note: this is somewhat a repost of something i posted on the CDH3 user group. apologies if that is not appropriate.
i am exploring map-joins in hive. with hive.auto.convert.join=true hive tries to do a map-join and then falls back on a mapreduce-join if certain conditions are not met. this sounds great. but when i do a query and i notice it falls back on a mapreduce-join, how can i see which condition triggered the fallback (smalltablle.filesize or mapjoin.maxsize or something else perhaps memory related)? i tried reading the default log that a hive session produces, but it seems more like a massive json file than a log to me, so it is very hard for me to interpret that. i also turned on logging to console with debugging, looking for any clues there but without luck so far. is the info there and am i just overlooking it? any ideas? thanks! koert
