Harish Butani created HIVE-4963:
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Summary: Support in memory PTF partitions
Key: HIVE-4963
URL: https://issues.apache.org/jira/browse/HIVE-4963
Project: Hive
Issue Type: Bug
Components: PTF-Windowing
Reporter: Harish Butani
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.
{noformat}
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
{noformat}
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