SERVER-35696 Provide a way to recover data files when lacking _mdb_catalog data, but have WiredTiger metadata

1 files changed, 20 insertions, 0 deletions

diff --git a/src/mongo/db/storage/kv/kv_storage_engine_test.cpp b/src/mongo/db/storage/kv/kv_storage_engine_test.cpp
index 997cf7826ff..f7e5655ebf8 100644
--- a/src/mongo/db/storage/kv/kv_storage_engine_test.cpp
+++ b/src/mongo/db/storage/kv/kv_storage_engine_test.cpp
@@ -304,5 +304,25 @@ TEST_F(KVStorageEngineRepairTest, ReconcileSucceeds) {
     ASSERT(collectionExists(opCtx.get(), collNs));
 }
 
+TEST_F(KVStorageEngineRepairTest, LoadCatalogRecoversOrphansInCatalog) {
+    auto opCtx = cc().makeOperationContext();
+
+    const NamespaceString collNs("db.coll1");
+    auto swIdentName = createCollection(opCtx.get(), collNs);
+    ASSERT_OK(swIdentName);
+    ASSERT(collectionExists(opCtx.get(), collNs));
+
+    AutoGetDb db(opCtx.get(), collNs.db(), LockMode::MODE_X);
+    ASSERT_OK(_storageEngine->getCatalog()->dropCollection(opCtx.get(), collNs.ns()));
+    ASSERT(!collectionExists(opCtx.get(), collNs));
+
+    // When in a repair context, loadCatalog recreates catalog entries for orphaned idents.
+    _storageEngine->loadCatalog(opCtx.get());
+    NamespaceString orphanNs = NamespaceString("local.system.orphan-" + swIdentName.getValue());
+
+    ASSERT(identExists(opCtx.get(), swIdentName.getValue()));
+    ASSERT(collectionExists(opCtx.get(), orphanNs));
+}
+
 }  // namespace
 }  // namespace mongo