asterixdb-notifications mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Taewoo Kim (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ASTERIXDB-1556) Hash Table used by External hash group-by doesn't conform to the budget.
Date Wed, 10 Aug 2016 17:32:20 GMT

    [ https://issues.apache.org/jira/browse/ASTERIXDB-1556?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15415632#comment-15415632
] 

Taewoo Kim commented on ASTERIXDB-1556:
---------------------------------------

Sure. We can have a F2F discussion. The reasoning behind this is that the hash table can have
dead spaces as it migrates the old slot to a new place when the slot becomes full. We can
garbage collecting those spaces. And more importantly, the issue of hash table should be dealt
within itself.

> 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.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message