Hi all,
I am porting custom MR code to Hive and have written working UDFs
where I need them. Is there a work around to having to do this in
Hive:
select * from
(
select name_id, toTileX(longitude,0) as x, toTileY(latitude,0) as
y, 0 as zoom, funct2(lontgitude, 0) as f2_x, funct2(latitude,0) as
f2_y, count (1) as count
from table
group by name_id, x, y, f2_x, f2_y
UNION ALL
select name_id, toTileX(longitude,1) as x, toTileY(latitude,1) as
y, 1 as zoom, funct2(lontgitude, 1) as f2_x, funct2(latitude,1) as
f2_y, count (1) as count
from table
group by name_id, x, y, f2_x, f2_y
--- etc etc increasing in zoom
)
The issue being that this does many passes over the table, whereas
previously in my Map() I would just emit many times from the same
input record and then let it all group in the shuffle and sort.
I actually emit 184 times for an input record (23 zoom levels of
google maps, and 8 ways to derive the name_id) for a single record
which means 184 union statements - Is it possible in hive to force it
to emit many times from the source record in the stage-1 map?
(ahem) Does anyone know if Pig can do this if not in Hive?
I hope I have explained this well enough to make sense.
Thanks in advance,
Tim
