SERVER-69553 Add a way to retrieve the total number tasks registered on the range deleter service

3 files changed, 35 insertions, 0 deletions

diff --git a/src/mongo/db/s/range_deleter_service.cpp b/src/mongo/db/s/range_deleter_service.cpp
index 80c25e6de85..5c111641345 100644
--- a/src/mongo/db/s/range_deleter_service.cpp
+++ b/src/mongo/db/s/range_deleter_service.cpp
@@ -204,6 +204,16 @@ BSONObj RangeDeleterService::dumpState() {
     return builder.obj();
 }
 
+long long RangeDeleterService::totalNumOfRegisteredTasks() {
+    auto lock = _acquireMutexUnconditionally();
+
+    long long counter = 0;
+    for (const auto& [collUUID, ranges] : _rangeDeletionTasks) {
+        counter += ranges.size();
+    }
+    return counter;
+}
+
 SharedSemiFuture<void> RangeDeleterService::registerTask(
     const RangeDeletionTask& rdt,
     SemiFuture<void>&& waitForActiveQueriesToComplete,
diff --git a/src/mongo/db/s/range_deleter_service.h b/src/mongo/db/s/range_deleter_service.h
index 33144c3f190..a946865739c 100644
--- a/src/mongo/db/s/range_deleter_service.h
+++ b/src/mongo/db/s/range_deleter_service.h
@@ -152,6 +152,11 @@ public:
      */
     BSONObj dumpState();
 
+    /*
+     * Returns the total number of range deletion tasks registered on the service.
+     */
+    long long totalNumOfRegisteredTasks();
+
 private:
     /* Asynchronously register range deletions on the service. To be called on on step-up */
     void _recoverRangeDeletionsOnStepUp(OperationContext* opCtx);
diff --git a/src/mongo/db/s/range_deleter_service_test.cpp b/src/mongo/db/s/range_deleter_service_test.cpp
index 414f8b284d3..a6ba43ac540 100644
--- a/src/mongo/db/s/range_deleter_service_test.cpp
+++ b/src/mongo/db/s/range_deleter_service_test.cpp
@@ -536,6 +536,26 @@ TEST_F(RangeDeleterServiceTest, DumpState) {
         << "Expected " << state << " == " << expectedState;
 }
 
+TEST_F(RangeDeleterServiceTest, TotalNumOfRegisteredTasks) {
+    auto rds = RangeDeleterService::get(opCtx);
+    auto task0WithOngoingQueriesCollA = rangeDeletionTask0ForCollA;
+    auto task1WithOngoingQueriesCollA = rangeDeletionTask1ForCollA;
+    auto taskWithOngoingQueriesCollB = rangeDeletionTask0ForCollB;
+
+    // Register 2 tasks for `collA` and 1 task for `collB`
+    auto completionFuture0CollA =
+        rds->registerTask(rangeDeletionTask0ForCollA->getTask(),
+                          rangeDeletionTask0ForCollA->getOngoingQueriesFuture());
+    auto completionFuture1CollA =
+        rds->registerTask(rangeDeletionTask1ForCollA->getTask(),
+                          rangeDeletionTask1ForCollA->getOngoingQueriesFuture());
+    auto completionFutureCollB =
+        rds->registerTask(rangeDeletionTask0ForCollB->getTask(),
+                          rangeDeletionTask0ForCollB->getOngoingQueriesFuture());
+
+    ASSERT_EQ(3, rds->totalNumOfRegisteredTasks());
+}
+
 TEST_F(RangeDeleterServiceTest, RegisterTaskWithDisableResumableRangeDeleterFlagEnabled) {
 
     RAIIServerParameterControllerForTest enableFeatureFlag{"disableResumableRangeDeleter", true};