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https://issues.apache.org/jira/browse/PIG-1973?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13022584#comment-13022584
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Woody Anderson commented on PIG-1973:
-------------------------------------
incorrect.
initialValue is invoked when get() is first called. However, in the old code,
initialValue returns null b/c it was not overridden.
thus, if 2 threads call getUDFContext() at the same time they may get 2
different UDFContext objects, b/c the method
does an unprotected comparison/set check:
{code}
public static UDFContext getUDFContext() {
if (tss.get() == null) {
UDFContext ctx = new UDFContext();
tss.set(ctx);
}
return tss.get();
}
{code}
this is CLASSIC race condition.
> UDFContext.getUDFContext has a thread race condition around it's ThreadLocal
> ----------------------------------------------------------------------------
>
> Key: PIG-1973
> URL: https://issues.apache.org/jira/browse/PIG-1973
> Project: Pig
> Issue Type: Bug
> Components: impl
> Affects Versions: 0.8.0, 0.9.0
> Reporter: Woody Anderson
> Assignee: Woody Anderson
> Priority: Minor
> Fix For: 0.9.0
>
> Attachments: 1973.patch
>
>
> this is probably isn't manifesting anywhere, but it's an incorrect use of the
> ThreadLocal pattern.
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