[HIVE-7397] Set the default threshold for fetch task conversion to 1Gb

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.13.1, 0.14.0
• Fix Version/s: 0.14.0
• Labels: Performance
• Release Note: Set the simple fetch task conversion to "more" with a default threshold of 1Gb
• Assignee: Gopal Vijayaraghavan
• Reporter: Gopal Vijayaraghavan
• Created: 12/Jul/14 05:48
• Updated: 11/Jan/15 09:02
• Resolved: 23/Jul/14 15:12

Description

Currently, modifying the value of hive.fetch.task.conversion to "more" results in a dangerous setting where small scale queries function, but large scale queries crash.

This occurs because the default threshold of -1 means apply this optimization for a petabyte table.

I am testing a variety of queries with the setting "more" (to make it the default option as suggested by HIVE-887) change the default threshold for this feature to a reasonable 1Gb.