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https://issues.apache.org/jira/browse/HIVE-4963?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13738806#comment-13738806
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Ashutosh Chauhan commented on HIVE-4963:
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Thanks a lot [~rhbutani] for digging into this. Much appreciated. I think this
is the right direction to go. We should eventually get rid of ByteBasedList and
friends and use this approach.
One implementation question I have is why you needed to have PTFRecordWriter,
PTFOutputFormat, PTFInputFormat etc. It seems they don't have any special
logic. Whats the reason we need those and simply cant use
HiveSequenceFileOutFormat and friends.
> 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
> Attachments: HIVE-4963.D11955.1.patch, PTFRowContainer.patch
>
>
> 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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