David Ribeiro Alves has posted comments on this change.

Change subject: IMPALA-3857: KuduScanNode race on returning "optional" threads
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Patch Set 1:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/3637/1/be/src/exec/kudu-scan-node.cc
File be/src/exec/kudu-scan-node.cc:

Line 421:   bool optional_threads_exceeded = false;
> I'll take a look, though I'm not too worried about it because it repros con
yeah only if it's easy (not sure how involved is to emulate 
runtime_state_->resource_pool()->optional_exceeded()) but would be good to have 
some coverage that doesn't require running tpch under load.


Line 480:   if (!optional_threads_exceeded) --num_active_scanners_;
> I don't think it's so easy. The issue is that if we don't check the state a
oh, I see the race you are talking about. I'm regretting not having changed the 
goto's from the original implementation and making this more vanilla. Can and 
move mentioning the race to where you decrement num_active_scanners_ in the 
block above and leave a TODO to refactor this logic? this is totally something 
that future me would forget


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Gerrit-MessageType: comment
Gerrit-Change-Id: I22adf2109b43b1b37d9a597de85e063431dff155
Gerrit-PatchSet: 1
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Matthew Jacobs <[email protected]>
Gerrit-Reviewer: David Ribeiro Alves <[email protected]>
Gerrit-Reviewer: Matthew Jacobs <[email protected]>
Gerrit-HasComments: Yes

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