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From: todd@apache.org
To: commits@kudu.apache.org
Date: Thu, 06 Oct 2016 00:06:00 -0000
Message-Id: <7357ba24a9f541fba2d38546f99670d9@git.apache.org>
In-Reply-To: <bac091cab5734b079745493e035582a9@git.apache.org>
References: <bac091cab5734b079745493e035582a9@git.apache.org>
Subject: [4/8] kudu git commit: maintenance_manager-test: fix flaky test
archived-at: Thu, 06 Oct 2016 00:05:59 -0000

maintenance_manager-test: fix flaky test

TestCompletedOps failed relatively often because of the following racy
interleaving:

- Multiple MM threads called Prepare() while remaining_runs_ was positive
- These threads then called Perform(), which decremented remaining_runs_
  once per thread. This resulted in the op being called more times than
  'remaining_runs_', causing an assertion failure.

The fix is to separately count the number of 'prepared' ops.

Change-Id: I003e72339f69228195130c89572a20be3009f22c
Reviewed-on: http://gerrit.cloudera.org:8080/4634
Reviewed-by: Jean-Daniel Cryans <jdcryans@apache.org>
Tested-by: Kudu Jenkins


Project: http://git-wip-us.apache.org/repos/asf/kudu/repo
Commit: http://git-wip-us.apache.org/repos/asf/kudu/commit/07ce9fbc
Tree: http://git-wip-us.apache.org/repos/asf/kudu/tree/07ce9fbc
Diff: http://git-wip-us.apache.org/repos/asf/kudu/diff/07ce9fbc

Branch: refs/heads/master
Commit: 07ce9fbce4fcdcfafe01db0347b69c0283df5e2c
Parents: 4db8851
Author: Todd Lipcon <todd@apache.org>
Authored: Wed Oct 5 14:37:50 2016 -0700
Committer: Todd Lipcon <todd@apache.org>
Committed: Wed Oct 5 22:26:33 2016 +0000

----------------------------------------------------------------------
 src/kudu/util/maintenance_manager-test.cc | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/kudu/blob/07ce9fbc/src/kudu/util/maintenance_manager-test.cc
----------------------------------------------------------------------
diff --git a/src/kudu/util/maintenance_manager-test.cc b/src/kudu/util/maintenance_manager-test.cc
index 2448766..cb124af 100644
--- a/src/kudu/util/maintenance_manager-test.cc
+++ b/src/kudu/util/maintenance_manager-test.cc
@@ -86,6 +86,7 @@ class TestMaintenanceOp : public MaintenanceOp {
       maintenance_op_duration_(METRIC_maintenance_op_duration.Instantiate(metric_entity_)),
       maintenance_ops_running_(METRIC_maintenance_ops_running.Instantiate(metric_entity_, 0)),
       remaining_runs_(1),
+      prepared_runs_(0),
       sleep_time_(MonoDelta::FromSeconds(0)) {
   }
 
@@ -96,6 +97,8 @@ class TestMaintenanceOp : public MaintenanceOp {
     if (remaining_runs_ == 0) {
       return false;
     }
+    remaining_runs_--;
+    prepared_runs_++;
     DLOG(INFO) << "Prepared op " << name();
     return true;
   }
@@ -104,8 +107,11 @@ class TestMaintenanceOp : public MaintenanceOp {
     {
       std::lock_guard<Mutex> guard(lock_);
       DLOG(INFO) << "Performing op " << name();
-      CHECK_GE(remaining_runs_, 1);
-      remaining_runs_--;
+
+      // Ensure that we don't call Perform() more times than we returned
+      // success from Prepare().
+      CHECK_GE(prepared_runs_, 1);
+      prepared_runs_--;
     }
 
     SleepFor(sleep_time_);
@@ -166,6 +172,8 @@ class TestMaintenanceOp : public MaintenanceOp {
   // The number of remaining times this operation will run before disabling
   // itself.
   int remaining_runs_;
+  // The number of Prepared() operations which have not yet been Perform()ed.
+  int prepared_runs_;
 
   // The amount of time each op invocation will sleep.
   MonoDelta sleep_time_;