Just a bit saying whether the record was present or null. Note that this is strictly more expressive than the Parquet's format in that it can encode structures with all null values. I believe the Parquet encoder would discard a row of the form (null, null) since it wouldn't have any leaves to make it materialize.
-- Owen On Wed, Apr 10, 2013 at 3:48 PM, Ted Dunning <[email protected]> wrote: > On Wed, Apr 10, 2013 at 10:17 AM, Owen O'Malley <[email protected]> > wrote: > > > Ted, > > ORC does support nested structures and splits them into primitive > > columns. > > > Good to hear. > > > > ... > > create table Foo ( > > complex: struct<field1: int, field2: map<string, int>> > > simple: timestamp > > ); > > > > will end up with a prefix-order flattening of the columns: > > > > columns: > > 0 - top level record (struct, children: 1, 6) > > 1 - complex (struct, children: 2, 3) > > > > What is stored in column 1? >
