[impala] branch master updated: IMPALA-10047: Revert core piece of IMPALA-6984

[jo...@apache.org]

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joemcdonnell pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/impala.git


The following commit(s) were added to refs/heads/master by this push:
     new c413f9b  IMPALA-10047: Revert core piece of IMPALA-6984
c413f9b is described below

commit c413f9b558d51de877f497590baf14139ad5cf99
Author: Joe McDonnell <jo...@cloudera.com>
AuthorDate: Tue Aug 4 17:29:19 2020 -0700

    IMPALA-10047: Revert core piece of IMPALA-6984
    
    Performance testing on TPC-DS found a peformance regression
    on short queries due to delayed exec status reports. Further
    testing traced this back to IMPALA-6984's behavior of
    cancelling backends on EOS. The coordinator log show that
    CancelBackends() call intermittently taking 10 seconds due
    to timing out in the RPC layer.
    
    As a temporary workaround, this reverts the core part of
    IMPALA-6984 that added that CancelBackends() call for EOS.
    It leaves the rest of IMPALA-6984 intact, as other code has built
    on top of it.
    
    Testing:
     - Core job
     - Performance tests
    
    Change-Id: Ibf00a56e91f0376eaaa552e3bb4763501bfb49e8
    (cherry picked from commit b91f3c0e064d592f3cdf2a2e089ca6546133ba55)
    Reviewed-on: http://gerrit.cloudera.org:8080/16288
    Reviewed-by: Joe McDonnell <jo...@cloudera.com>
    Tested-by: Impala Public Jenkins <im...@cloudera.com>
---
 be/src/runtime/coordinator.cc | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/be/src/runtime/coordinator.cc b/be/src/runtime/coordinator.cc
index b57d66f..0ceae83 100644
--- a/be/src/runtime/coordinator.cc
+++ b/be/src/runtime/coordinator.cc
@@ -714,9 +714,7 @@ void Coordinator::HandleExecStateTransition(
   // execution and release resources.
   ReleaseExecResources();
   if (new_state == ExecState::RETURNED_RESULTS) {
-    // Cancel all backends, but wait for the final status reports to be received so that
-    // we have a complete profile for this successful query.
-    CancelBackends(/*fire_and_forget=*/ false);
+    // TODO: IMPALA-6984: cancel all backends in this case too.
     WaitForBackends();
   } else {
     CancelBackends(/*fire_and_forget=*/ true);