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https://issues.apache.org/jira/browse/ASTERIXDB-1556?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15418016#comment-15418016
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Michael J. Carey commented on ASTERIXDB-1556:
---------------------------------------------

Semi-agreed - but - if this is a PartitionedFramedHashTable (vs. a more vanilla 
FramedHashTable) with the notion of partitions that are bulk-reset - then this 
would be a natural thing to do when resetting a partition.  HOWEVER: Given how 
stuff is laid out, I'm not sure garbage collection is easily done on a 
per-partition basis (without having separate hash tables per partition)?  
Anyway, I'm in favor of whatever turns out to get as much space back as 
possible as often as possible while not slowing down the normal case. :-)

> Hash Table used by External hash group-by doesn't conform to the budget.
> ------------------------------------------------------------------------
>
>                 Key: ASTERIXDB-1556
>                 URL: https://issues.apache.org/jira/browse/ASTERIXDB-1556
>             Project: Apache AsterixDB
>          Issue Type: Bug
>            Reporter: Taewoo Kim
>            Assignee: Taewoo Kim
>         Attachments: 2wayjoin.pdf, 2wayjoin.rtf, 2wayjoinplan.rtf, 
> 3wayjoin.pdf, 3wayjoin.rtf, 3wayjoinplan.rtf
>
>
> When we enable prefix-based fuzzy-join and apply the multi-way fuzzy-join ( > 
> 2), the system generates an out-of-memory exception. 
> Since a fuzzy-join is created using 30-40 lines of AQL codes and this AQL is 
> translated into massive number of operators (more than 200 operators in the 
> plan for a 3-way fuzzy join), it could generate out-of-memory exception.
> /// Update: as the discussion goes, we found that hash table in the external 
> hash group by doesn't conform to the frame limit. So, an out of memory 
> exception happens during the execution of an external hash group by operator.



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