SERVER-37156 Wait for worker threads to exit in benchRun().

(cherry picked from commit 12dba1e5b8c5ec7532da1bfa2e05c56f021d7f06)

2 files changed, 15 insertions, 2 deletions

diff --git a/src/mongo/shell/bench.cpp b/src/mongo/shell/bench.cpp
index 4a56968f15f..34fb3fa4bf6 100644
--- a/src/mongo/shell/bench.cpp
+++ b/src/mongo/shell/bench.cpp
@@ -744,10 +744,20 @@ BenchRunWorker::BenchRunWorker(size_t id,
                                int64_t randomSeed)
     : _id(id), _config(config), _brState(brState), _randomSeed(randomSeed) {}
 
-BenchRunWorker::~BenchRunWorker() = default;
+BenchRunWorker::~BenchRunWorker() {
+    try {
+        // We explicitly call join() on the started thread to ensure that any thread-local variables
+        // (e.g. 'currentClient' when running through mongoebench) have been destructed before
+        // returning from BenchRunWorker's destructor.
+        _thread.join();
+    } catch (...) {
+        severe() << "caught exception in destructor: " << exceptionToStatus();
+        std::terminate();
+    }
+}
 
 void BenchRunWorker::start() {
-    stdx::thread([this] { run(); }).detach();
+    _thread = stdx::thread([this] { run(); });
 }
 
 bool BenchRunWorker::shouldStop() const {
diff --git a/src/mongo/shell/bench.h b/src/mongo/shell/bench.h
index fb4618d4160..1f61b2e96f5 100644
--- a/src/mongo/shell/bench.h
+++ b/src/mongo/shell/bench.h
@@ -38,6 +38,7 @@
 #include "mongo/platform/atomic_word.h"
 #include "mongo/stdx/condition_variable.h"
 #include "mongo/stdx/mutex.h"
+#include "mongo/stdx/thread.h"
 #include "mongo/util/timer.h"
 
 namespace pcrecpp {
@@ -477,6 +478,8 @@ private:
     /// Predicate, used to decide whether or not it's time to collect statistics
     bool shouldCollectStats() const;
 
+    stdx::thread _thread;
+
     const size_t _id;
 
     const BenchRunConfig* _config;