Matthew Jacobs has posted comments on this change.

Change subject: IMPALA-3857: KuduScanNode race on returning "optional" threads
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Patch Set 2:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/3637/2/be/src/exec/kudu-scan-node.cc
File be/src/exec/kudu-scan-node.cc:

PS2, Line 451: num_active_scanners_ > 1
> Turns out it leads to a deadlock if we take lock_ and then ReleaseThreadTok
I tried splitting lock_ up to have a separate lock for this scenario, to make 
sure multiple threads don't exit here at the same time. That didn't work 
because other threads could exit for other reasons. At that point it felt like 
it was getting too complicated so I think it may just best to have this 
redundancy for now. When we improve the ThreadResourceMgr this could get 
easier. I added a TODO about it.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I22adf2109b43b1b37d9a597de85e063431dff155
Gerrit-PatchSet: 2
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Matthew Jacobs <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: David Ribeiro Alves <[email protected]>
Gerrit-Reviewer: Matthew Jacobs <[email protected]>
Gerrit-HasComments: Yes

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