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https://issues.apache.org/jira/browse/PIG-40?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12551137
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Benjamin Reed commented on PIG-40:
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The plan is to use Sam's idea to monitor memory usage and then invoke spill()
on big bags when memory gets low. See PIG-30 for documentation of the spill
hook being added by Alan.
> Memory management in BigDataBag is probably wrong
> -------------------------------------------------
>
> Key: PIG-40
> URL: https://issues.apache.org/jira/browse/PIG-40
> Project: Pig
> Issue Type: Bug
> Components: impl
> Reporter: Sam Pullara
> Assignee: Benjamin Reed
> Attachments: BigDataBag.java, MemoryUsage.java
>
>
> src/org/apache/pig/data/BigDataBag.java
> 1) You should not use finalizers for things other than external resources --
> using them here is very dangerous and could inadvertantly lead to deadlocks
> and object resurrection and just decreases performance without any advantage.
> 2) Using .freeMemory() the way it is used in this class is broken.
> freeMemory() is going to return a mostly random number between 0 and the real
> amount. Adding gc() in here is a terrible performance burden. If you really
> want to do something like this you should using softreferences and
> finalization queues.
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