1 files changed, 35 insertions, 1 deletions
diff --git a/src/mongo/db/index/index_access_method.cpp b/src/mongo/db/index/index_access_method.cpp
index 41ff27a6ddb..cde0fbaa055 100644
--- a/src/mongo/db/index/index_access_method.cpp
+++ b/src/mongo/db/index/index_access_method.cpp
@@ -41,6 +41,7 @@
 #include "mongo/db/catalog/index_catalog.h"
 #include "mongo/db/catalog/index_consistency.h"
 #include "mongo/db/client.h"
+#include "mongo/db/commands/server_status.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
 #include "mongo/db/curop.h"
 #include "mongo/db/index/index_access_method_gen.h"
@@ -52,6 +53,7 @@
 #include "mongo/db/repl/timestamp_block.h"
 #include "mongo/db/storage/durable_catalog.h"
 #include "mongo/db/storage/storage_options.h"
+#include "mongo/platform/atomic_word.h"
 #include "mongo/util/log.h"
 #include "mongo/util/progress_meter.h"
 #include "mongo/util/scopeguard.h"
@@ -72,6 +74,36 @@ static const RecordId kMultikeyMetadataKeyId =
     RecordId{RecordId::ReservedId::kWildcardMultikeyMetadataId};
 
 /**
+ * Metrics for index bulk builder operations. Intended to support index build diagnostics
+ * during the following scenarios:
+ * - createIndex commands;
+ * - collection cloning during initial sync; and
+ * - resuming index builds at startup.
+ *
+ * Also includes statistics for disk usage (by the external sorter) for index builds that
+ * do not fit in memory.
+ */
+class IndexBulkBuilderSSS : public ServerStatusSection {
+public:
+    IndexBulkBuilderSSS() : ServerStatusSection("indexBulkBuilder") {}
+
+    bool includeByDefault() const final {
+        return true;
+    }
+
+    void addRequiredPrivileges(std::vector<Privilege>* out) final {}
+
+    BSONObj generateSection(OperationContext* opCtx, const BSONElement& configElement) const final {
+        BSONObjBuilder builder;
+        builder.append("count", count.loadRelaxed());
+        return builder.obj();
+    }
+
+    // Number of instances of the bulk builder created.
+    AtomicWord<long long> count;
+} indexBulkBuilderSSS;
+
+/**
  * Returns true if at least one prefix of any of the indexed fields causes the index to be
  * multikey, and returns false otherwise. This function returns false if the 'multikeyPaths'
  * vector is empty.
@@ -600,7 +632,9 @@ AbstractIndexAccessMethod::BulkBuilderImpl::BulkBuilderImpl(const IndexAccessMet
               .ExtSortAllowed()
               .MaxMemoryUsageBytes(maxMemoryUsageBytes),
           BtreeExternalSortComparison(descriptor->keyPattern(), descriptor->version()))),
-      _real(index) {}
+      _real(index) {
+    indexBulkBuilderSSS.count.addAndFetch(1);
+}
 
 Status AbstractIndexAccessMethod::BulkBuilderImpl::insert(OperationContext* opCtx,
                                                           const BSONObj& obj,