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https://issues.apache.org/jira/browse/HIVE-16151?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15957494#comment-15957494
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Gopal V commented on HIVE-16151:
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This came up as a ~4% performance in an extra null check, but does allow for
larger hash tables.
LGTM - +1.
> BytesBytesHashTable allocates large arrays
> ------------------------------------------
>
> Key: HIVE-16151
> URL: https://issues.apache.org/jira/browse/HIVE-16151
> Project: Hive
> Issue Type: Bug
> Reporter: Prasanth Jayachandran
> Assignee: Sergey Shelukhin
> Attachments: HIVE-16151.patch
>
>
> These arrays cause GC pressure and also impose key count limitations on the
> table. Wrt the latter, we won't be able to get rid of it without a 64-bit
> hash function, but for now we can get rid of the former. If we need the
> latter we'd add murmur64 and probably account for it differently for resize
> (we don't want to blow up the hashtable by 4 bytes/key in the common case
> where #of keys is less than ~1.5B :))
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