Tim Armstrong has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/14539 )

Change subject: IMPALA-8995: Fix synchronization in dequeue thread
......................................................................


Patch Set 1:

(1 comment)

Fix makes sense, just want to be sure that we're not leaving things in a state 
where more subtle bugs will go un-noticed.

http://gerrit.cloudera.org:8080/#/c/14539/1/be/src/scheduling/admission-controller.cc
File be/src/scheduling/admission-controller.cc:

http://gerrit.cloudera.org:8080/#/c/14539/1/be/src/scheduling/admission-controller.cc@1375
PS1, Line 1375:     dequeue_cv_.Wait(lock);
I feel like this usage pattern of condition variables is really asking for 
trouble - the pattern of

  while (!condition) {
    cv_.wait(lock);
  }

Is a lot more robust. Can we switch to using this pattern so that it's more 
explicit, e.g. have a pending_dequeue_ variable that is explicitly set when 
signalling the variable to make sure that the wakeup doesn't get lost.



--
To view, visit http://gerrit.cloudera.org:8080/14539
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I91080ce54e59cc7e6361f7c50d6b2156a8a180c8
Gerrit-Change-Number: 14539
Gerrit-PatchSet: 1
Gerrit-Owner: Bikramjeet Vig <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Comment-Date: Thu, 24 Oct 2019 01:10:19 +0000
Gerrit-HasComments: Yes

Reply via email to