[PIG-1179] Consecutives ORDER BY on the same relation don't work

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Cannot Reproduce
• Affects Version/s: 0.5.0
• Fix Version/s: 0.7.0
• Assignee: Unassigned
• Reporter: Vincent BARAT
• Created: 06/Jan/10 08:34
• Updated: 14/May/10 06:55
• Resolved: 28/Jan/10 00:42

Description

It seems there is a bug in PIG when ORDER BY is used twice on the same relation using ASC and DESC

I have the following script:

imei_start = FOREACH sessions GENERATE imei, start;
imei_starts = GROUP imei_start BY imei;
imei_retained_period = FOREACH imei_starts {
ordered_imei_start = ORDER imei_start BY start DESC;
first_start = LIMIT ordered_imei_start 1;
rev_ordered_imei_start = ORDER imei_start BY start ASC;
last_start = LIMIT rev_ordered_imei_start 1;
GENERATE group, ordered_imei_start, rev_ordered_imei_start;
};

ordered_imei_start and rev_ordered_imei_start are actually the same (they are both sorted in the ASC way) and so last_start is always equal to first_start.

If only one of the 2 ORDER BY is performed, there is no issue.