3 files changed, 78 insertions, 0 deletions
diff --git a/etc/backports_required_for_multiversion_tests.yml b/etc/backports_required_for_multiversion_tests.yml
index fdd3987f44d..aab70423f76 100644
--- a/etc/backports_required_for_multiversion_tests.yml
+++ b/etc/backports_required_for_multiversion_tests.yml
@@ -48,6 +48,8 @@ all:
     test_file: jstests/replsets/step_down_on_secondary.js
   - ticket: SERVER-45010
     test_file: jstests/replsets/rollback_dup_ids_clean_shutdown_during_rollback.js
+  - ticket: SERVER-64184
+    test_file: jstests/noPassthrough/aggregate_metrics.js
   - ticket: SERVER-45906
     test_file: jstests/replsets/trigger_initial_stable_checkpoint.js
   - ticket: SERVER-45178
diff --git a/jstests/noPassthrough/aggregate_metrics.js b/jstests/noPassthrough/aggregate_metrics.js
new file mode 100644
index 00000000000..7a0f0ccc44e
--- /dev/null
+++ b/jstests/noPassthrough/aggregate_metrics.js
@@ -0,0 +1,68 @@
+/**
+ * Tests "metrics.commands.aggregate" counters.
+ */
+
+(function() {
+"use strict";
+
+const mongod = MongoRunner.runMongod();
+const db = mongod.getDB(jsTest.name());
+
+const kAllowDiskUseTrue = "allowDiskUseTrue";
+
+function getAggregateMetrics() {
+    return db.serverStatus().metrics.commands.aggregate;
+}
+
+function getAllowDiskUseAggregateCounter() {
+    return getAggregateMetrics()[kAllowDiskUseTrue];
+}
+
+function testAllowDistUseTrueCounter(coll) {
+    let allowDiskUseTrueValue = getAllowDiskUseAggregateCounter();
+
+    // Make sure that allowDiskUseTrue counter increments by 1 is an aggregate command with
+    // {allowDiskUse: true} is called.
+    assert.eq(0, coll.aggregate([], {allowDiskUse: true}).itcount());
+    allowDiskUseTrueValue += 1;
+    assert.eq(allowDiskUseTrueValue, getAllowDiskUseAggregateCounter());
+
+    // Make sure that allowDiskUseTrue counter stays the same if aggregate command with
+    // {allowDiskUse: false} is called.
+    assert.eq(0, coll.aggregate([], {allowDiskUse: false}).itcount());
+    assert.eq(allowDiskUseTrueValue, getAllowDiskUseAggregateCounter());
+
+    // Make sure that allowDiskUseTrue counter stays the same if aggregate command without
+    // allowDiskUse parameter is called.
+    coll.aggregate([]).itcount();
+    assert.eq(allowDiskUseTrueValue, getAllowDiskUseAggregateCounter());
+
+    // Make sure that allowDiskUseTrue counter increments by 1 is an aggregate command with
+    // {allowDiskUse: true} is called a second time.
+    assert.eq(0, coll.aggregate([], {allowDiskUse: true}).itcount());
+    allowDiskUseTrueValue += 1;
+    assert.eq(allowDiskUseTrueValue, getAllowDiskUseAggregateCounter());
+}
+
+// Execute aggregate command to ensure that the metrics.
+assert.eq(0, db.coll.aggregate([]).itcount());
+
+// Check if the metrics.commands.aggregate.allowDiskUse exists and by default equals to 0.
+assert(getAggregateMetrics().hasOwnProperty(kAllowDiskUseTrue));
+assert.eq(0, getAllowDiskUseAggregateCounter());
+
+// Test on a collection.
+const simpleTableName = "aggregateMetricsTest";
+const simpleColl = db[simpleTableName];
+simpleColl.drop();
+testAllowDistUseTrueCounter(simpleColl);
+
+// Test on a view.
+const simpleViewName = "viewOnAggregateMetricsTest";
+const simpleView = db[simpleViewName];
+simpleView.drop();
+assert.commandWorked(db.createView(simpleViewName, simpleTableName, [{$match: {a: 1}}]));
+testAllowDistUseTrueCounter(simpleView);
+
+MongoRunner.stopMongod(mongod);
+})();
diff --git a/src/mongo/db/commands/run_aggregate.cpp b/src/mongo/db/commands/run_aggregate.cpp
index 775b3047158..b93d81708bf 100644
--- a/src/mongo/db/commands/run_aggregate.cpp
+++ b/src/mongo/db/commands/run_aggregate.cpp
@@ -86,6 +86,10 @@ using std::unique_ptr;
 using stdx::make_unique;
 
 namespace {
+Counter64 allowDiskUseCounter;
+ServerStatusMetricField<Counter64> allowDiskUseMetric{"commands.aggregate.allowDiskUseTrue",
+                                                      &allowDiskUseCounter};
+
 /**
  * Returns true if this PlanExecutor is for a Pipeline.
  */
@@ -655,6 +659,10 @@ Status runAggregate(OperationContext* opCtx,
         auto pipeline = uassertStatusOK(Pipeline::parse(request.getPipeline(), expCtx));
         expCtx->stopExpressionCounters();
 
+        if (request.shouldAllowDiskUse()) {
+            allowDiskUseCounter.increment();
+        }
+
         // Check that the view's collation matches the collation of any views involved in the
         // pipeline.
         if (!pipelineInvolvedNamespaces.empty()) {