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https://issues.apache.org/jira/browse/PIG-40?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12547177
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Benjamin Reed commented on PIG-40:
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No, we need to delete in finalize() since we will no longer be using those
files once the BigDataBag is GCed. If we relied on File.deleteOnExit we may end
up exhausting disk space in tasks with lots of bags that spill to disk.
As you say, finalizers are for freeing up external resources associated with an
object. The temp spill files are such external resources.
> 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
>
> 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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