 1327381200000|ticks >>> 1327392000000|quote >>> 1327467600000|ticks >>> 1327478400000|quote >>> 1327554000000|ticks >>> 1327564800000|quote >>> >>> thanks, >>> deno >> >
