[HIVE-4963] Support in memory PTF partitions

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.12.0
• Component/s: PTF-Windowing
• Labels: TODOC12
• Assignee: Harish Butani
• Reporter: Harish Butani
• Created: 31/Jul/13 05:16
• Updated: 12/Nov/14 01:54
• Resolved: 25/Aug/13 07:52

Description

PTF partitions apply the defensive mode of assuming that partitions will not fit in memory. Because of this there is a significant deserialization overhead when accessing elements.

Allow the user to specify that there is enough memory to hold partitions through a 'hive.ptf.partition.fits.in.mem' option.

Savings depends on partition size and in case of windowing the number of UDAFs and the window ranges. For eg for the following (admittedly extreme) case the PTFOperator exec times went from 39 secs to 8 secs.

select t, s, i, b, f, d,
min(t) over(partition by 1 rows between unbounded preceding and current row), 
min(s) over(partition by 1 rows between unbounded preceding and current row), 
min(i) over(partition by 1 rows between unbounded preceding and current row), 
min(b) over(partition by 1 rows between unbounded preceding and current row) 
from over10k

Issue Links

• is required by: HIVE-4964 Cleanup PTF code: remove code dealing with non standard sql behavior we had original introduced