[HIVE-887] Allow SELECT <col> without a mapreduce job

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.10.0

Environment

All

• Release Note: Set hive-conf hive.fetch.task.conversion to more to make use of this feature. Turned-off by default.
• Assignee: Ning Zhang
• Reporter: Eric Sun
• Created: 19/Oct/09 16:35
• Updated: 06/Mar/14 08:32
• Resolved: 11/Dec/12 16:38

Description

I often find myself needing to take a quick look at a particular column of a Hive table.

I usually do this by doing a
SELECT * from <table> LIMIT 20;
from the CLI. Doing this is pretty fast since it doesn't require a mapreduce job. However, it's tough to examine just 1 or 2 columns when the table is very wide.

So, I might do
SELECT <col> from <table> LIMIT 20;
but it's much slower since it requires a map-reduce. It'd be really convenient if a map-reduce wasn't necessary.

Currently a good work around is to do
hive -e "select * from table" | cut --key=n
but it'd be more convenient if it were built in since it alleviates the need for column counting.

Issue Links

• is duplicated by: HIVE-2925 Support non-MR fetching for simple queries with select/limit/filter operations only