SERVER-31456 Set initial{Cluster,Operation}Time in concurrency suite.

Ensures that the FSM worker threads are guaranteed to observe the
effects of the $config.setup() function being called since they'll
specify an afterClusterTime beyond that point.

2 files changed, 38 insertions, 0 deletions

diff --git a/jstests/concurrency/fsm_libs/runner.js b/jstests/concurrency/fsm_libs/runner.js
index 117d1754419..4997a7bf775 100644
--- a/jstests/concurrency/fsm_libs/runner.js
+++ b/jstests/concurrency/fsm_libs/runner.js
@@ -537,6 +537,29 @@ var runner = (function() {
                 cleanup.push(workload);
             });
 
+            // Since the worker threads may be running with causal consistency enabled, we set the
+            // initial clusterTime and initial operationTime for the sessions they'll create so that
+            // they are guaranteed to observe the effects of the workload's $config.setup() function
+            // being called.
+            if (typeof executionOptions.sessionOptions === 'object' &&
+                executionOptions.sessionOptions !== null) {
+                // We only start a session for the worker threads and never start one for the main
+                // thread. We can therefore get the clusterTime and operationTime tracked by the
+                // underlying DummyDriverSession through any DB instance (i.e. the "test" database
+                // here was chosen arbitrarily).
+                const session = cluster.getDB('test').getSession();
+
+                // JavaScript objects backed by C++ objects (e.g. BSON values from a command
+                // response) do not serialize correctly when passed through the ScopedThread
+                // constructor. To work around this behavior, we instead pass a stringified form of
+                // the JavaScript object through the ScopedThread constructor and use eval() to
+                // rehydrate it.
+                executionOptions.sessionOptions.initialClusterTime =
+                    tojson(session.getClusterTime());
+                executionOptions.sessionOptions.initialOperationTime =
+                    tojson(session.getOperationTime());
+            }
+
             if (cluster.shouldPerformContinuousStepdowns()) {
                 cluster.startContinuousFailover();
             }
diff --git a/jstests/concurrency/fsm_libs/worker_thread.js b/jstests/concurrency/fsm_libs/worker_thread.js
index 44bdb870d0c..d03e7393214 100644
--- a/jstests/concurrency/fsm_libs/worker_thread.js
+++ b/jstests/concurrency/fsm_libs/worker_thread.js
@@ -38,6 +38,21 @@ var workerThread = (function() {
                 }
 
                 if (typeof args.sessionOptions !== 'undefined') {
+                    // JavaScript objects backed by C++ objects (e.g. BSON values from a command
+                    // response) do not serialize correctly when passed through the ScopedThread
+                    // constructor. To work around this behavior, we instead pass a stringified form
+                    // of the JavaScript object through the ScopedThread constructor and use eval()
+                    // to rehydrate it.
+                    if (typeof args.sessionOptions.initialClusterTime === 'string') {
+                        args.sessionOptions.initialClusterTime =
+                            eval('(' + args.sessionOptions.initialClusterTime + ')');
+                    }
+
+                    if (typeof args.sessionOptions.initialOperationTime === 'string') {
+                        args.sessionOptions.initialOperationTime =
+                            eval('(' + args.sessionOptions.initialOperationTime + ')');
+                    }
+
                     myDB = new Mongo(args.host)
                                .startSession(args.sessionOptions)
                                .getDatabase(args.dbName);