SERVER-75733 Return StringData in NSS::ns, DatabaseName::db

133 files changed, 356 insertions, 295 deletions

diff --git a/src/mongo/client/dbclient_cursor.h b/src/mongo/client/dbclient_cursor.h
index c5cfd1484bb..9499e1ac51b 100644
--- a/src/mongo/client/dbclient_cursor.h
+++ b/src/mongo/client/dbclient_cursor.h
@@ -190,7 +190,7 @@ public:
         return _originalHost;
     }
 
-    std::string getns() const {
+    StringData getns() const {
         return _ns.ns();
     }
 
diff --git a/src/mongo/client/dbclient_rs.cpp b/src/mongo/client/dbclient_rs.cpp
index 3257ee82712..368b1534ccb 100644
--- a/src/mongo/client/dbclient_rs.cpp
+++ b/src/mongo/client/dbclient_rs.cpp
@@ -502,7 +502,7 @@ std::unique_ptr<DBClientCursor> DBClientReplicaSet::find(FindCommandRequest find
                                                          const ReadPreferenceSetting& readPref,
                                                          ExhaustMode exhaustMode) {
     invariant(findRequest.getNamespaceOrUUID().nss());
-    const std::string nss = findRequest.getNamespaceOrUUID().nss()->ns();
+    const std::string nss = findRequest.getNamespaceOrUUID().nss()->ns().toString();
     if (_isSecondaryQuery(nss, findRequest.toBSON(BSONObj{}), readPref)) {
         LOGV2_DEBUG(5951202,
                     3,
diff --git a/src/mongo/client/fetcher.cpp b/src/mongo/client/fetcher.cpp
index 868ffb90a97..078ba89210a 100644
--- a/src/mongo/client/fetcher.cpp
+++ b/src/mongo/client/fetcher.cpp
@@ -167,7 +167,7 @@ Status parseCursorResponse(const BSONObj& obj,
 
 Fetcher::Fetcher(executor::TaskExecutor* executor,
                  const HostAndPort& source,
-                 const std::string& dbname,
+                 StringData dbname,
                  const BSONObj& findCmdObj,
                  CallbackFn work,
                  const BSONObj& metadata,
diff --git a/src/mongo/client/fetcher.h b/src/mongo/client/fetcher.h
index 90ba61b00fc..b81fbc222ed 100644
--- a/src/mongo/client/fetcher.h
+++ b/src/mongo/client/fetcher.h
@@ -130,7 +130,7 @@ public:
      */
     Fetcher(executor::TaskExecutor* executor,
             const HostAndPort& source,
-            const std::string& dbname,
+            StringData dbname,
             const BSONObj& cmdObj,
             CallbackFn work,
             const BSONObj& metadata = ReadPreferenceSetting::secondaryPreferredMetadata(),
diff --git a/src/mongo/client/sasl_client_authenticate_impl.cpp b/src/mongo/client/sasl_client_authenticate_impl.cpp
index ffba7ba146d..1ceafc69d26 100644
--- a/src/mongo/client/sasl_client_authenticate_impl.cpp
+++ b/src/mongo/client/sasl_client_authenticate_impl.cpp
@@ -147,7 +147,7 @@ Status saslConfigureSession(SaslClientSession* session,
     status = bsonExtractStringField(saslParameters, saslCommandUserFieldName, &value);
     if (status.isOK()) {
         session->setParameter(SaslClientSession::parameterUser, value);
-    } else if ((targetDatabase != NamespaceString::kExternalDb) ||
+    } else if ((targetDatabase != DatabaseName::kExternal.db()) ||
                ((mechanism != auth::kMechanismMongoAWS) &&
                 (mechanism != auth::kMechanismMongoOIDC))) {
         return status;
@@ -164,7 +164,7 @@ Status saslConfigureSession(SaslClientSession* session,
     if (status.isOK()) {
         session->setParameter(SaslClientSession::parameterPassword, value);
     } else if (!(status == ErrorCodes::NoSuchKey &&
-                 targetDatabase == NamespaceString::kExternalDb)) {
+                 targetDatabase == DatabaseName::kExternal.db())) {
         // $external users do not have passwords, hence NoSuchKey is expected
         return status;
     }
diff --git a/src/mongo/db/auth/authorization_manager_impl.cpp b/src/mongo/db/auth/authorization_manager_impl.cpp
index 48d464814e6..aae5a36f297 100644
--- a/src/mongo/db/auth/authorization_manager_impl.cpp
+++ b/src/mongo/db/auth/authorization_manager_impl.cpp
@@ -411,7 +411,7 @@ StatusWith<UserHandle> AuthorizationManagerImpl::acquireUser(OperationContext* o
     // X.509 will give us our roles for initial acquire, but we have to lose them during
     // reacquire (for now) so reparse those roles into the request if not already present.
     if ((request.roles == boost::none) && request.mechanismData.empty() &&
-        (userName.getDB() == "$external"_sd)) {
+        (userName.getDB() == DatabaseName::kExternal.db())) {
         userRequest = getX509UserRequest(opCtx, std::move(userRequest));
     }
 #endif
@@ -530,7 +530,7 @@ Status AuthorizationManagerImpl::refreshExternalUsers(OperationContext* opCtx) {
     // First, get a snapshot of the UserHandles in the cache.
     auto cachedUsers =
         _userCache.peekLatestCachedIf([&](const UserRequest& userRequest, const User&) {
-            return userRequest.name.getDB() == "$external"_sd;
+            return userRequest.name.getDB() == DatabaseName::kExternal.db();
         });
 
     // Then, retrieve the corresponding Users from the backing store for users in the $external
diff --git a/src/mongo/db/auth/authorization_manager_test.cpp b/src/mongo/db/auth/authorization_manager_test.cpp
index 4a9f4db10ed..dcce21d5aea 100644
--- a/src/mongo/db/auth/authorization_manager_test.cpp
+++ b/src/mongo/db/auth/authorization_manager_test.cpp
@@ -349,7 +349,7 @@ TEST_F(AuthorizationManagerTest, testRefreshExternalV2User) {
 
     // Assert that all checked-out $external users are now marked invalid.
     for (const auto& checkedOutUser : checkedOutUsers) {
-        if (checkedOutUser->getName().getDB() == "$external"_sd) {
+        if (checkedOutUser->getName().getDB() == DatabaseName::kExternal.db()) {
             ASSERT(!checkedOutUser.isValid());
         } else {
             ASSERT(checkedOutUser.isValid());
@@ -368,7 +368,7 @@ TEST_F(AuthorizationManagerTest, testRefreshExternalV2User) {
         ASSERT(user.isValid());
 
         RoleNameIterator cachedUserRolesIt = user->getRoles();
-        if (userDoc.getStringField(kDbFieldName) == "$external"_sd) {
+        if (userDoc.getStringField(kDbFieldName) == DatabaseName::kExternal.db()) {
             for (const auto& userDocRole : updatedRoles) {
                 ASSERT_EQUALS(cachedUserRolesIt.next(),
                               RoleName(userDocRole.getStringField(kRoleFieldName),
diff --git a/src/mongo/db/auth/authorization_session_impl.cpp b/src/mongo/db/auth/authorization_session_impl.cpp
index 82fb7078846..8e6e49300ea 100644
--- a/src/mongo/db/auth/authorization_session_impl.cpp
+++ b/src/mongo/db/auth/authorization_session_impl.cpp
@@ -732,7 +732,8 @@ void AuthorizationSessionImpl::_refreshUserInfoAsNeeded(OperationContext* opCtx)
         // backing LDAP host, it should be cleared from _authenticatedUser. This
         // guarantees that no operations can be performed until the LDAP host comes back up.
         // TODO SERVER-72678 avoid this edge case hack when rearchitecting user acquisition.
-        if (name.getDB() == "$external"_sd && currentUser->getUserRequest().mechanismData.empty()) {
+        if (name.getDB() == DatabaseName::kExternal.db() &&
+            currentUser->getUserRequest().mechanismData.empty()) {
             clearUser();
             LOGV2(5914804,
                   "Removed external user from session cache of user information because of "
diff --git a/src/mongo/db/auth/builtin_roles.tpl.cpp b/src/mongo/db/auth/builtin_roles.tpl.cpp
index b698f34fce7..bf6445461ee 100644
--- a/src/mongo/db/auth/builtin_roles.tpl.cpp
+++ b/src/mongo/db/auth/builtin_roles.tpl.cpp
@@ -153,7 +153,7 @@ const stdx::unordered_set<RoleName> kAdminBuiltinRoles = {
 // Therefore, granting privileges on this database does not make sense.
 bool isValidDB(const DatabaseName& dbname) {
     return NamespaceString::validDBName(dbname, NamespaceString::DollarInDbNameBehavior::Allow) &&
-        (dbname.db() != NamespaceString::kExternalDb);
+        (dbname.db() != DatabaseName::kExternal.db());
 }
 
 }  // namespace
diff --git a/src/mongo/db/auth/sasl_mechanism_registry.h b/src/mongo/db/auth/sasl_mechanism_registry.h
index 2112ad06e7d..b99138b6bd3 100644
--- a/src/mongo/db/auth/sasl_mechanism_registry.h
+++ b/src/mongo/db/auth/sasl_mechanism_registry.h
@@ -405,7 +405,7 @@ private:
     using MechList = std::vector<std::unique_ptr<ServerFactoryBase>>;
 
     MechList& _getMapRef(StringData dbName) {
-        return _getMapRef(dbName != "$external"_sd);
+        return _getMapRef(dbName != DatabaseName::kExternal.db());
     }
 
     MechList& _getMapRef(bool internal) {
diff --git a/src/mongo/db/auth/sasl_mechanism_registry_test.cpp b/src/mongo/db/auth/sasl_mechanism_registry_test.cpp
index 11bdb673859..81d1e62c918 100644
--- a/src/mongo/db/auth/sasl_mechanism_registry_test.cpp
+++ b/src/mongo/db/auth/sasl_mechanism_registry_test.cpp
@@ -251,7 +251,7 @@ public:
     SASLServerMechanismRegistry registry;
 
     const UserName internalSajack = {"sajack"_sd, "test"_sd};
-    const UserName externalSajack = {"sajack"_sd, "$external"_sd};
+    const UserName externalSajack = {"sajack"_sd, DatabaseName::kExternal.db()};
 };
 
 TEST_F(MechanismRegistryTest, acquireInternalMechanism) {
diff --git a/src/mongo/db/auth/user_cache_invalidator_job.cpp b/src/mongo/db/auth/user_cache_invalidator_job.cpp
index fe8650325f5..d7c599f1fd9 100644
--- a/src/mongo/db/auth/user_cache_invalidator_job.cpp
+++ b/src/mongo/db/auth/user_cache_invalidator_job.cpp
@@ -197,7 +197,7 @@ void UserCacheInvalidator::run() {
                           "users in cache",
                           "error"_attr = refreshStatus);
             try {
-                _authzManager->invalidateUsersFromDB(opCtx.get(), "$external"_sd);
+                _authzManager->invalidateUsersFromDB(opCtx.get(), DatabaseName::kExternal);
             } catch (const DBException& e) {
                 LOGV2_WARNING(5914805,
                               "Error invalidating $external users from user cache",
diff --git a/src/mongo/db/bulk_write_shard_test.cpp b/src/mongo/db/bulk_write_shard_test.cpp
index 5cd470c43f2..77320fd28e9 100644
--- a/src/mongo/db/bulk_write_shard_test.cpp
+++ b/src/mongo/db/bulk_write_shard_test.cpp
@@ -117,7 +117,7 @@ void installDatabaseMetadata(OperationContext* opCtx,
                              const DatabaseVersion& dbVersion) {
     AutoGetDb autoDb(opCtx, dbName, MODE_X);
     auto scopedDss = DatabaseShardingState::assertDbLockedAndAcquireExclusive(opCtx, dbName);
-    scopedDss->setDbInfo(opCtx, {dbName.db(), ShardId("this"), dbVersion});
+    scopedDss->setDbInfo(opCtx, {dbName.db().toString(), ShardId("this"), dbVersion});
 }
 
 void installUnshardedCollectionMetadata(OperationContext* opCtx, const NamespaceString& nss) {
diff --git a/src/mongo/db/catalog/collection_catalog_test.cpp b/src/mongo/db/catalog/collection_catalog_test.cpp
index 124af7ceb36..2fdb7571359 100644
--- a/src/mongo/db/catalog/collection_catalog_test.cpp
+++ b/src/mongo/db/catalog/collection_catalog_test.cpp
@@ -396,7 +396,8 @@ TEST_F(CollectionCatalogTest, OnDropCollection) {
 
 TEST_F(CollectionCatalogTest, RenameCollection) {
     auto uuid = UUID::gen();
-    NamespaceString oldNss = NamespaceString::createNamespaceString_forTest(nss.db(), "oldcol");
+    NamespaceString oldNss =
+        NamespaceString::createNamespaceString_forTest(DatabaseName{nss.db()}, "oldcol");
     std::shared_ptr<Collection> collShared = std::make_shared<CollectionMock>(uuid, oldNss);
     auto collection = collShared.get();
     catalog.registerCollection(opCtx.get(), uuid, std::move(collShared), boost::none);
@@ -1110,7 +1111,7 @@ private:
     }
 
     void _dropCollection(OperationContext* opCtx, const NamespaceString& nss, Timestamp timestamp) {
-        Lock::DBLock dbLk(opCtx, nss.db(), MODE_IX);
+        Lock::DBLock dbLk(opCtx, DatabaseName{nss.db()}, MODE_IX);
         Lock::CollectionLock collLk(opCtx, nss, MODE_X);
         CollectionWriter collection(opCtx, nss);
 
@@ -1146,7 +1147,7 @@ private:
                            const NamespaceString& from,
                            const NamespaceString& to,
                            Timestamp timestamp) {
-        Lock::DBLock dbLk(opCtx, from.db(), MODE_IX);
+        Lock::DBLock dbLk(opCtx, DatabaseName{from.db()}, MODE_IX);
         Lock::CollectionLock fromLk(opCtx, from, MODE_X);
         Lock::CollectionLock toLk(opCtx, to, MODE_X);
 
@@ -2704,9 +2705,11 @@ TEST_F(CollectionCatalogTimestampTest, CatalogIdMappingInsert) {
         CollectionCatalog::get(opCtx.get())
             ->establishConsistentCollection(opCtx.get(), nss, Timestamp(1, 17));
         CollectionCatalog::get(opCtx.get())
-            ->establishConsistentCollection(opCtx.get(), {nss.db(), firstUUID}, Timestamp(1, 17));
+            ->establishConsistentCollection(
+                opCtx.get(), {DatabaseName{nss.db()}, firstUUID}, Timestamp(1, 17));
         CollectionCatalog::get(opCtx.get())
-            ->establishConsistentCollection(opCtx.get(), {nss.db(), secondUUID}, Timestamp(1, 17));
+            ->establishConsistentCollection(
+                opCtx.get(), {DatabaseName{nss.db()}, secondUUID}, Timestamp(1, 17));
 
         // Lookups before the inserted timestamp is still unknown
         ASSERT_EQ(lookupCatalogId(nss, firstUUID, Timestamp(1, 11)).result,
@@ -2737,9 +2740,11 @@ TEST_F(CollectionCatalogTimestampTest, CatalogIdMappingInsert) {
         CollectionCatalog::get(opCtx.get())
             ->establishConsistentCollection(opCtx.get(), nss, Timestamp(1, 12));
         CollectionCatalog::get(opCtx.get())
-            ->establishConsistentCollection(opCtx.get(), {nss.db(), firstUUID}, Timestamp(1, 12));
+            ->establishConsistentCollection(
+                opCtx.get(), {DatabaseName{nss.db()}, firstUUID}, Timestamp(1, 12));
         CollectionCatalog::get(opCtx.get())
-            ->establishConsistentCollection(opCtx.get(), {nss.db(), secondUUID}, Timestamp(1, 12));
+            ->establishConsistentCollection(
+                opCtx.get(), {DatabaseName{nss.db()}, secondUUID}, Timestamp(1, 12));
 
         // We should now have extended the range from Timestamp(1, 17) to Timestamp(1, 12)
         ASSERT_EQ(lookupCatalogId(nss, firstUUID, Timestamp(1, 12)).result,
@@ -2769,9 +2774,11 @@ TEST_F(CollectionCatalogTimestampTest, CatalogIdMappingInsert) {
         CollectionCatalog::get(opCtx.get())
             ->establishConsistentCollection(opCtx.get(), nss, Timestamp(1, 25));
         CollectionCatalog::get(opCtx.get())
-            ->establishConsistentCollection(opCtx.get(), {nss.db(), firstUUID}, Timestamp(1, 25));
+            ->establishConsistentCollection(
+                opCtx.get(), {DatabaseName{nss.db()}, firstUUID}, Timestamp(1, 25));
         CollectionCatalog::get(opCtx.get())
-            ->establishConsistentCollection(opCtx.get(), {nss.db(), secondUUID}, Timestamp(1, 25));
+            ->establishConsistentCollection(
+                opCtx.get(), {DatabaseName{nss.db()}, secondUUID}, Timestamp(1, 25));
 
         // Check the entries, most didn't change
         ASSERT_EQ(lookupCatalogId(nss, firstUUID, Timestamp(1, 17)).result,
@@ -2805,9 +2812,11 @@ TEST_F(CollectionCatalogTimestampTest, CatalogIdMappingInsert) {
         CollectionCatalog::get(opCtx.get())
             ->establishConsistentCollection(opCtx.get(), nss, Timestamp(1, 26));
         CollectionCatalog::get(opCtx.get())
-            ->establishConsistentCollection(opCtx.get(), {nss.db(), firstUUID}, Timestamp(1, 26));
+            ->establishConsistentCollection(
+                opCtx.get(), {DatabaseName{nss.db()}, firstUUID}, Timestamp(1, 26));
         CollectionCatalog::get(opCtx.get())
-            ->establishConsistentCollection(opCtx.get(), {nss.db(), secondUUID}, Timestamp(1, 26));
+            ->establishConsistentCollection(
+                opCtx.get(), {DatabaseName{nss.db()}, secondUUID}, Timestamp(1, 26));
 
         // We should not have re-written the existing entry at Timestamp(1, 26)
         ASSERT_EQ(lookupCatalogId(nss, firstUUID, Timestamp(1, 17)).result,
@@ -3934,7 +3943,7 @@ TEST_F(CollectionCatalogTimestampTest, ResolveNamespaceStringOrUUIDAtLatest) {
     const NamespaceString nss = NamespaceString::createNamespaceString_forTest("a.b");
     const Timestamp createCollectionTs = Timestamp(10, 10);
     const UUID uuid = createCollection(opCtx.get(), nss, createCollectionTs);
-    const NamespaceStringOrUUID nssOrUUID = NamespaceStringOrUUID(nss.db(), uuid);
+    const NamespaceStringOrUUID nssOrUUID = NamespaceStringOrUUID(DatabaseName{nss.db()}, uuid);
 
     NamespaceString resolvedNss =
         CollectionCatalog::get(opCtx.get())->resolveNamespaceStringOrUUID(opCtx.get(), nssOrUUID);
diff --git a/src/mongo/db/catalog/drop_database_test.cpp b/src/mongo/db/catalog/drop_database_test.cpp
index 9f9ea38f8f6..fd29c8b9f07 100644
--- a/src/mongo/db/catalog/drop_database_test.cpp
+++ b/src/mongo/db/catalog/drop_database_test.cpp
@@ -198,7 +198,7 @@ void _createCollection(OperationContext* opCtx, const NamespaceString& nss) {
  * Removes database from catalog, bypassing dropDatabase().
  */
 void _removeDatabaseFromCatalog(OperationContext* opCtx, StringData dbName) {
-    AutoGetDb autoDB(opCtx, dbName, MODE_X);
+    AutoGetDb autoDB(opCtx, DatabaseName{dbName}, MODE_X);
     auto db = autoDB.getDb();
     // dropDatabase can call awaitReplication more than once, so do not attempt to drop the database
     // twice.
diff --git a/src/mongo/db/catalog/rename_collection.cpp b/src/mongo/db/catalog/rename_collection.cpp
index e399d47b76a..21939a4a1d7 100644
--- a/src/mongo/db/catalog/rename_collection.cpp
+++ b/src/mongo/db/catalog/rename_collection.cpp
@@ -482,7 +482,7 @@ Status renameCollectionAcrossDatabases(OperationContext* opCtx,
         targetDBLock.emplace(opCtx, target.dbName(), MODE_X);
     }
 
-    DatabaseShardingState::assertMatchingDbVersion(opCtx, source.db());
+    DatabaseShardingState::assertMatchingDbVersion(opCtx, DatabaseName{source.db()});
 
     DisableDocumentValidation validationDisabler(opCtx);
 
diff --git a/src/mongo/db/catalog_raii.cpp b/src/mongo/db/catalog_raii.cpp
index 1773269fd77..704c5480de2 100644
--- a/src/mongo/db/catalog_raii.cpp
+++ b/src/mongo/db/catalog_raii.cpp
@@ -483,7 +483,7 @@ AutoGetCollectionLockFree::AutoGetCollectionLockFree(OperationContext* opCtx,
     // Check that the sharding database version matches our read.
     // Note: this must always be checked, regardless of whether the collection exists, so that the
     // dbVersion of this node or the caller gets updated quickly in case either is stale.
-    DatabaseShardingState::assertMatchingDbVersion(opCtx, _resolvedNss.db());
+    DatabaseShardingState::assertMatchingDbVersion(opCtx, DatabaseName{_resolvedNss.db()});
 
     checkCollectionUUIDMismatch(opCtx, _resolvedNss, _collectionPtr, options._expectedUUID);
 
diff --git a/src/mongo/db/catalog_raii_test.cpp b/src/mongo/db/catalog_raii_test.cpp
index 7ed2fc9f3b5..e273eb65639 100644
--- a/src/mongo/db/catalog_raii_test.cpp
+++ b/src/mongo/db/catalog_raii_test.cpp
@@ -240,8 +240,8 @@ TEST_F(CatalogRAIITestFixture, AutoGetCollectionSecondaryNamespacesSingleDb) {
     ASSERT(opCtx1->lockState()->isRSTLLocked());
     ASSERT(opCtx1->lockState()->isReadLocked());  // Global lock check
     ASSERT(opCtx1->lockState()->isDbLockedForMode(nss.dbName(), MODE_IS));
-    ASSERT(opCtx1->lockState()->isDbLockedForMode(kSecondaryNss1.db(), MODE_IS));
-    ASSERT(opCtx1->lockState()->isDbLockedForMode(kSecondaryNss2.db(), MODE_IS));
+    ASSERT(opCtx1->lockState()->isDbLockedForMode(DatabaseName{kSecondaryNss1.db()}, MODE_IS));
+    ASSERT(opCtx1->lockState()->isDbLockedForMode(DatabaseName{kSecondaryNss2.db()}, MODE_IS));
     ASSERT(opCtx1->lockState()->isCollectionLockedForMode(nss, MODE_IS));
     ASSERT(opCtx1->lockState()->isCollectionLockedForMode(kSecondaryNss1, MODE_IS));
     ASSERT(opCtx1->lockState()->isCollectionLockedForMode(kSecondaryNss2, MODE_IS));
@@ -249,8 +249,10 @@ TEST_F(CatalogRAIITestFixture, AutoGetCollectionSecondaryNamespacesSingleDb) {
     ASSERT(!opCtx1->lockState()->isRSTLExclusive());
     ASSERT(!opCtx1->lockState()->isGlobalLockedRecursively());
     ASSERT(!opCtx1->lockState()->isWriteLocked());
-    ASSERT(!opCtx1->lockState()->isDbLockedForMode(kSecondaryNssOtherDb1.db(), MODE_IS));
-    ASSERT(!opCtx1->lockState()->isDbLockedForMode(kSecondaryNssOtherDb2.db(), MODE_IS));
+    ASSERT(
+        !opCtx1->lockState()->isDbLockedForMode(DatabaseName{kSecondaryNssOtherDb1.db()}, MODE_IS));
+    ASSERT(
+        !opCtx1->lockState()->isDbLockedForMode(DatabaseName{kSecondaryNssOtherDb2.db()}, MODE_IS));
     ASSERT(!opCtx1->lockState()->isCollectionLockedForMode(kSecondaryNssOtherDb1, MODE_IS));
     ASSERT(!opCtx1->lockState()->isCollectionLockedForMode(kSecondaryNssOtherDb2, MODE_IS));
 
@@ -276,16 +278,18 @@ TEST_F(CatalogRAIITestFixture, AutoGetCollectionMultiNamespacesMODEIX) {
     ASSERT(opCtx1->lockState()->isRSTLLocked());
     ASSERT(opCtx1->lockState()->isWriteLocked());  // Global lock check
     ASSERT(opCtx1->lockState()->isDbLockedForMode(nss.dbName(), MODE_IX));
-    ASSERT(opCtx1->lockState()->isDbLockedForMode(kSecondaryNss1.db(), MODE_IX));
-    ASSERT(opCtx1->lockState()->isDbLockedForMode(kSecondaryNss2.db(), MODE_IX));
+    ASSERT(opCtx1->lockState()->isDbLockedForMode(DatabaseName{kSecondaryNss1.db()}, MODE_IX));
+    ASSERT(opCtx1->lockState()->isDbLockedForMode(DatabaseName{kSecondaryNss2.db()}, MODE_IX));
     ASSERT(opCtx1->lockState()->isCollectionLockedForMode(nss, MODE_IX));
     ASSERT(opCtx1->lockState()->isCollectionLockedForMode(kSecondaryNss1, MODE_IX));
     ASSERT(opCtx1->lockState()->isCollectionLockedForMode(kSecondaryNss2, MODE_IX));
 
     ASSERT(!opCtx1->lockState()->isRSTLExclusive());
     ASSERT(!opCtx1->lockState()->isGlobalLockedRecursively());
-    ASSERT(!opCtx1->lockState()->isDbLockedForMode(kSecondaryNssOtherDb1.db(), MODE_IX));
-    ASSERT(!opCtx1->lockState()->isDbLockedForMode(kSecondaryNssOtherDb2.db(), MODE_IX));
+    ASSERT(
+        !opCtx1->lockState()->isDbLockedForMode(DatabaseName{kSecondaryNssOtherDb1.db()}, MODE_IX));
+    ASSERT(
+        !opCtx1->lockState()->isDbLockedForMode(DatabaseName{kSecondaryNssOtherDb2.db()}, MODE_IX));
     ASSERT(!opCtx1->lockState()->isCollectionLockedForMode(kSecondaryNssOtherDb1, MODE_IX));
     ASSERT(!opCtx1->lockState()->isCollectionLockedForMode(kSecondaryNssOtherDb2, MODE_IX));
 
@@ -303,11 +307,11 @@ TEST_F(CatalogRAIITestFixture, AutoGetDbSecondaryNamespacesSingleDb) {
     ASSERT(opCtx1->lockState()->isRSTLLocked());
     ASSERT(opCtx1->lockState()->isReadLocked());  // Global lock check
     ASSERT(opCtx1->lockState()->isDbLockedForMode(nss.dbName(), MODE_IS));
-    ASSERT(opCtx1->lockState()->isDbLockedForMode(kSecondaryNss1.db(), MODE_IS));
-    ASSERT(opCtx1->lockState()->isDbLockedForMode(kSecondaryNss2.db(), MODE_IS));
+    ASSERT(opCtx1->lockState()->isDbLockedForMode(kSecondaryNss1.dbName(), MODE_IS));
+    ASSERT(opCtx1->lockState()->isDbLockedForMode(kSecondaryNss2.dbName(), MODE_IS));
 
-    ASSERT(!opCtx1->lockState()->isDbLockedForMode(kSecondaryNssOtherDb1.db(), MODE_IS));
-    ASSERT(!opCtx1->lockState()->isDbLockedForMode(kSecondaryNssOtherDb2.db(), MODE_IS));
+    ASSERT(!opCtx1->lockState()->isDbLockedForMode(kSecondaryNssOtherDb1.dbName(), MODE_IS));
+    ASSERT(!opCtx1->lockState()->isDbLockedForMode(kSecondaryNssOtherDb2.dbName(), MODE_IS));
     ASSERT(!opCtx1->lockState()->isRSTLExclusive());
     ASSERT(!opCtx1->lockState()->isGlobalLockedRecursively());
     ASSERT(!opCtx1->lockState()->isWriteLocked());
@@ -321,7 +325,8 @@ TEST_F(CatalogRAIITestFixture, AutoGetCollectionMultiNssCollLockDeadline) {
     // Take a MODE_X collection lock on kSecondaryNss1.
     boost::optional<AutoGetCollection> autoGetCollWithXLock;
     autoGetCollWithXLock.emplace(client1.second.get(), kSecondaryNss1, MODE_X);
-    ASSERT(client1.second->lockState()->isDbLockedForMode(kSecondaryNss1.db(), MODE_IX));
+    ASSERT(
+        client1.second->lockState()->isDbLockedForMode(DatabaseName{kSecondaryNss1.db()}, MODE_IX));
     ASSERT(client1.second->lockState()->isCollectionLockedForMode(kSecondaryNss1, MODE_X));
 
     // Now trying to take a MODE_IS lock on kSecondaryNss1 as a secondary collection should fail.
diff --git a/src/mongo/db/cloner.cpp b/src/mongo/db/cloner.cpp
index 682208b774e..1f9f7f0f255 100644
--- a/src/mongo/db/cloner.cpp
+++ b/src/mongo/db/cloner.cpp
@@ -597,7 +597,7 @@ Status Cloner::copyDb(OperationContext* opCtx,
 
         const NamespaceString nss(dBName, params.collectionName);
 
-        clonedColls->insert(nss.ns());
+        clonedColls->insert(nss.ns().toString());
 
         LOGV2_DEBUG(20421, 1, "\t\t cloning", logAttrs(nss), "host"_attr = masterHost);
 
diff --git a/src/mongo/db/commands.cpp b/src/mongo/db/commands.cpp
index 868c37da94f..1cc63cf1336 100644
--- a/src/mongo/db/commands.cpp
+++ b/src/mongo/db/commands.cpp
@@ -280,7 +280,7 @@ std::string CommandHelpers::parseNsFullyQualified(const BSONObj& cmdObj) {
     uassert(ErrorCodes::InvalidNamespace,
             str::stream() << "Invalid namespace specified '" << nss.ns() << "'",
             nss.isValid());
-    return nss.ns();
+    return nss.ns().toString();
 }
 
 NamespaceString CommandHelpers::parseNsCollectionRequired(const DatabaseName& dbName,
@@ -321,7 +321,7 @@ NamespaceStringOrUUID CommandHelpers::parseNsOrUUID(const DatabaseName& dbName,
 }
 
 std::string CommandHelpers::parseNsFromCommand(StringData dbname, const BSONObj& cmdObj) {
-    return parseNsFromCommand({boost::none, dbname}, cmdObj).ns();
+    return parseNsFromCommand({boost::none, dbname}, cmdObj).ns().toString();
 }
 
 NamespaceString CommandHelpers::parseNsFromCommand(const DatabaseName& dbName,
@@ -333,7 +333,7 @@ NamespaceString CommandHelpers::parseNsFromCommand(const DatabaseName& dbName,
                                                           cmdObj.firstElement().valueStringData());
 }
 
-ResourcePattern CommandHelpers::resourcePatternForNamespace(const std::string& ns) {
+ResourcePattern CommandHelpers::resourcePatternForNamespace(StringData ns) {
     if (!NamespaceString::validCollectionComponent(ns)) {
         return ResourcePattern::forDatabaseName(ns);
     }
diff --git a/src/mongo/db/commands.h b/src/mongo/db/commands.h
index d06b9a12805..e88f43b8d2b 100644
--- a/src/mongo/db/commands.h
+++ b/src/mongo/db/commands.h
@@ -165,7 +165,7 @@ struct CommandHelpers {
      * pattern or a database resource pattern, depending on whether parseNs returns a fully qualifed
      * collection name or just a database name.
      */
-    static ResourcePattern resourcePatternForNamespace(const std::string& ns);
+    static ResourcePattern resourcePatternForNamespace(StringData ns);
 
     static Command* findCommand(StringData name);
 
diff --git a/src/mongo/db/commands/authentication_commands.cpp b/src/mongo/db/commands/authentication_commands.cpp
index 97419827dde..f1c02c967a1 100644
--- a/src/mongo/db/commands/authentication_commands.cpp
+++ b/src/mongo/db/commands/authentication_commands.cpp
@@ -59,7 +59,6 @@
 namespace mongo {
 namespace {
 
-constexpr auto kExternalDB = "$external"_sd;
 constexpr auto kDBFieldName = "db"_sd;
 
 /**
@@ -122,7 +121,7 @@ public:
 
             as->logoutDatabase(
                 opCtx->getClient(), dbname.toStringWithTenantId(), "Logging out on user request");
-            if (getTestCommandsEnabled() && (dbname == kAdminDB)) {
+            if (getTestCommandsEnabled() && (dbname.db() == kAdminDB)) {
                 // Allows logging out as the internal user against the admin database, however
                 // this actually logs out of the local database as well. This is to
                 // support the auth passthrough test framework on mongos (since you can't use the
@@ -213,7 +212,7 @@ void _authenticateX509(OperationContext* opCtx, AuthenticationSession* session)
 
     uassert(ErrorCodes::ProtocolError,
             "X.509 authentication must always use the $external database.",
-            userName.getDB() == kExternalDB);
+            userName.getDB() == DatabaseName::kExternal.db());
 
     auto isInternalClient = [&]() -> bool {
         return opCtx->getClient()->session()->getTags() & transport::Session::kInternalClient;
@@ -396,7 +395,7 @@ void doSpeculativeAuthenticate(OperationContext* opCtx,
 
     if (!hasDBField) {
         // No "db" field was provided, so default to "$external"
-        cmd.append(AuthenticateCommand::kDbNameFieldName, kExternalDB);
+        cmd.append(AuthenticateCommand::kDbNameFieldName, DatabaseName::kExternal.db());
     }
 
     auto authCmdObj =
diff --git a/src/mongo/db/commands/dbcheck.cpp b/src/mongo/db/commands/dbcheck.cpp
index 5e1e700c894..94962d9f9a8 100644
--- a/src/mongo/db/commands/dbcheck.cpp
+++ b/src/mongo/db/commands/dbcheck.cpp
@@ -543,7 +543,7 @@ private:
 
             collection = catalog->establishConsistentCollection(
                 opCtx,
-                {info.nss.db(), info.uuid},
+                {DatabaseName{info.nss.db()}, info.uuid},
                 opCtx->recoveryUnit()->getPointInTimeReadTimestamp(opCtx));
         } else {
             autoColl.emplace(opCtx, info.nss, MODE_IS);
diff --git a/src/mongo/db/commands/internal_rename_if_options_and_indexes_match_cmd.cpp b/src/mongo/db/commands/internal_rename_if_options_and_indexes_match_cmd.cpp
index 4a12c44304f..c171aae513b 100644
--- a/src/mongo/db/commands/internal_rename_if_options_and_indexes_match_cmd.cpp
+++ b/src/mongo/db/commands/internal_rename_if_options_and_indexes_match_cmd.cpp
@@ -78,7 +78,7 @@ public:
             }
 
             // Check if the receiving shard is still the primary for the database
-            DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, fromNss.db());
+            DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, DatabaseName{fromNss.db()});
 
             // Acquiring the local part of the distributed locks for involved namespaces allows:
             // - Serialize with sharded DDLs, ensuring no concurrent modifications of the
diff --git a/src/mongo/db/commands/list_databases_common.h b/src/mongo/db/commands/list_databases_common.h
index 2143131f882..942f1e76aff 100644
--- a/src/mongo/db/commands/list_databases_common.h
+++ b/src/mongo/db/commands/list_databases_common.h
@@ -99,7 +99,8 @@ int64_t setReplyItems(OperationContext* opCtx,
         }
 
         // If setTenantId is true, always return the dbName without the tenantId
-        ReplyItemType item(setTenantId ? dbName.db() : DatabaseNameUtil::serialize(dbName));
+        ReplyItemType item(setTenantId ? dbName.db().toString()
+                                       : DatabaseNameUtil::serialize(dbName));
         if (setTenantId) {
             initializeItemWithTenantId(item, dbName);
         }
diff --git a/src/mongo/db/commands/mr_common.cpp b/src/mongo/db/commands/mr_common.cpp
index 51d7e7191d4..0806741d992 100644
--- a/src/mongo/db/commands/mr_common.cpp
+++ b/src/mongo/db/commands/mr_common.cpp
@@ -269,7 +269,7 @@ auto translateOut(boost::intrusive_ptr<ExpressionContext> expCtx,
 
 }  // namespace
 
-OutputOptions parseOutputOptions(const std::string& dbname, const BSONObj& cmdObj) {
+OutputOptions parseOutputOptions(StringData dbname, const BSONObj& cmdObj) {
     OutputOptions outputOptions;
 
     outputOptions.outNonAtomic = true;
diff --git a/src/mongo/db/commands/mr_common.h b/src/mongo/db/commands/mr_common.h
index 965553e9ca8..0cb693453bb 100644
--- a/src/mongo/db/commands/mr_common.h
+++ b/src/mongo/db/commands/mr_common.h
@@ -49,7 +49,7 @@ struct OutputOptions {
     OutputType outType;
 };
 
-OutputOptions parseOutputOptions(const std::string& dbname, const BSONObj& cmdObj);
+OutputOptions parseOutputOptions(StringData dbname, const BSONObj& cmdObj);
 
 Status checkAuthForMapReduce(const BasicCommand* command,
                              OperationContext* opCtx,
diff --git a/src/mongo/db/commands/mr_test.cpp b/src/mongo/db/commands/mr_test.cpp
index 38cc3f73f81..6813016e3f7 100644
--- a/src/mongo/db/commands/mr_test.cpp
+++ b/src/mongo/db/commands/mr_test.cpp
@@ -112,7 +112,7 @@ void _testConfigParseOutputOptions(const std::string& dbname,
     _compareOutputOptionField(dbname,
                               cmdObjStr,
                               "finalNamespace",
-                              outputOptions.finalNamespace.ns(),
+                              outputOptions.finalNamespace.ns().toString(),
                               expectedFinalNamespace);
     _compareOutputOptionField(
         dbname, cmdObjStr, "outNonAtomic", outputOptions.outNonAtomic, expectedOutNonAtomic);
diff --git a/src/mongo/db/commands/plan_cache_clear_command.cpp b/src/mongo/db/commands/plan_cache_clear_command.cpp
index 7fa1bd499a2..b95ee31751c 100644
--- a/src/mongo/db/commands/plan_cache_clear_command.cpp
+++ b/src/mongo/db/commands/plan_cache_clear_command.cpp
@@ -67,7 +67,7 @@ PlanCache* getPlanCache(OperationContext* opCtx, const CollectionPtr& collection
 Status clear(OperationContext* opCtx,
              const CollectionPtr& collection,
              PlanCache* planCache,
-             const std::string& ns,
+             StringData ns,
              const BSONObj& cmdObj) {
     invariant(planCache);
 
diff --git a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
index f29ead477f5..645fd108bdb 100644
--- a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
+++ b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
@@ -163,7 +163,7 @@ void abortAllReshardCollection(OperationContext* opCtx) {
 
     std::vector<std::string> nsWithReshardColl;
     store.forEach(opCtx, {}, [&](const ReshardingCoordinatorDocument& doc) {
-        nsWithReshardColl.push_back(doc.getSourceNss().ns());
+        nsWithReshardColl.push_back(doc.getSourceNss().ns().toString());
         return true;
     });
 
@@ -843,7 +843,7 @@ private:
             ConfigsvrSetClusterParameter configsvrSetClusterParameter(
                 BSON("shardedClusterCardinalityForDirectConns"
                      << BSON("hasTwoOrMoreShards" << expectedValue)));
-            configsvrSetClusterParameter.setDbName(DatabaseName(boost::none, "admin"));
+            configsvrSetClusterParameter.setDbName(DatabaseName::kAdmin);
 
             const auto shardRegistry = Grid::get(opCtx)->shardRegistry();
             const auto cmdResponse =
diff --git a/src/mongo/db/commands/user_management_commands.cpp b/src/mongo/db/commands/user_management_commands.cpp
index a3c9fdb8bb3..e6b6a3cdae0 100644
--- a/src/mongo/db/commands/user_management_commands.cpp
+++ b/src/mongo/db/commands/user_management_commands.cpp
@@ -1013,7 +1013,7 @@ void CmdUMCTyped<CreateUserCommand>::Invocation::typedRun(OperationContext* opCt
             cmd.getCommandParameter().find('\0') == std::string::npos);
     UserName userName(cmd.getCommandParameter(), dbname);
 
-    const bool isExternal = dbname.db() == NamespaceString::kExternalDb;
+    const bool isExternal = dbname.db() == DatabaseName::kExternal.db();
     uassert(ErrorCodes::BadValue,
             "Must provide a 'pwd' field for all user documents, except those"
             " with '$external' as the user's source db",
@@ -1505,7 +1505,7 @@ void CmdUMCTyped<CreateRoleCommand>::Invocation::typedRun(OperationContext* opCt
 
     uassert(ErrorCodes::BadValue,
             "Cannot create roles in the $external database",
-            dbname.db() != NamespaceString::kExternalDb);
+            dbname.db() != DatabaseName::kExternal.db());
 
     uassert(ErrorCodes::BadValue,
             "Cannot create roles with the same name as a built-in role",
diff --git a/src/mongo/db/commands/validate_db_metadata_cmd.cpp b/src/mongo/db/commands/validate_db_metadata_cmd.cpp
index ea4a72feb8d..db2f3fa66ef 100644
--- a/src/mongo/db/commands/validate_db_metadata_cmd.cpp
+++ b/src/mongo/db/commands/validate_db_metadata_cmd.cpp
@@ -167,7 +167,7 @@ public:
         bool _validateView(OperationContext* opCtx, const ViewDefinition& view) {
             auto pipelineStatus = view_catalog_helpers::validatePipeline(opCtx, view);
             if (!pipelineStatus.isOK()) {
-                ErrorReplyElement error(view.name().ns(),
+                ErrorReplyElement error(view.name().ns().toString(),
                                         ErrorCodes::APIStrictError,
                                         ErrorCodes::errorString(ErrorCodes::APIStrictError),
                                         pipelineStatus.getStatus().reason());
@@ -204,7 +204,7 @@ public:
             }
             const auto status = collection->checkValidatorAPIVersionCompatability(opCtx);
             if (!status.isOK()) {
-                ErrorReplyElement error(coll.nss()->ns(),
+                ErrorReplyElement error(coll.nss()->ns().toString(),
                                         ErrorCodes::APIStrictError,
                                         ErrorCodes::errorString(ErrorCodes::APIStrictError),
                                         status.reason());
@@ -227,7 +227,7 @@ public:
                 const IndexDescriptor* desc = ii->next()->descriptor();
                 if (apiStrict && apiVersion == "1" &&
                     !index_key_validate::isIndexAllowedInAPIVersion1(*desc)) {
-                    ErrorReplyElement error(coll.nss()->ns(),
+                    ErrorReplyElement error(coll.nss()->ns().toString(),
                                             ErrorCodes::APIStrictError,
                                             ErrorCodes::errorString(ErrorCodes::APIStrictError),
                                             str::stream()
diff --git a/src/mongo/db/concurrency/lock_manager_defs.h b/src/mongo/db/concurrency/lock_manager_defs.h
index 6fbf8968552..23376734fe2 100644
--- a/src/mongo/db/concurrency/lock_manager_defs.h
+++ b/src/mongo/db/concurrency/lock_manager_defs.h
@@ -246,8 +246,7 @@ public:
         : _fullHash(fullHash(type, hashStringData(dbName.toStringWithTenantId()))) {
         verifyNoResourceMutex(type);
     }
-    ResourceId(ResourceType type, const std::string& str)
-        : _fullHash(fullHash(type, hashStringData(str))) {
+    ResourceId(ResourceType type, StringData str) : _fullHash(fullHash(type, hashStringData(str))) {
         // Resources of type database, collection, or tenant must never be passed as a raw string.
         invariant(type != RESOURCE_DATABASE && type != RESOURCE_COLLECTION &&
                   type != RESOURCE_TENANT);
diff --git a/src/mongo/db/curop.h b/src/mongo/db/curop.h
index 1c480498d7c..c915ffb2fcd 100644
--- a/src/mongo/db/curop.h
+++ b/src/mongo/db/curop.h
@@ -577,7 +577,9 @@ public:
         if (_dbprofile <= 0)
             return false;
 
-        if (CollectionCatalog::get(opCtx())->getDatabaseProfileSettings(getNSS().db()).filter)
+        if (CollectionCatalog::get(opCtx())
+                ->getDatabaseProfileSettings(DatabaseName{getNSS().db()})
+                .filter)
             return true;
 
         return elapsedTimeExcludingPauses() >= Milliseconds{serverGlobalParams.slowMS.load()};
diff --git a/src/mongo/db/database_name.h b/src/mongo/db/database_name.h
index f68876bd030..63649f5c50d 100644
--- a/src/mongo/db/database_name.h
+++ b/src/mongo/db/database_name.h
@@ -131,19 +131,19 @@ public:
      * Prefer to use the constructor above.
      * TODO SERVER-65456 Remove this constructor.
      */
-    DatabaseName(StringData dbName, boost::optional<TenantId> tenantId = boost::none)
+    explicit DatabaseName(StringData dbName, boost::optional<TenantId> tenantId = boost::none)
         : DatabaseName(std::move(tenantId), dbName) {}
 
     const boost::optional<TenantId>& tenantId() const {
         return _tenantId;
     }
 
-    const std::string& db() const {
+    StringData db() const {
         return _dbString;
     }
 
-    const std::string& toString() const {
-        return db();
+    std::string toString() const {
+        return db().toString();
     }
 
     std::string toStringWithTenantId() const {
diff --git a/src/mongo/db/database_name_reserved.def.h b/src/mongo/db/database_name_reserved.def.h
index 062fdd4317e..38b0cf17684 100644
--- a/src/mongo/db/database_name_reserved.def.h
+++ b/src/mongo/db/database_name_reserved.def.h
@@ -46,4 +46,6 @@ DBNAME_CONSTANT(kConfig, "config"_sd)
 
 DBNAME_CONSTANT(kSystem, "system"_sd)
 
+DBNAME_CONSTANT(kExternal, "$external"_sd)
+
 DBNAME_CONSTANT(kEmpty, ""_sd)
diff --git a/src/mongo/db/db_raii.cpp b/src/mongo/db/db_raii.cpp
index 64b9dbe68a0..3e9dde0821b 100644
--- a/src/mongo/db/db_raii.cpp
+++ b/src/mongo/db/db_raii.cpp
@@ -1304,7 +1304,7 @@ AutoGetCollectionForReadLockFreePITCatalog::AutoGetCollectionForReadLockFreePITC
     invariant(supportsLockFreeRead(opCtx) &&
               (!opCtx->recoveryUnit()->isActive() || _isLockFreeReadSubOperation));
 
-    DatabaseShardingState::assertMatchingDbVersion(opCtx, nsOrUUID.db());
+    DatabaseShardingState::assertMatchingDbVersion(opCtx, DatabaseName{nsOrUUID.db()});
 
     auto readConcernArgs = repl::ReadConcernArgs::get(opCtx);
     if (_isLockFreeReadSubOperation) {
diff --git a/src/mongo/db/fle_crud.cpp b/src/mongo/db/fle_crud.cpp
index 2cf9e1a5b6f..ed7e1be568c 100644
--- a/src/mongo/db/fle_crud.cpp
+++ b/src/mongo/db/fle_crud.cpp
@@ -1507,7 +1507,7 @@ std::vector<std::vector<FLEEdgeCountInfo>> FLEQueryInterfaceImpl::getTags(
     getCountsCmd.setTokens(toTagSets(tokensSets));
     getCountsCmd.setQueryType(queryTypeTranslation(type));
 
-    auto response = _txnClient.runCommandSync(nss.db(), getCountsCmd.toBSON({}));
+    auto response = _txnClient.runCommandSync(DatabaseName{nss.db()}, getCountsCmd.toBSON({}));
 
     auto status = getStatusFromWriteCommandReply(response);
     uassertStatusOK(status);
diff --git a/src/mongo/db/namespace_string.h b/src/mongo/db/namespace_string.h
index e53a46b5e12..6c59a451422 100644
--- a/src/mongo/db/namespace_string.h
+++ b/src/mongo/db/namespace_string.h
@@ -139,9 +139,6 @@ public:
 
     // Reserved system namespaces
 
-    // The $external database used by X.509, LDAP, etc...
-    static constexpr StringData kExternalDb = "$external"_sd;
-
     // Name for the system views collection
     static constexpr StringData kSystemDotViewsCollectionName = "system.views"_sd;
 
@@ -416,19 +413,20 @@ public:
             : StringData(_ns.c_str() + _dotIndex + 1, _ns.size() - 1 - _dotIndex);
     }
 
-    const std::string& ns() const {
-        return _ns;
+    StringData ns() const {
+        return StringData{_ns};
     }
 
-    const std::string& toString() const {
-        return ns();
+    std::string toString() const {
+        return ns().toString();
     }
 
     std::string toStringWithTenantId() const {
-        if (auto tenantId = _dbName.tenantId())
+        if (auto tenantId = _dbName.tenantId()) {
             return str::stream() << *tenantId << '_' << ns();
+        }
 
-        return ns();
+        return ns().toString();
     }
 
     /**
@@ -443,10 +441,11 @@ public:
      * It is called anytime a NamespaceString is logged by logAttrs or otherwise.
      */
     friend std::string toStringForLogging(const NamespaceString& nss) {
-        if (auto tenantId = nss.tenantId())
-            return str::stream() << *tenantId << '_' << nss.ns();
+        if (auto tenantId = nss.tenantId()) {
+            return str::stream() << *tenantId << '_' << nss.ns().toString();
+        }
 
-        return nss.ns();
+        return nss.ns().toString();
     }
 
     size_t size() const {
@@ -848,7 +847,7 @@ private:
 
 
     std::tuple<const boost::optional<TenantId>&, const std::string&> _lens() const {
-        return std::tie(tenantId(), ns());
+        return std::tie(tenantId(), _ns);
     }
 
     DatabaseName _dbName;
@@ -894,7 +893,7 @@ public:
      * TODO SERVER-66887 remove this function for better clarity once call sites have been changed
      */
     std::string dbname() const {
-        return _dbname ? _dbname->db() : "";
+        return _dbname ? _dbname->db().toString() : "";
     }
 
     const boost::optional<DatabaseName>& dbName() const {
diff --git a/src/mongo/db/op_observer/op_observer_impl_test.cpp b/src/mongo/db/op_observer/op_observer_impl_test.cpp
index f9d12984f34..920c4dc198a 100644
--- a/src/mongo/db/op_observer/op_observer_impl_test.cpp
+++ b/src/mongo/db/op_observer/op_observer_impl_test.cpp
@@ -641,7 +641,7 @@ TEST_F(OpObserverTest, OnDropCollectionInlcudesTenantId) {
 
     // Write to the oplog.
     {
-        AutoGetDb autoDb(opCtx.get(), nss.db(), MODE_X);
+        AutoGetDb autoDb(opCtx.get(), DatabaseName{nss.db()}, MODE_X);
         WriteUnitOfWork wunit(opCtx.get());
         opObserver.onDropCollection(
             opCtx.get(), nss, uuid, 0U, OpObserver::CollectionDropType::kTwoPhase);
@@ -705,7 +705,7 @@ TEST_F(OpObserverTest, OnRenameCollectionIncludesTenantIdFeatureFlagOff) {
 
     // Write to the oplog.
     {
-        AutoGetDb autoDb(opCtx.get(), sourceNss.db(), MODE_X);
+        AutoGetDb autoDb(opCtx.get(), DatabaseName{sourceNss.db()}, MODE_X);
         WriteUnitOfWork wunit(opCtx.get());
         opObserver.onRenameCollection(
             opCtx.get(), sourceNss, targetNss, uuid, dropTargetUuid, 0U, stayTemp);
@@ -741,7 +741,7 @@ TEST_F(OpObserverTest, OnRenameCollectionIncludesTenantIdFeatureFlagOn) {
 
     // Write to the oplog.
     {
-        AutoGetDb autoDb(opCtx.get(), sourceNss.db(), MODE_X);
+        AutoGetDb autoDb(opCtx.get(), DatabaseName{sourceNss.db()}, MODE_X);
         WriteUnitOfWork wunit(opCtx.get());
         opObserver.onRenameCollection(
             opCtx.get(), sourceNss, targetNss, uuid, dropTargetUuid, 0U, stayTemp);
@@ -866,7 +866,7 @@ TEST_F(OpObserverTest, ImportCollectionOplogEntryIncludesTenantId) {
 
     // Write to the oplog.
     {
-        AutoGetDb autoDb(opCtx.get(), nss.db(), MODE_X);
+        AutoGetDb autoDb(opCtx.get(), DatabaseName{nss.db()}, MODE_X);
         WriteUnitOfWork wunit(opCtx.get());
         opObserver.onImportCollection(opCtx.get(),
                                       importUUID,
diff --git a/src/mongo/db/pipeline/process_interface/shardsvr_process_interface.cpp b/src/mongo/db/pipeline/process_interface/shardsvr_process_interface.cpp
index d177df795cf..7ebc88e64f8 100644
--- a/src/mongo/db/pipeline/process_interface/shardsvr_process_interface.cpp
+++ b/src/mongo/db/pipeline/process_interface/shardsvr_process_interface.cpp
@@ -435,7 +435,7 @@ ShardServerProcessInterface::expectUnshardedCollectionInScope(
 
 void ShardServerProcessInterface::checkOnPrimaryShardForDb(OperationContext* opCtx,
                                                            const NamespaceString& nss) {
-    DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, nss.db());
+    DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, DatabaseName{nss.db()});
 }
 
 }  // namespace mongo
diff --git a/src/mongo/db/query/canonical_query.h b/src/mongo/db/query/canonical_query.h
index 17e837e9321..5375ec42ef0 100644
--- a/src/mongo/db/query/canonical_query.h
+++ b/src/mongo/db/query/canonical_query.h
@@ -120,11 +120,11 @@ public:
      */
     static Status isValidNormalized(const MatchExpression* root);
 
-    NamespaceString nss() const {
+    const NamespaceString& nss() const {
         invariant(_findCommand->getNamespaceOrUUID().nss());
         return *_findCommand->getNamespaceOrUUID().nss();
     }
-    std::string ns() const {
+    StringData ns() const {
         return nss().ns();
     }
 
diff --git a/src/mongo/db/query/planner_access.cpp b/src/mongo/db/query/planner_access.cpp
index ce5ecda4874..90dcca12860 100644
--- a/src/mongo/db/query/planner_access.cpp
+++ b/src/mongo/db/query/planner_access.cpp
@@ -429,7 +429,7 @@ std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::makeCollectionScan(
     const CanonicalQuery& query, bool tailable, const QueryPlannerParams& params, int direction) {
     // Make the (only) node, a collection scan.
     auto csn = std::make_unique<CollectionScanNode>();
-    csn->name = query.ns();
+    csn->name = query.ns().toString();
     csn->filter = query.root()->clone();
     csn->tailable = tailable;
     csn->shouldTrackLatestOplogTimestamp =
diff --git a/src/mongo/db/repl/cloner_test_fixture.cpp b/src/mongo/db/repl/cloner_test_fixture.cpp
index 0cdbd27b18a..448e5d68e00 100644
--- a/src/mongo/db/repl/cloner_test_fixture.cpp
+++ b/src/mongo/db/repl/cloner_test_fixture.cpp
@@ -49,9 +49,10 @@ BSONObj ClonerTestFixture::createCountResponse(int documentCount) {
 }
 
 /* static */
-BSONObj ClonerTestFixture::createCursorResponse(const std::string& nss, const BSONArray& docs) {
-    return BSON("cursor" << BSON("id" << CursorId(0) << "ns" << nss << "firstBatch" << docs) << "ok"
-                         << 1);
+BSONObj ClonerTestFixture::createCursorResponse(StringData nss, const BSONArray& docs) {
+    return BSON(
+        "cursor" << BSON("id" << CursorId(0) << "ns" << nss.toString() << "firstBatch" << docs)
+                 << "ok" << 1);
 }
 
 void ClonerTestFixture::setUp() {
diff --git a/src/mongo/db/repl/cloner_test_fixture.h b/src/mongo/db/repl/cloner_test_fixture.h
index 35d36d58250..e5d7d2f17a6 100644
--- a/src/mongo/db/repl/cloner_test_fixture.h
+++ b/src/mongo/db/repl/cloner_test_fixture.h
@@ -53,7 +53,7 @@ public:
 
     // Since the DBClient handles the cursor iterating, we assume that works for the purposes of the
     // cloner unit test and just use a single batch for all mock responses.
-    static BSONObj createCursorResponse(const std::string& nss, const BSONArray& docs);
+    static BSONObj createCursorResponse(StringData nss, const BSONArray& docs);
 
 protected:
     void setUp() override;
diff --git a/src/mongo/db/repl/initial_syncer_test.cpp b/src/mongo/db/repl/initial_syncer_test.cpp
index df015013477..5b5737f2f2d 100644
--- a/src/mongo/db/repl/initial_syncer_test.cpp
+++ b/src/mongo/db/repl/initial_syncer_test.cpp
@@ -330,7 +330,7 @@ protected:
         _storageInterface->dropCollFn = [this](OperationContext* opCtx,
                                                const NamespaceString& nss) {
             LockGuard lock(_storageInterfaceWorkDoneMutex);
-            _storageInterfaceWorkDone.droppedCollections.push_back(nss.ns());
+            _storageInterfaceWorkDone.droppedCollections.push_back(nss.ns().toString());
             return Status::OK();
         };
         _storageInterface->dropUserDBsFn = [this](OperationContext* opCtx) {
diff --git a/src/mongo/db/repl/oplog_applier_test.cpp b/src/mongo/db/repl/oplog_applier_test.cpp
index e0e21698f83..a5d4b10aecc 100644
--- a/src/mongo/db/repl/oplog_applier_test.cpp
+++ b/src/mongo/db/repl/oplog_applier_test.cpp
@@ -141,7 +141,8 @@ TEST_F(OplogApplierTest, GetNextApplierBatchGroupsUnpreparedApplyOpsOpWithOtherO
 
 TEST_F(OplogApplierTest, GetNextApplierBatchReturnsSystemDotViewsOpInOwnBatch) {
     std::vector<OplogEntry> srcOps;
-    srcOps.push_back(makeInsertOplogEntry(1, NamespaceString::makeSystemDotViewsNamespace(dbName)));
+    srcOps.push_back(makeInsertOplogEntry(
+        1, NamespaceString::makeSystemDotViewsNamespace(DatabaseName{dbName})));
     srcOps.push_back(
         makeInsertOplogEntry(2, NamespaceString::createNamespaceString_forTest(dbName, "bar")));
     _applier->enqueue(opCtx(), srcOps.cbegin(), srcOps.cend());
diff --git a/src/mongo/db/repl/oplog_interface_remote.cpp b/src/mongo/db/repl/oplog_interface_remote.cpp
index 1c5457ab9af..aea734b6c21 100644
--- a/src/mongo/db/repl/oplog_interface_remote.cpp
+++ b/src/mongo/db/repl/oplog_interface_remote.cpp
@@ -69,7 +69,7 @@ StatusWith<OplogInterface::Iterator::Value> OplogIteratorRemote::next() {
 
 OplogInterfaceRemote::OplogInterfaceRemote(HostAndPort hostAndPort,
                                            GetConnectionFn getConnection,
-                                           const std::string& collectionName,
+                                           StringData collectionName,
                                            int batchSize)
     : _hostAndPort(hostAndPort),
       _getConnection(getConnection),
diff --git a/src/mongo/db/repl/oplog_interface_remote.h b/src/mongo/db/repl/oplog_interface_remote.h
index 8200056f34f..5a6f7231e5e 100644
--- a/src/mongo/db/repl/oplog_interface_remote.h
+++ b/src/mongo/db/repl/oplog_interface_remote.h
@@ -52,7 +52,7 @@ public:
 
     OplogInterfaceRemote(HostAndPort hostAndPort,
                          GetConnectionFn getConnection,
-                         const std::string& collectionName,
+                         StringData collectionName,
                          int batchSize);
     std::string toString() const override;
     std::unique_ptr<OplogInterface::Iterator> makeIterator() const override;
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
index 1b659ed1b0a..23e0d77e581 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
@@ -779,7 +779,7 @@ StatusWith<OpTimeAndWallTime> ReplicationCoordinatorExternalStateImpl::loadLastO
         BSONObj oplogEntry;
 
         if (!writeConflictRetry(
-                opCtx, "Load last opTime", NamespaceString::kRsOplogNamespace.ns().c_str(), [&] {
+                opCtx, "Load last opTime", NamespaceString::kRsOplogNamespace.ns(), [&] {
                     return Helpers::getLast(opCtx, NamespaceString::kRsOplogNamespace, oplogEntry);
                 })) {
             return StatusWith<OpTimeAndWallTime>(ErrorCodes::NoMatchingDocument,
diff --git a/src/mongo/db/repl/rollback_source_impl.cpp b/src/mongo/db/repl/rollback_source_impl.cpp
index de16558a010..2559932a524 100644
--- a/src/mongo/db/repl/rollback_source_impl.cpp
+++ b/src/mongo/db/repl/rollback_source_impl.cpp
@@ -43,7 +43,7 @@ namespace repl {
 
 RollbackSourceImpl::RollbackSourceImpl(GetConnectionFn getConnection,
                                        const HostAndPort& source,
-                                       const std::string& collectionName,
+                                       StringData collectionName,
                                        int batchSize)
     : _getConnection(getConnection),
       _source(source),
diff --git a/src/mongo/db/repl/rollback_source_impl.h b/src/mongo/db/repl/rollback_source_impl.h
index 82c9135bf70..90147591c1e 100644
--- a/src/mongo/db/repl/rollback_source_impl.h
+++ b/src/mongo/db/repl/rollback_source_impl.h
@@ -55,7 +55,7 @@ public:
 
     RollbackSourceImpl(GetConnectionFn getConnection,
                        const HostAndPort& source,
-                       const std::string& collectionName,
+                       StringData collectionName,
                        int batchSize);
 
     const OplogInterface& getOplog() const override;
diff --git a/src/mongo/db/repl/storage_interface_impl_test.cpp b/src/mongo/db/repl/storage_interface_impl_test.cpp
index e586e013e40..f3e0fb62953 100644
--- a/src/mongo/db/repl/storage_interface_impl_test.cpp
+++ b/src/mongo/db/repl/storage_interface_impl_test.cpp
@@ -403,7 +403,7 @@ TEST_F(StorageInterfaceImplTest, InsertDocumentsReturnsOKWhenNoOperationsAreGive
 
     StorageInterfaceImpl storage;
     ASSERT_OK(storage.insertDocuments(opCtx, nss, {}));
-    ASSERT_OK(storage.insertDocuments(opCtx, {nss.db().toString(), *options.uuid}, {}));
+    ASSERT_OK(storage.insertDocuments(opCtx, {DatabaseName{nss.db()}, *options.uuid}, {}));
 }
 
 TEST_F(StorageInterfaceImplTest,
@@ -425,7 +425,7 @@ TEST_F(StorageInterfaceImplTest,
     // Again, but specify the collection with its UUID.
     ASSERT_EQ(ErrorCodes::InternalError,
               storage.insertDocuments(
-                  opCtx, {nss.db().toString(), *options.uuid}, transformInserts({op})));
+                  opCtx, {DatabaseName{nss.db()}, *options.uuid}, transformInserts({op})));
 }
 
 TEST_F(StorageInterfaceImplTest,
@@ -487,7 +487,7 @@ TEST_F(StorageInterfaceImplTest, InsertDocumentsSavesOperationsWhenCollSpecified
     auto op1 = makeOplogEntry({Timestamp(Seconds(1), 0), 1LL});
     auto op2 = makeOplogEntry({Timestamp(Seconds(1), 0), 1LL});
     ASSERT_OK(storage.insertDocuments(
-        opCtx, {nss.db().toString(), *options.uuid}, transformInserts({op1, op2})));
+        opCtx, {DatabaseName{nss.db()}, *options.uuid}, transformInserts({op1, op2})));
 
     // Check contents of oplog.
     _assertDocumentsInCollectionEquals(opCtx, nss, {op1.obj, op2.obj});
@@ -538,7 +538,7 @@ TEST_F(StorageInterfaceImplTest, InsertDocWorksWithExistingCappedCollectionSpeci
 
     StorageInterfaceImpl storage;
     ASSERT_OK(storage.insertDocument(opCtx,
-                                     {nss.db().toString(), *options.uuid},
+                                     {DatabaseName{nss.db()}, *options.uuid},
                                      {BSON("_id" << 1), Timestamp(1)},
                                      OpTime::kUninitializedTerm));
     AutoGetCollectionForReadCommand autoColl(opCtx, nss);
@@ -746,11 +746,11 @@ TEST_F(StorageInterfaceImplTest, DropCollectionWorksWithMissingCollection) {
     auto opCtx = getOperationContext();
     StorageInterfaceImpl storage;
     auto nss = makeNamespace(_agent);
-    ASSERT_FALSE(AutoGetDb(opCtx, nss.db(), MODE_IS).getDb());
+    ASSERT_FALSE(AutoGetDb(opCtx, DatabaseName{nss.db()}, MODE_IS).getDb());
     ASSERT_OK(storage.dropCollection(opCtx, nss));
     ASSERT_FALSE(AutoGetCollectionForReadCommand(opCtx, nss).getCollection());
     // Database should not be created after running dropCollection.
-    ASSERT_FALSE(AutoGetDb(opCtx, nss.db(), MODE_IS).getDb());
+    ASSERT_FALSE(AutoGetDb(opCtx, DatabaseName{nss.db()}, MODE_IS).getDb());
 }
 
 TEST_F(StorageInterfaceImplTest, DropCollectionWorksWithSystemCollection) {
@@ -2553,7 +2553,7 @@ TEST_F(StorageInterfaceImplTest, FindByIdReturnsNoSuchKeyWhenDocumentIsNotFound)
     ASSERT_EQUALS(ErrorCodes::NoSuchKey, storage.findById(opCtx, nss, doc2["_id"]).getStatus());
     ASSERT_EQUALS(
         ErrorCodes::NoSuchKey,
-        storage.findById(opCtx, {nss.db().toString(), *options.uuid}, doc2["_id"]).getStatus());
+        storage.findById(opCtx, {DatabaseName{nss.db()}, *options.uuid}, doc2["_id"]).getStatus());
 }
 
 TEST_F(StorageInterfaceImplTest, FindByIdReturnsDocumentWhenDocumentExists) {
@@ -2575,7 +2575,7 @@ TEST_F(StorageInterfaceImplTest, FindByIdReturnsDocumentWhenDocumentExists) {
     ASSERT_BSONOBJ_EQ(doc2, unittest::assertGet(storage.findById(opCtx, nss, doc2["_id"])));
     ASSERT_BSONOBJ_EQ(doc2,
                       unittest::assertGet(storage.findById(
-                          opCtx, {nss.db().toString(), *options.uuid}, doc2["_id"])));
+                          opCtx, {DatabaseName{nss.db()}, *options.uuid}, doc2["_id"])));
 }
 
 TEST_F(StorageInterfaceImplTest, FindByIdReturnsBadStatusIfPlanExecutorFails) {
@@ -2643,9 +2643,9 @@ TEST_F(StorageInterfaceImplTest, DeleteByIdReturnsNoSuchKeyWhenDocumentIsNotFoun
                                       {{doc1, Timestamp(0), OpTime::kUninitializedTerm},
                                        {doc3, Timestamp(0), OpTime::kUninitializedTerm}}));
     ASSERT_EQUALS(ErrorCodes::NoSuchKey, storage.deleteById(opCtx, nss, doc2["_id"]).getStatus());
-    ASSERT_EQUALS(
-        ErrorCodes::NoSuchKey,
-        storage.deleteById(opCtx, {nss.db().toString(), *options.uuid}, doc2["_id"]).getStatus());
+    ASSERT_EQUALS(ErrorCodes::NoSuchKey,
+                  storage.deleteById(opCtx, {DatabaseName{nss.db()}, *options.uuid}, doc2["_id"])
+                      .getStatus());
     _assertDocumentsInCollectionEquals(opCtx, nss, {doc1, doc3});
 }
 
@@ -2698,7 +2698,8 @@ TEST_F(StorageInterfaceImplTest,
     auto opCtx = getOperationContext();
     StorageInterfaceImpl storage;
     NamespaceString nss = NamespaceString::createNamespaceString_forTest("mydb.coll");
-    NamespaceString wrongColl(nss.db(), "wrongColl"_sd);
+    NamespaceString wrongColl =
+        NamespaceString::createNamespaceString_forTest(DatabaseName{nss.db()}, "wrongColl"_sd);
     ASSERT_OK(storage.createCollection(opCtx, nss, generateOptionsWithUuid()));
     auto doc = BSON("_id" << 0 << "x" << 1);
     auto status = storage.upsertById(opCtx, wrongColl, doc["_id"], doc);
@@ -2732,7 +2733,7 @@ TEST_F(StorageInterfaceImplTest, UpsertSingleDocumentReplacesExistingDocumentInC
 
     // Again, but specify the collection's UUID.
     ASSERT_OK(storage.upsertById(
-        opCtx, {nss.db().toString(), *options.uuid}, originalDoc["_id"], BSON("x" << 200)));
+        opCtx, {DatabaseName{nss.db()}, *options.uuid}, originalDoc["_id"], BSON("x" << 200)));
     _assertDocumentsInCollectionEquals(opCtx,
                                        nss,
                                        {BSON("_id" << 0 << "x" << 0),
@@ -2765,7 +2766,7 @@ TEST_F(StorageInterfaceImplTest, UpsertSingleDocumentInsertsNewDocumentInCollect
                                         BSON("_id" << 1 << "x" << 100)});
 
     ASSERT_OK(storage.upsertById(opCtx,
-                                 {nss.db().toString(), *options.uuid},
+                                 {DatabaseName{nss.db()}, *options.uuid},
                                  BSON("" << 3).firstElement(),
                                  BSON("x" << 300)));
     _assertDocumentsInCollectionEquals(opCtx,
@@ -2805,7 +2806,7 @@ TEST_F(StorageInterfaceImplTest,
                                         BSON("_id" << 2 << "x" << 2)});
 
     ASSERT_OK(storage.upsertById(
-        opCtx, {nss.db().toString(), *options.uuid}, originalDoc["_id"], BSON("x" << 200)));
+        opCtx, {DatabaseName{nss.db()}, *options.uuid}, originalDoc["_id"], BSON("x" << 200)));
     _assertDocumentsInCollectionEquals(opCtx,
                                        nss,
                                        {BSON("_id" << 0 << "x" << 0),
@@ -2828,7 +2829,7 @@ TEST_F(StorageInterfaceImplTest, UpsertSingleDocumentReturnsFailedToParseOnNonSi
                            "Unable to update document with a non-simple _id query:");
 
     ASSERT_EQ(storage.upsertById(opCtx,
-                                 {nss.db().toString(), *options.uuid},
+                                 {DatabaseName{nss.db()}, *options.uuid},
                                  BSON("" << BSON("$gt" << 3)).firstElement(),
                                  BSON("x" << 100)),
               ErrorCodes::InvalidIdField);
@@ -2850,7 +2851,7 @@ TEST_F(StorageInterfaceImplTest,
     ASSERT_STRING_CONTAINS(status.reason(),
                            "Unable to update document in a collection without an _id index.");
 
-    ASSERT_EQ(storage.upsertById(opCtx, {nss.db().toString(), *options.uuid}, doc["_id"], doc),
+    ASSERT_EQ(storage.upsertById(opCtx, {DatabaseName{nss.db()}, *options.uuid}, doc["_id"], doc),
               ErrorCodes::IndexNotFound);
 }
 
@@ -2872,7 +2873,7 @@ TEST_F(StorageInterfaceImplTest,
         "update specified as an array");
 
     ASSERT_THROWS_CODE(storage.upsertById(opCtx,
-                                          {nss.db().toString(), *options.uuid},
+                                          {DatabaseName{nss.db()}, *options.uuid},
                                           BSON("" << 1).firstElement(),
                                           unknownUpdateOp),
                        DBException,
@@ -2975,7 +2976,8 @@ TEST_F(StorageInterfaceImplTest, DeleteByFilterReturnsNamespaceNotFoundWhenColle
     auto opCtx = getOperationContext();
     StorageInterfaceImpl storage;
     NamespaceString nss = NamespaceString::createNamespaceString_forTest("mydb.coll");
-    NamespaceString wrongColl(nss.db(), "wrongColl"_sd);
+    NamespaceString wrongColl =
+        NamespaceString::createNamespaceString_forTest(DatabaseName{nss.db()}, "wrongColl"_sd);
     ASSERT_OK(storage.createCollection(opCtx, nss, generateOptionsWithUuid()));
     auto filter = BSON("x" << 1);
     auto status = storage.deleteByFilter(opCtx, wrongColl, filter);
@@ -3145,7 +3147,8 @@ TEST_F(StorageInterfaceImplTest,
     auto opCtx = getOperationContext();
     StorageInterfaceImpl storage;
     auto nss = makeNamespace(_agent);
-    NamespaceString wrongColl(nss.db(), "wrongColl"_sd);
+    NamespaceString wrongColl =
+        NamespaceString::createNamespaceString_forTest(DatabaseName{nss.db()}, "wrongColl"_sd);
     ASSERT_OK(storage.createCollection(opCtx, nss, generateOptionsWithUuid()));
     ASSERT_EQUALS(ErrorCodes::NamespaceNotFound,
                   storage.getCollectionCount(opCtx, wrongColl).getStatus());
@@ -3188,7 +3191,8 @@ TEST_F(StorageInterfaceImplTest,
     auto opCtx = getOperationContext();
     StorageInterfaceImpl storage;
     auto nss = makeNamespace(_agent);
-    NamespaceString wrongColl(nss.db(), "wrongColl"_sd);
+    NamespaceString wrongColl =
+        NamespaceString::createNamespaceString_forTest(DatabaseName{nss.db()}, "wrongColl"_sd);
     ASSERT_OK(storage.createCollection(opCtx, nss, generateOptionsWithUuid()));
     ASSERT_EQUALS(ErrorCodes::NamespaceNotFound, storage.setCollectionCount(opCtx, wrongColl, 3));
 }
@@ -3206,7 +3210,8 @@ TEST_F(StorageInterfaceImplTest,
     auto opCtx = getOperationContext();
     StorageInterfaceImpl storage;
     auto nss = makeNamespace(_agent);
-    NamespaceString wrongColl(nss.db(), "wrongColl"_sd);
+    NamespaceString wrongColl =
+        NamespaceString::createNamespaceString_forTest(DatabaseName{nss.db()}, "wrongColl"_sd);
     ASSERT_OK(storage.createCollection(opCtx, nss, generateOptionsWithUuid()));
     ASSERT_EQUALS(ErrorCodes::NamespaceNotFound,
                   storage.getCollectionSize(opCtx, wrongColl).getStatus());
@@ -3249,7 +3254,8 @@ TEST_F(StorageInterfaceImplTest, SetIndexIsMultikeyReturnsNamespaceNotFoundForMi
     auto opCtx = getOperationContext();
     StorageInterfaceImpl storage;
     auto nss = makeNamespace(_agent);
-    NamespaceString wrongColl(nss.db(), "wrongColl"_sd);
+    NamespaceString wrongColl =
+        NamespaceString::createNamespaceString_forTest(DatabaseName{nss.db()}, "wrongColl"_sd);
     ASSERT_OK(storage.createCollection(opCtx, nss, CollectionOptions()));
     ASSERT_EQUALS(
         ErrorCodes::NamespaceNotFound,
@@ -3262,7 +3268,8 @@ TEST_F(StorageInterfaceImplTest, SetIndexIsMultikeyLooksUpCollectionByUUID) {
     auto nss = makeNamespace(_agent);
     auto options = generateOptionsWithUuid();
     ASSERT_OK(storage.createCollection(opCtx, nss, options));
-    NamespaceString wrongColl(nss.db(), "wrongColl"_sd);
+    NamespaceString wrongColl =
+        NamespaceString::createNamespaceString_forTest(DatabaseName{nss.db()}, "wrongColl"_sd);
     ASSERT_EQUALS(ErrorCodes::IndexNotFound,
                   storage.setIndexIsMultikey(
                       opCtx, wrongColl, *options.uuid, "foo", {}, {}, Timestamp(3, 3)));
diff --git a/src/mongo/db/repl/tenant_collection_cloner.cpp b/src/mongo/db/repl/tenant_collection_cloner.cpp
index ff5899c20ef..7bb28eb869e 100644
--- a/src/mongo/db/repl/tenant_collection_cloner.cpp
+++ b/src/mongo/db/repl/tenant_collection_cloner.cpp
@@ -104,7 +104,7 @@ TenantCollectionCloner::TenantCollectionCloner(const NamespaceString& sourceNss,
     invariant(ClonerUtils::isNamespaceForTenant(sourceNss, tenantId));
     invariant(collectionOptions.uuid);
     _sourceDbAndUuid = NamespaceStringOrUUID(sourceNss.dbName(), *collectionOptions.uuid);
-    _stats.ns = _sourceNss.ns();
+    _stats.ns = _sourceNss.ns().toString();
 }
 
 BaseCloner::ClonerStages TenantCollectionCloner::getStages() {
diff --git a/src/mongo/db/repl/tenant_database_cloner.cpp b/src/mongo/db/repl/tenant_database_cloner.cpp
index ca06222ceaa..6551c7838d9 100644
--- a/src/mongo/db/repl/tenant_database_cloner.cpp
+++ b/src/mongo/db/repl/tenant_database_cloner.cpp
@@ -304,7 +304,7 @@ void TenantDatabaseCloner::postStage() {
         _stats.collectionStats.reserve(_collections.size());
         for (const auto& coll : _collections) {
             _stats.collectionStats.emplace_back();
-            _stats.collectionStats.back().ns = coll.first.ns();
+            _stats.collectionStats.back().ns = coll.first.ns().toString();
         }
     }
     for (const auto& coll : _collections) {
diff --git a/src/mongo/db/repl/tenant_file_importer_service.cpp b/src/mongo/db/repl/tenant_file_importer_service.cpp
index b88437df094..9764eb86820 100644
--- a/src/mongo/db/repl/tenant_file_importer_service.cpp
+++ b/src/mongo/db/repl/tenant_file_importer_service.cpp
@@ -318,7 +318,7 @@ void TenantFileImporterService::_voteImportedFiles(OperationContext* opCtx,
 
     auto voteResponse = replCoord->runCmdOnPrimaryAndAwaitResponse(
         opCtx,
-        DatabaseName::kAdmin.db(),
+        DatabaseName::kAdmin.db().toString(),
         cmd.toBSON({}),
         [](executor::TaskExecutor::CallbackHandle handle) {},
         [](executor::TaskExecutor::CallbackHandle handle) {});
diff --git a/src/mongo/db/repl/tenant_migration_access_blocker_util.cpp b/src/mongo/db/repl/tenant_migration_access_blocker_util.cpp
index 95aeb6312fe..c7f16a6604b 100644
--- a/src/mongo/db/repl/tenant_migration_access_blocker_util.cpp
+++ b/src/mongo/db/repl/tenant_migration_access_blocker_util.cpp
@@ -714,7 +714,7 @@ boost::optional<std::string> extractTenantFromDatabaseName(const DatabaseName& d
         return boost::none;
     }
 
-    return dbName.db().substr(0, pos);
+    return dbName.db().substr(0, pos).toString();
 }
 
 }  // namespace tenant_migration_access_blocker
diff --git a/src/mongo/db/repl/tenant_migration_access_blocker_util_test.cpp b/src/mongo/db/repl/tenant_migration_access_blocker_util_test.cpp
index 229c7981668..2d3a99956c1 100644
--- a/src/mongo/db/repl/tenant_migration_access_blocker_util_test.cpp
+++ b/src/mongo/db/repl/tenant_migration_access_blocker_util_test.cpp
@@ -95,7 +95,8 @@ TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveShardMergeTrueWithDonor) {
         std::make_shared<TenantMigrationDonorAccessBlocker>(getServiceContext(), UUID::gen());
     TenantMigrationAccessBlockerRegistry::get(getServiceContext())
         .addGlobalDonorAccessBlocker(donorMtab);
-    ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), "local"_sd));
+    ASSERT_FALSE(
+        tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), DatabaseName::kLocal));
     ASSERT(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), kTenantDB));
 }
 
@@ -129,7 +130,8 @@ TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveShardMergeTrueWithBoth) {
     TenantMigrationAccessBlockerRegistry::get(getServiceContext())
         .addGlobalDonorAccessBlocker(donorMtab);
     // Access blocker do not impact ns without tenants.
-    ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), "config"_sd));
+    ASSERT_FALSE(
+        tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), DatabaseName::kConfig));
     ASSERT(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), kTenantDB));
 }
 
@@ -138,7 +140,8 @@ TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveTenantMigrationDonorFalseF
         std::make_shared<TenantMigrationDonorAccessBlocker>(getServiceContext(), UUID::gen());
     TenantMigrationAccessBlockerRegistry::get(getServiceContext()).add(kTenantId, donorMtab);
 
-    ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), StringData()));
+    ASSERT_FALSE(
+        tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), DatabaseName::kEmpty));
 }
 
 TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveShardMergeDonorFalseForNoDbName) {
@@ -146,14 +149,16 @@ TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveShardMergeDonorFalseForNoD
         std::make_shared<TenantMigrationDonorAccessBlocker>(getServiceContext(), UUID::gen());
     TenantMigrationAccessBlockerRegistry::get(getServiceContext())
         .addGlobalDonorAccessBlocker(donorMtab);
-    ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), StringData()));
+    ASSERT_FALSE(
+        tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), DatabaseName::kEmpty));
 }
 
 TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveShardMergeRecipientFalseForNoDbName) {
     auto recipientMtab =
         std::make_shared<TenantMigrationRecipientAccessBlocker>(getServiceContext(), UUID::gen());
     TenantMigrationAccessBlockerRegistry::get(getServiceContext()).add(kTenantId, recipientMtab);
-    ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), StringData()));
+    ASSERT_FALSE(
+        tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), DatabaseName::kEmpty));
 }
 
 TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveTenantMigrationFalseForUnrelatedDb) {
@@ -165,7 +170,8 @@ TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveTenantMigrationFalseForUnr
         std::make_shared<TenantMigrationDonorAccessBlocker>(getServiceContext(), UUID::gen());
     TenantMigrationAccessBlockerRegistry::get(getServiceContext()).add(kTenantId, donorMtab);
 
-    ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), "config"_sd));
+    ASSERT_FALSE(
+        tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), DatabaseName::kConfig));
 }
 
 TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveTenantMigrationFalseAfterRemoveWithBoth) {
@@ -202,20 +208,23 @@ TEST_F(TenantMigrationAccessBlockerUtilTest, HasActiveShardMergeFalseAfterRemove
         .addGlobalDonorAccessBlocker(donorMtab);
 
     ASSERT(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), kTenantDB));
-    ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), "admin"_sd));
+    ASSERT_FALSE(
+        tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), DatabaseName::kAdmin));
 
     // Remove donor, should still be a migration for the tenants migrating to the recipient.
     TenantMigrationAccessBlockerRegistry::get(getServiceContext())
         .removeAccessBlockersForMigration(migrationId,
                                           TenantMigrationAccessBlocker::BlockerType::kDonor);
     ASSERT(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), kTenantDB));
-    ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), "admin"_sd));
+    ASSERT_FALSE(
+        tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), DatabaseName::kAdmin));
 
     // Remove recipient, there should be no migration.
     TenantMigrationAccessBlockerRegistry::get(getServiceContext())
         .remove(kTenantId, TenantMigrationAccessBlocker::BlockerType::kRecipient);
     ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), kTenantDB));
-    ASSERT_FALSE(tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), "admin"_sd));
+    ASSERT_FALSE(
+        tenant_migration_access_blocker::hasActiveTenantMigration(opCtx(), DatabaseName::kAdmin));
 }
 
 TEST_F(TenantMigrationAccessBlockerUtilTest, TestValidateNssBeingMigrated) {
diff --git a/src/mongo/db/s/analyze_shard_key_cmd_util.cpp b/src/mongo/db/s/analyze_shard_key_cmd_util.cpp
index 1c554a800fe..4bfbe6c84c5 100644
--- a/src/mongo/db/s/analyze_shard_key_cmd_util.cpp
+++ b/src/mongo/db/s/analyze_shard_key_cmd_util.cpp
@@ -705,7 +705,8 @@ std::pair<BSONObj, Timestamp> generateSplitPoints(OperationContext* opCtx,
             str::stream() << "Cannot analyze a shard key for a non-existing collection",
             origCollUuid);
     // Perform best-effort validation that the collection has not been dropped and recreated.
-    uassert(CollectionUUIDMismatchInfo(nss.db(), collUuid, nss.coll().toString(), boost::none),
+    uassert(CollectionUUIDMismatchInfo(
+                DatabaseName{nss.db()}, collUuid, nss.coll().toString(), boost::none),
             str::stream() << "Found that the collection UUID has changed from " << collUuid
                           << " to " << origCollUuid << " since the command started",
             origCollUuid == collUuid);
@@ -823,7 +824,8 @@ KeyCharacteristicsMetrics calculateKeyCharacteristicsMetrics(OperationContext* o
                 str::stream() << "Cannot analyze a shard key for a non-existing collection",
                 collection);
         // Perform best-effort validation that the collection has not been dropped and recreated.
-        uassert(CollectionUUIDMismatchInfo(nss.db(), collUuid, nss.coll().toString(), boost::none),
+        uassert(CollectionUUIDMismatchInfo(
+                    DatabaseName{nss.db()}, collUuid, nss.coll().toString(), boost::none),
                 str::stream() << "Found that the collection UUID has changed from " << collUuid
                               << " to " << collection->uuid() << " since the command started",
                 collection->uuid() == collUuid);
diff --git a/src/mongo/db/s/balancer/migration_test_fixture.cpp b/src/mongo/db/s/balancer/migration_test_fixture.cpp
index e5b51181003..ed45e996856 100644
--- a/src/mongo/db/s/balancer/migration_test_fixture.cpp
+++ b/src/mongo/db/s/balancer/migration_test_fixture.cpp
@@ -86,9 +86,9 @@ void MigrationTestFixture::setUpZones(const NamespaceString& collName,
                                       const StringMap<ChunkRange>& zoneChunkRanges) {
     for (auto const& zoneChunkRange : zoneChunkRanges) {
         BSONObjBuilder zoneDocBuilder;
-        zoneDocBuilder.append(
-            "_id",
-            BSON(TagsType::ns(collName.ns()) << TagsType::min(zoneChunkRange.second.getMin())));
+        zoneDocBuilder.append("_id",
+                              BSON(TagsType::ns(collName.ns().toString())
+                                   << TagsType::min(zoneChunkRange.second.getMin())));
         zoneDocBuilder.append(TagsType::ns(), collName.ns());
         zoneDocBuilder.append(TagsType::min(), zoneChunkRange.second.getMin());
         zoneDocBuilder.append(TagsType::max(), zoneChunkRange.second.getMax());
diff --git a/src/mongo/db/s/config/configsvr_add_shard_command.cpp b/src/mongo/db/s/config/configsvr_add_shard_command.cpp
index a9ef2a14dc2..11ccdd19b06 100644
--- a/src/mongo/db/s/config/configsvr_add_shard_command.cpp
+++ b/src/mongo/db/s/config/configsvr_add_shard_command.cpp
@@ -86,7 +86,7 @@ Status notifyShardsOfSecondShardIfNeeded(OperationContext* opCtx) {
     // Set the cluster parameter to disallow direct writes to shards
     ConfigsvrSetClusterParameter configsvrSetClusterParameter(
         BSON("shardedClusterCardinalityForDirectConns" << BSON("hasTwoOrMoreShards" << true)));
-    configsvrSetClusterParameter.setDbName(DatabaseName(boost::none, "admin"));
+    configsvrSetClusterParameter.setDbName(DatabaseName::kAdmin);
 
     const auto cmdResponse = shardRegistry->getConfigShard()->runCommandWithFixedRetryAttempts(
         opCtx,
diff --git a/src/mongo/db/s/config/configsvr_remove_tags_command.cpp b/src/mongo/db/s/config/configsvr_remove_tags_command.cpp
index 8f5fd5f7ec3..8dd75292aa7 100644
--- a/src/mongo/db/s/config/configsvr_remove_tags_command.cpp
+++ b/src/mongo/db/s/config/configsvr_remove_tags_command.cpp
@@ -95,7 +95,7 @@ public:
                 uassertStatusOK(catalogClient->removeConfigDocuments(
                     newOpCtxPtr.get(),
                     TagsType::ConfigNS,
-                    BSON(TagsType::ns(nss.ns())),
+                    BSON(TagsType::ns(nss.ns().toString())),
                     ShardingCatalogClient::kLocalWriteConcern));
             }
 
diff --git a/src/mongo/db/s/config/initial_split_policy_test.cpp b/src/mongo/db/s/config/initial_split_policy_test.cpp
index 923a59e01ea..648cbcb9719 100644
--- a/src/mongo/db/s/config/initial_split_policy_test.cpp
+++ b/src/mongo/db/s/config/initial_split_policy_test.cpp
@@ -394,8 +394,8 @@ public:
 
     TagsType makeTag(const ChunkRange range, std::string zoneName) {
         BSONObjBuilder tagDocBuilder;
-        tagDocBuilder.append("_id",
-                             BSON(TagsType::ns(nss().ns()) << TagsType::min(range.getMin())));
+        tagDocBuilder.append(
+            "_id", BSON(TagsType::ns(nss().ns().toString()) << TagsType::min(range.getMin())));
         tagDocBuilder.append(TagsType::ns(), nss().ns());
         tagDocBuilder.append(TagsType::min(), range.getMin());
         tagDocBuilder.append(TagsType::max(), range.getMax());
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_assign_key_range_to_zone_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_assign_key_range_to_zone_test.cpp
index 377d17292ff..e486fb7daad 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_assign_key_range_to_zone_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_assign_key_range_to_zone_test.cpp
@@ -225,12 +225,13 @@ TEST_F(AssignKeyRangeToZoneTestFixture, RemoveZoneWithDollarPrefixedShardKeysSho
 
     // Manually insert a zone with illegal keys in order to bypass the checks performed by
     // assignKeyRangeToZone
-    BSONObj updateQuery(BSON("_id" << BSON(TagsType::ns(shardedNS().ns())
+    BSONObj updateQuery(BSON("_id" << BSON(TagsType::ns(shardedNS().ns().toString())
                                            << TagsType::min(zoneWithDollarKeys.getMin()))));
 
     BSONObjBuilder updateBuilder;
-    updateBuilder.append(
-        "_id", BSON(TagsType::ns(shardedNS().ns()) << TagsType::min(zoneWithDollarKeys.getMin())));
+    updateBuilder.append("_id",
+                         BSON(TagsType::ns(shardedNS().ns().toString())
+                              << TagsType::min(zoneWithDollarKeys.getMin())));
     updateBuilder.append(TagsType::ns(), shardedNS().ns());
     updateBuilder.append(TagsType::min(), zoneWithDollarKeys.getMin());
     updateBuilder.append(TagsType::max(), zoneWithDollarKeys.getMax());
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_merge_chunks_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_merge_chunks_test.cpp
index 1f260d2fea4..2dfc3f40312 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_merge_chunks_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_merge_chunks_test.cpp
@@ -893,7 +893,7 @@ protected:
         size_t numMerges = 0;
         for (const auto& chunkDiff : chunksDiff) {
             BSONObjBuilder query;
-            query << ChangeLogType::what("merge") << ChangeLogType::ns(nss.ns());
+            query << ChangeLogType::what("merge") << ChangeLogType::ns(nss.ns().toString());
             chunkDiff.getVersion().serialize("details.mergedVersion", &query);
 
             auto response = assertGet(getConfigShard()->exhaustiveFindOnConfig(
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_zone_operations.cpp b/src/mongo/db/s/config/sharding_catalog_manager_zone_operations.cpp
index 4fd943c3bfb..aeb3bcb7522 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_zone_operations.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_zone_operations.cpp
@@ -74,7 +74,7 @@ Status checkForOverlappingZonedKeyRange(OperationContext* opCtx,
                                                           kConfigPrimarySelector,
                                                           repl::ReadConcernLevel::kLocalReadConcern,
                                                           TagsType::ConfigNS,
-                                                          BSON(TagsType::ns(nss.ns())),
+                                                          BSON(TagsType::ns(nss.ns().toString())),
                                                           BSONObj(),
                                                           0);
     if (!tagStatus.isOK()) {
@@ -362,7 +362,7 @@ void ShardingCatalogManager::assignKeyRangeToZone(OperationContext* opCtx,
     uassertStatusOK(_localCatalogClient->updateConfigDocument(
         opCtx,
         TagsType::ConfigNS,
-        BSON(TagsType::ns(nss.ns()) << TagsType::min(actualRange.getMin())),
+        BSON(TagsType::ns(nss.ns().toString()) << TagsType::min(actualRange.getMin())),
         updateBuilder.obj(),
         true,
         kNoWaitWriteConcern));
diff --git a/src/mongo/db/s/configure_query_analyzer_cmd.cpp b/src/mongo/db/s/configure_query_analyzer_cmd.cpp
index b212ab96f49..5432dbbdf79 100644
--- a/src/mongo/db/s/configure_query_analyzer_cmd.cpp
+++ b/src/mongo/db/s/configure_query_analyzer_cmd.cpp
@@ -62,7 +62,7 @@ constexpr int kMaxSampleRate = 1'000'000;
 StatusWith<UUID> validateCollectionOptionsOnPrimaryShard(OperationContext* opCtx,
                                                          const NamespaceString& nss) {
     ListCollections listCollections;
-    listCollections.setDbName(nss.db());
+    listCollections.setDbName(DatabaseName{nss.db()});
     listCollections.setFilter(BSON("name" << nss.coll()));
     auto listCollectionsCmdObj =
         CommandHelpers::filterCommandRequestForPassthrough(listCollections.toBSON({}));
diff --git a/src/mongo/db/s/drop_database_coordinator.cpp b/src/mongo/db/s/drop_database_coordinator.cpp
index 42396bef6b3..6189f2ecbf4 100644
--- a/src/mongo/db/s/drop_database_coordinator.cpp
+++ b/src/mongo/db/s/drop_database_coordinator.cpp
@@ -407,7 +407,7 @@ ExecutorFuture<void> DropDatabaseCoordinator::_runImpl(
                     }
 
                     auto dropDatabaseParticipantCmd = ShardsvrDropDatabaseParticipant();
-                    dropDatabaseParticipantCmd.setDbName(_dbName);
+                    dropDatabaseParticipantCmd.setDbName(DatabaseName{_dbName});
                     const auto cmdObj = CommandHelpers::appendMajorityWriteConcern(
                         dropDatabaseParticipantCmd.toBSON({}));
 
@@ -494,7 +494,7 @@ ExecutorFuture<void> DropDatabaseCoordinator::_runImpl(
                 FlushDatabaseCacheUpdatesWithWriteConcern flushDbCacheUpdatesCmd(
                     _dbName.toString());
                 flushDbCacheUpdatesCmd.setSyncFromConfig(true);
-                flushDbCacheUpdatesCmd.setDbName(_dbName);
+                flushDbCacheUpdatesCmd.setDbName(DatabaseName{_dbName});
 
                 IgnoreAPIParametersBlock ignoreApiParametersBlock{opCtx};
                 sharding_ddl_util::sendAuthenticatedCommandToShards(
diff --git a/src/mongo/db/s/flush_database_cache_updates_command.cpp b/src/mongo/db/s/flush_database_cache_updates_command.cpp
index 3509a8e9303..33d2f57b374 100644
--- a/src/mongo/db/s/flush_database_cache_updates_command.cpp
+++ b/src/mongo/db/s/flush_database_cache_updates_command.cpp
@@ -143,7 +143,7 @@ public:
                     "Can't call _flushDatabaseCacheUpdates if in read-only mode",
                     !opCtx->readOnly());
 
-            if (_dbName() == DatabaseName::kAdmin || _dbName() == DatabaseName::kConfig) {
+            if (_dbName() == DatabaseName::kAdmin.db() || _dbName() == DatabaseName::kConfig.db()) {
                 // The admin and config databases have fixed metadata that does not need to be
                 // refreshed.
 
@@ -157,7 +157,8 @@ public:
                                 1,
                                 "Inserting a database collection entry with fixed metadata",
                                 "db"_attr = _dbName());
-                    uassertStatusOK(insertDatabaseEntryForBackwardCompatibility(opCtx, _dbName()));
+                    uassertStatusOK(insertDatabaseEntryForBackwardCompatibility(
+                        opCtx, DatabaseName{_dbName()}));
                 }
 
                 return;
@@ -166,7 +167,7 @@ public:
             boost::optional<SharedSemiFuture<void>> criticalSectionSignal;
 
             {
-                AutoGetDb autoDb(opCtx, _dbName(), MODE_IS);
+                AutoGetDb autoDb(opCtx, DatabaseName{_dbName()}, MODE_IS);
 
                 // If the primary is in the critical section, secondaries must wait for the commit
                 // to finish on the primary in case a secondary's caller has an afterClusterTime
diff --git a/src/mongo/db/s/global_index/global_index_cloning_service_test.cpp b/src/mongo/db/s/global_index/global_index_cloning_service_test.cpp
index 96b8e60993a..f85acd5834a 100644
--- a/src/mongo/db/s/global_index/global_index_cloning_service_test.cpp
+++ b/src/mongo/db/s/global_index/global_index_cloning_service_test.cpp
@@ -307,7 +307,7 @@ public:
         replaceFetcherResultList(std::move(fetcherResults));
 
         CreateGlobalIndex createGlobalIndex(_indexCollectionUUID);
-        createGlobalIndex.setDbName({boost::none, "admin"});
+        createGlobalIndex.setDbName(DatabaseName::kAdmin);
         BSONObj cmdResult;
         auto success =
             client.runCommand({boost::none, "admin"}, createGlobalIndex.toBSON({}), cmdResult);
diff --git a/src/mongo/db/s/global_index/global_index_inserter.cpp b/src/mongo/db/s/global_index/global_index_inserter.cpp
index 6a7ba103788..8ebadf1dd90 100644
--- a/src/mongo/db/s/global_index/global_index_inserter.cpp
+++ b/src/mongo/db/s/global_index/global_index_inserter.cpp
@@ -91,7 +91,7 @@ void GlobalIndexInserter::processDoc(OperationContext* opCtx,
 
                     InsertGlobalIndexKey globalIndexEntryInsert(_indexUUID);
                     // Note: dbName is unused by command but required by idl.
-                    globalIndexEntryInsert.setDbName({boost::none, "admin"});
+                    globalIndexEntryInsert.setDbName(DatabaseName::kAdmin);
                     globalIndexEntryInsert.setGlobalIndexKeyEntry(
                         GlobalIndexKeyEntry(indexKeyValues, documentKey));
 
diff --git a/src/mongo/db/s/global_index/global_index_inserter_test.cpp b/src/mongo/db/s/global_index/global_index_inserter_test.cpp
index c65ca491f74..ee70e6edb67 100644
--- a/src/mongo/db/s/global_index/global_index_inserter_test.cpp
+++ b/src/mongo/db/s/global_index/global_index_inserter_test.cpp
@@ -76,7 +76,7 @@ public:
         _executor = makeTaskExecutorForCloner();
 
         CreateGlobalIndex createGlobalIndex(_indexUUID);
-        createGlobalIndex.setDbName({boost::none, "admin"});
+        createGlobalIndex.setDbName(DatabaseName::kAdmin);
         BSONObj cmdResult;
         auto success =
             client.runCommand({boost::none, "admin"}, createGlobalIndex.toBSON({}), cmdResult);
diff --git a/src/mongo/db/s/migration_destination_manager.cpp b/src/mongo/db/s/migration_destination_manager.cpp
index 81a062c2491..34467541e38 100644
--- a/src/mongo/db/s/migration_destination_manager.cpp
+++ b/src/mongo/db/s/migration_destination_manager.cpp
@@ -1700,7 +1700,7 @@ bool MigrationDestinationManager::_applyMigrateOp(OperationContext* opCtx, const
     if (xfer["deleted"].isABSONObj()) {
         boost::optional<RemoveSaver> rs;
         if (serverGlobalParams.moveParanoia) {
-            rs.emplace("moveChunk", _nss.ns(), "removedDuring");
+            rs.emplace("moveChunk", _nss.ns().toString(), "removedDuring");
         }
 
         BSONObjIterator i(xfer["deleted"].Obj());
diff --git a/src/mongo/db/s/move_primary/move_primary_donor_service.cpp b/src/mongo/db/s/move_primary/move_primary_donor_service.cpp
index ae82cda7b07..486dfbc2f93 100644
--- a/src/mongo/db/s/move_primary/move_primary_donor_service.cpp
+++ b/src/mongo/db/s/move_primary/move_primary_donor_service.cpp
@@ -277,7 +277,7 @@ void MovePrimaryDonorExternalState::syncDataOnRecipient(OperationContext* opCtx,
                                                         boost::optional<Timestamp> timestamp) {
     MovePrimaryRecipientSyncData request;
     request.setMovePrimaryCommonMetadata(getMetadata());
-    request.setDbName(getMetadata().getDatabaseName().db());
+    request.setDbName(DatabaseName{getMetadata().getDatabaseName().db()});
     if (timestamp) {
         request.setReturnAfterReachingDonorTimestamp(*timestamp);
     }
@@ -287,14 +287,14 @@ void MovePrimaryDonorExternalState::syncDataOnRecipient(OperationContext* opCtx,
 void MovePrimaryDonorExternalState::abortMigrationOnRecipient(OperationContext* opCtx) {
     MovePrimaryRecipientAbortMigration request;
     request.setMovePrimaryCommonMetadata(getMetadata());
-    request.setDbName(getMetadata().getDatabaseName().db());
+    request.setDbName(DatabaseName{getMetadata().getDatabaseName().db()});
     _runCommandOnRecipient(opCtx, request.toBSON({}));
 }
 
 void MovePrimaryDonorExternalState::forgetMigrationOnRecipient(OperationContext* opCtx) {
     MovePrimaryRecipientForgetMigration request;
     request.setMovePrimaryCommonMetadata(getMetadata());
-    request.setDbName(getMetadata().getDatabaseName().db());
+    request.setDbName(DatabaseName{getMetadata().getDatabaseName().db()});
     _runCommandOnRecipient(opCtx, request.toBSON({}));
 }
 
@@ -364,7 +364,7 @@ bool MovePrimaryDonor::_matchesArguments(const std::shared_ptr<MovePrimaryDonor>
                                          const DatabaseName& dbName,
                                          const ShardId& toShard) {
     const auto& metadata = instance->getMetadata();
-    if (dbName != metadata.getDatabaseName().db()) {
+    if (dbName != metadata.getDatabaseName().dbName()) {
         return false;
     }
     if (toShard.toString() != metadata.getToShardName()) {
diff --git a/src/mongo/db/s/move_primary_coordinator.cpp b/src/mongo/db/s/move_primary_coordinator.cpp
index f8a214246e3..89b2f12b9a0 100644
--- a/src/mongo/db/s/move_primary_coordinator.cpp
+++ b/src/mongo/db/s/move_primary_coordinator.cpp
@@ -592,7 +592,7 @@ std::vector<NamespaceString> MovePrimaryCoordinator::cloneDataToRecipient(
     const auto cloneResponse =
         toShard->runCommand(opCtx,
                             ReadPreferenceSetting(ReadPreference::PrimaryOnly),
-                            DatabaseName::kAdmin.db(),
+                            DatabaseName::kAdmin.db().toString(),
                             cloneCommand,
                             Shard::RetryPolicy::kNoRetry);
 
@@ -641,7 +641,7 @@ void MovePrimaryCoordinator::commitMetadataToConfig(
     const auto commitResponse =
         config->runCommandWithFixedRetryAttempts(opCtx,
                                                  ReadPreferenceSetting(ReadPreference::PrimaryOnly),
-                                                 DatabaseName::kAdmin.db(),
+                                                 DatabaseName::kAdmin.db().toString(),
                                                  commitCommand,
                                                  Shard::RetryPolicy::kIdempotent);
 
diff --git a/src/mongo/db/s/move_primary_source_manager.cpp b/src/mongo/db/s/move_primary_source_manager.cpp
index fcf62395449..5ad4ac0426a 100644
--- a/src/mongo/db/s/move_primary_source_manager.cpp
+++ b/src/mongo/db/s/move_primary_source_manager.cpp
@@ -345,7 +345,8 @@ Status MovePrimarySourceManager::_commitOnConfig(OperationContext* opCtx,
     notifyChangeStreamsOnMovePrimary(opCtx, getNss().dbName(), _fromShard, _toShard);
 
     const auto commitStatus = [&] {
-        ConfigsvrCommitMovePrimary commitRequest(_dbname, expectedDbVersion, _toShard);
+        ConfigsvrCommitMovePrimary commitRequest(
+            DatabaseName{_dbname}, expectedDbVersion, _toShard);
         commitRequest.setDbName(DatabaseName::kAdmin);
 
         const auto commitResponse =
@@ -465,7 +466,7 @@ Status MovePrimarySourceManager::cleanStaleData(OperationContext* opCtx) {
     DBDirectClient client(opCtx);
     for (auto& coll : _clonedColls) {
         BSONObj dropCollResult;
-        client.runCommand(_dbname, BSON("drop" << coll.coll()), dropCollResult);
+        client.runCommand(DatabaseName{_dbname}, BSON("drop" << coll.coll()), dropCollResult);
         Status dropStatus = getStatusFromCommandResult(dropCollResult);
         if (!dropStatus.isOK()) {
             LOGV2(22045,
diff --git a/src/mongo/db/s/move_timing_helper.cpp b/src/mongo/db/s/move_timing_helper.cpp
index 1494da2882e..2d78ba65b8f 100644
--- a/src/mongo/db/s/move_timing_helper.cpp
+++ b/src/mongo/db/s/move_timing_helper.cpp
@@ -45,7 +45,7 @@ namespace mongo {
 
 MoveTimingHelper::MoveTimingHelper(OperationContext* opCtx,
                                    const std::string& where,
-                                   const std::string& ns,
+                                   StringData ns,
                                    const boost::optional<BSONObj>& min,
                                    const boost::optional<BSONObj>& max,
                                    int totalNumSteps,
diff --git a/src/mongo/db/s/move_timing_helper.h b/src/mongo/db/s/move_timing_helper.h
index e7f0de9ca2a..763268bab05 100644
--- a/src/mongo/db/s/move_timing_helper.h
+++ b/src/mongo/db/s/move_timing_helper.h
@@ -44,7 +44,7 @@ class MoveTimingHelper {
 public:
     MoveTimingHelper(OperationContext* opCtx,
                      const std::string& where,
-                     const std::string& ns,
+                     StringData ns,
                      const boost::optional<BSONObj>& min,
                      const boost::optional<BSONObj>& max,
                      int totalNumSteps,
diff --git a/src/mongo/db/s/op_observer_sharding_impl.cpp b/src/mongo/db/s/op_observer_sharding_impl.cpp
index ee75c265bce..b1cb1fa739c 100644
--- a/src/mongo/db/s/op_observer_sharding_impl.cpp
+++ b/src/mongo/db/s/op_observer_sharding_impl.cpp
@@ -121,7 +121,7 @@ void OpObserverShardingImpl::shardObserveInsertsOp(
 
     auto* const css = shardingWriteRouter.getCss();
     css->checkShardVersionOrThrow(opCtx);
-    DatabaseShardingState::assertMatchingDbVersion(opCtx, nss.db());
+    DatabaseShardingState::assertMatchingDbVersion(opCtx, DatabaseName{nss.db()});
 
     auto* const csr = checked_cast<CollectionShardingRuntime*>(css);
     auto metadata = csr->getCurrentMetadataIfKnown();
@@ -163,7 +163,7 @@ void OpObserverShardingImpl::shardObserveUpdateOp(OperationContext* opCtx,
                                                   const bool inMultiDocumentTransaction) {
     auto* const css = shardingWriteRouter.getCss();
     css->checkShardVersionOrThrow(opCtx);
-    DatabaseShardingState::assertMatchingDbVersion(opCtx, nss.db());
+    DatabaseShardingState::assertMatchingDbVersion(opCtx, DatabaseName{nss.db()});
 
     auto* const csr = checked_cast<CollectionShardingRuntime*>(css);
     auto metadata = csr->getCurrentMetadataIfKnown();
@@ -199,7 +199,7 @@ void OpObserverShardingImpl::shardObserveDeleteOp(OperationContext* opCtx,
                                                   const bool inMultiDocumentTransaction) {
     auto* const css = shardingWriteRouter.getCss();
     css->checkShardVersionOrThrow(opCtx);
-    DatabaseShardingState::assertMatchingDbVersion(opCtx, nss.db());
+    DatabaseShardingState::assertMatchingDbVersion(opCtx, DatabaseName{nss.db()});
 
     auto* const csr = checked_cast<CollectionShardingRuntime*>(css);
     auto metadata = csr->getCurrentMetadataIfKnown();
diff --git a/src/mongo/db/s/op_observer_sharding_test.cpp b/src/mongo/db/s/op_observer_sharding_test.cpp
index 65754edcd71..644627a95b8 100644
--- a/src/mongo/db/s/op_observer_sharding_test.cpp
+++ b/src/mongo/db/s/op_observer_sharding_test.cpp
@@ -70,8 +70,9 @@ protected:
         auto db = databaseHolder->openDb(operationContext(), kTestNss.dbName(), &justCreated);
         auto scopedDss = DatabaseShardingState::assertDbLockedAndAcquireExclusive(
             operationContext(), kTestNss.dbName());
-        scopedDss->setDbInfo(operationContext(),
-                             DatabaseType{kTestNss.dbName().db(), ShardId("this"), dbVersion1});
+        scopedDss->setDbInfo(
+            operationContext(),
+            DatabaseType{kTestNss.dbName().db().toString(), ShardId("this"), dbVersion1});
         ASSERT_TRUE(db);
         ASSERT_TRUE(justCreated);
 
diff --git a/src/mongo/db/s/query_analysis_writer.cpp b/src/mongo/db/s/query_analysis_writer.cpp
index 668910cc2cb..59b3be0002f 100644
--- a/src/mongo/db/s/query_analysis_writer.cpp
+++ b/src/mongo/db/s/query_analysis_writer.cpp
@@ -81,7 +81,7 @@ BSONObj createIndex(OperationContext* opCtx, const NamespaceString& nss, const B
 
     DBDirectClient client(opCtx);
     client.runCommand(
-        nss.db(),
+        DatabaseName{nss.db()},
         BSON("createIndexes" << nss.coll().toString() << "indexes" << BSON_ARRAY(indexSpec)),
         resObj);
 
diff --git a/src/mongo/db/s/query_analysis_writer_test.cpp b/src/mongo/db/s/query_analysis_writer_test.cpp
index d6046d5f3a5..a83a9d52c03 100644
--- a/src/mongo/db/s/query_analysis_writer_test.cpp
+++ b/src/mongo/db/s/query_analysis_writer_test.cpp
@@ -210,7 +210,8 @@ protected:
     void assertTTLIndexExists(const NamespaceString& nss, const std::string& name) const {
         DBDirectClient client(operationContext());
         BSONObj result;
-        client.runCommand(nss.db(), BSON("listIndexes" << nss.coll().toString()), result);
+        client.runCommand(
+            DatabaseName{nss.db()}, BSON("listIndexes" << nss.coll().toString()), result);
 
         auto indexes = result.getObjectField("cursor").getField("firstBatch").Array();
         auto iter = indexes.begin();
diff --git a/src/mongo/db/s/range_deletion_util.cpp b/src/mongo/db/s/range_deletion_util.cpp
index 48d606806e8..fde7c227f23 100644
--- a/src/mongo/db/s/range_deletion_util.cpp
+++ b/src/mongo/db/s/range_deletion_util.cpp
@@ -132,7 +132,7 @@ StatusWith<int> deleteNextBatch(OperationContext* opCtx,
 
     if (serverGlobalParams.moveParanoia) {
         deleteStageParams->removeSaver =
-            std::make_unique<RemoveSaver>("moveChunk", nss.ns(), "cleaning");
+            std::make_unique<RemoveSaver>("moveChunk", nss.ns().toString(), "cleaning");
     }
 
     auto exec =
@@ -261,9 +261,10 @@ ExecutorFuture<void> deleteRangeInBatchesWithExecutor(
     return ExecutorFuture<void>(executor).then([=] {
         return withTemporaryOperationContext(
             [=](OperationContext* opCtx) {
-                return deleteRangeInBatches(opCtx, nss.db(), collectionUuid, keyPattern, range);
+                return deleteRangeInBatches(
+                    opCtx, DatabaseName{nss.db()}, collectionUuid, keyPattern, range);
             },
-            nss.db(),
+            DatabaseName{nss.db()},
             collectionUuid);
     });
 }
@@ -291,7 +292,7 @@ ExecutorFuture<void> waitForDeletionsToMajorityReplicate(
                 .waitUntilMajority(clientOpTime, CancellationToken::uncancelable())
                 .thenRunOn(executor);
         },
-        nss.db(),
+        DatabaseName{nss.db()},
         collectionUuid);
 }
 
@@ -545,7 +546,7 @@ SharedSemiFuture<void> removeDocumentsInRange(
                     [&](OperationContext* opCtx) {
                         removePersistentRangeDeletionTask(opCtx, collectionUuid, range);
                     },
-                    nss.db(),
+                    DatabaseName{nss.db()},
                     collectionUuid);
             } catch (const DBException& e) {
                 LOGV2_ERROR(23770,
diff --git a/src/mongo/db/s/rename_collection_coordinator.cpp b/src/mongo/db/s/rename_collection_coordinator.cpp
index 8610f11aa14..38c63f3b14c 100644
--- a/src/mongo/db/s/rename_collection_coordinator.cpp
+++ b/src/mongo/db/s/rename_collection_coordinator.cpp
@@ -360,7 +360,7 @@ ExecutorFuture<void> RenameCollectionCoordinator::_runImpl(
                 // - Locally rename source to target
                 ShardsvrRenameCollectionParticipant renameCollParticipantRequest(
                     fromNss, _doc.getSourceUUID().value());
-                renameCollParticipantRequest.setDbName(fromNss.db());
+                renameCollParticipantRequest.setDbName(DatabaseName{fromNss.db()});
                 renameCollParticipantRequest.setTargetUUID(_doc.getTargetUUID());
                 renameCollParticipantRequest.setRenameCollectionRequest(_request);
                 const auto cmdObj = CommandHelpers::appendMajorityWriteConcern(
@@ -451,7 +451,7 @@ ExecutorFuture<void> RenameCollectionCoordinator::_runImpl(
                 // - Unblock CRUD on participants for both source and destination collections
                 ShardsvrRenameCollectionUnblockParticipant unblockParticipantRequest(
                     fromNss, _doc.getSourceUUID().value());
-                unblockParticipantRequest.setDbName(fromNss.db());
+                unblockParticipantRequest.setDbName(DatabaseName{fromNss.db()});
                 unblockParticipantRequest.setRenameCollectionRequest(_request);
                 auto const cmdObj = CommandHelpers::appendMajorityWriteConcern(
                     unblockParticipantRequest.toBSON({}));
diff --git a/src/mongo/db/s/reshard_collection_coordinator.cpp b/src/mongo/db/s/reshard_collection_coordinator.cpp
index 8f59b884955..064789b14f3 100644
--- a/src/mongo/db/s/reshard_collection_coordinator.cpp
+++ b/src/mongo/db/s/reshard_collection_coordinator.cpp
@@ -159,7 +159,7 @@ ExecutorFuture<void> ReshardCollectionCoordinator::_runImpl(
                 _updateStateDocument(opCtx, std::move(newDoc));
 
                 ConfigsvrReshardCollection configsvrReshardCollection(nss(), _doc.getKey());
-                configsvrReshardCollection.setDbName(nss().db());
+                configsvrReshardCollection.setDbName(DatabaseName{nss().db()});
                 configsvrReshardCollection.setUnique(_doc.getUnique());
                 configsvrReshardCollection.setCollation(_doc.getCollation());
                 configsvrReshardCollection.set_presetReshardedChunks(
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_commit_monitor.cpp b/src/mongo/db/s/resharding/resharding_coordinator_commit_monitor.cpp
index 6cc7f93abad..68f640d13b6 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_commit_monitor.cpp
+++ b/src/mongo/db/s/resharding/resharding_coordinator_commit_monitor.cpp
@@ -61,7 +61,7 @@ MONGO_FAIL_POINT_DEFINE(hangBeforeQueryingRecipients);
 
 BSONObj makeCommandObj(const NamespaceString& ns) {
     auto command = _shardsvrReshardingOperationTime(ns);
-    command.setDbName(DatabaseName(ns.tenantId(), "admin"));
+    command.setDbName(DatabaseName(ns.tenantId(), DatabaseName::kAdmin.db()));
     return command.toBSON({});
 }
 
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_service.cpp b/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
index 2358d4b00a6..75b1b591fff 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
+++ b/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
@@ -697,7 +697,7 @@ void executeMetadataChangesInTxn(
 BSONObj makeFlushRoutingTableCacheUpdatesCmd(const NamespaceString& nss) {
     auto cmd = FlushRoutingTableCacheUpdatesWithWriteConcern(nss);
     cmd.setSyncFromConfig(true);
-    cmd.setDbName(nss.db());
+    cmd.setDbName(DatabaseName{nss.db()});
     return cmd.toBSON(
         BSON(WriteConcernOptions::kWriteConcernField << kMajorityWriteConcern.toBSON()));
 }
@@ -789,7 +789,8 @@ void writeDecisionPersistedState(OperationContext* opCtx,
                                                         txnNumber);
 
             // Delete all of the config.tags entries for the user collection namespace.
-            const auto removeTagsQuery = BSON(TagsType::ns(coordinatorDoc.getSourceNss().ns()));
+            const auto removeTagsQuery =
+                BSON(TagsType::ns(coordinatorDoc.getSourceNss().ns().toString()));
             removeTagsDocs(opCtx, removeTagsQuery);
 
             // Update all of the config.tags entries for the temporary resharding namespace
@@ -803,11 +804,11 @@ void updateTagsDocsForTempNss(OperationContext* opCtx,
     auto hint = BSON("ns" << 1 << "min" << 1);
     auto tagsRequest = BatchedCommandRequest::buildUpdateOp(
         TagsType::ConfigNS,
-        BSON(TagsType::ns(coordinatorDoc.getTempReshardingNss().ns())),    // query
-        BSON("$set" << BSON("ns" << coordinatorDoc.getSourceNss().ns())),  // update
-        false,                                                             // upsert
-        true,                                                              // multi
-        hint                                                               // hint
+        BSON(TagsType::ns(coordinatorDoc.getTempReshardingNss().ns().toString())),  // query
+        BSON("$set" << BSON("ns" << coordinatorDoc.getSourceNss().ns())),           // update
+        false,                                                                      // upsert
+        true,                                                                       // multi
+        hint                                                                        // hint
     );
 
     // Update the 'ns' field to be the original collection namespace for all tags documents that
@@ -861,7 +862,8 @@ void writeParticipantShardsAndTempCollInfo(
     std::vector<ChunkType> initialChunks,
     std::vector<BSONObj> zones,
     boost::optional<CollectionIndexes> indexVersion) {
-    const auto tagsQuery = BSON(TagsType::ns(updatedCoordinatorDoc.getTempReshardingNss().ns()));
+    const auto tagsQuery =
+        BSON(TagsType::ns(updatedCoordinatorDoc.getTempReshardingNss().ns().toString()));
 
     removeChunkAndTagsDocs(opCtx, tagsQuery, updatedCoordinatorDoc.getReshardingUUID());
     insertChunkAndTagDocsForTempNss(opCtx, initialChunks, zones);
@@ -944,7 +946,8 @@ void removeCoordinatorDocAndReshardingFields(OperationContext* opCtx,
     updatedCoordinatorDoc.setState(CoordinatorStateEnum::kDone);
     emplaceTruncatedAbortReasonIfExists(updatedCoordinatorDoc, abortReason);
 
-    const auto tagsQuery = BSON(TagsType::ns(coordinatorDoc.getTempReshardingNss().ns()));
+    const auto tagsQuery =
+        BSON(TagsType::ns(coordinatorDoc.getTempReshardingNss().ns().toString()));
     // Once the decision has been persisted, the coordinator would have modified the
     // config.chunks and config.collections entry. This means that the UUID of the
     // non-temp collection is now the UUID of what was previously the UUID of the temp
diff --git a/src/mongo/db/s/resharding/resharding_manual_cleanup.cpp b/src/mongo/db/s/resharding/resharding_manual_cleanup.cpp
index fad84d1a4e8..8e0caf72733 100644
--- a/src/mongo/db/s/resharding/resharding_manual_cleanup.cpp
+++ b/src/mongo/db/s/resharding/resharding_manual_cleanup.cpp
@@ -239,7 +239,7 @@ bool ReshardingCoordinatorCleaner::_checkExistsTempReshardingCollection(
 void ReshardingCoordinatorCleaner::_dropTemporaryReshardingCollection(
     OperationContext* opCtx, const NamespaceString& tempReshardingNss) {
     ShardsvrDropCollection dropCollectionCommand(tempReshardingNss);
-    dropCollectionCommand.setDbName(tempReshardingNss.db());
+    dropCollectionCommand.setDbName(DatabaseName{tempReshardingNss.db()});
 
     const auto dbInfo = uassertStatusOK(
         Grid::get(opCtx)->catalogCache()->getDatabase(opCtx, tempReshardingNss.db()));
diff --git a/src/mongo/db/s/sessions_collection_config_server.cpp b/src/mongo/db/s/sessions_collection_config_server.cpp
index 8aa967d33cb..86ad7cfe44c 100644
--- a/src/mongo/db/s/sessions_collection_config_server.cpp
+++ b/src/mongo/db/s/sessions_collection_config_server.cpp
@@ -64,7 +64,7 @@ void SessionsCollectionConfigServer::_shardCollectionIfNeeded(OperationContext*
     CreateCollectionRequest requestParamsObj;
     requestParamsObj.setShardKey(BSON("_id" << 1));
     shardsvrCollRequest.setCreateCollectionRequest(std::move(requestParamsObj));
-    shardsvrCollRequest.setDbName(NamespaceString::kLogicalSessionsNamespace.db());
+    shardsvrCollRequest.setDbName(DatabaseName{NamespaceString::kLogicalSessionsNamespace.db()});
 
     cluster::createCollection(opCtx, shardsvrCollRequest);
 }
diff --git a/src/mongo/db/s/shard_filtering_metadata_refresh.cpp b/src/mongo/db/s/shard_filtering_metadata_refresh.cpp
index 17474c445dd..ecc4832caa3 100644
--- a/src/mongo/db/s/shard_filtering_metadata_refresh.cpp
+++ b/src/mongo/db/s/shard_filtering_metadata_refresh.cpp
@@ -241,11 +241,12 @@ void onDbVersionMismatch(OperationContext* opCtx,
 
         {
             boost::optional<Lock::DBLock> dbLock;
-            dbLock.emplace(opCtx, dbName, MODE_IS);
+            dbLock.emplace(opCtx, DatabaseName{dbName}, MODE_IS);
 
             if (receivedDbVersion) {
-                auto scopedDss = boost::make_optional(
-                    DatabaseShardingState::assertDbLockedAndAcquireShared(opCtx, dbName));
+                auto scopedDss =
+                    boost::make_optional(DatabaseShardingState::assertDbLockedAndAcquireShared(
+                        opCtx, DatabaseName{dbName}));
 
                 if (joinDbVersionOperation(opCtx, &dbLock, &scopedDss)) {
                     // Waited for another thread to exit from the critical section or to complete an
@@ -270,8 +271,9 @@ void onDbVersionMismatch(OperationContext* opCtx,
                 return;
             }
 
-            auto scopedDss = boost::make_optional(
-                DatabaseShardingState::assertDbLockedAndAcquireExclusive(opCtx, dbName));
+            auto scopedDss =
+                boost::make_optional(DatabaseShardingState::assertDbLockedAndAcquireExclusive(
+                    opCtx, DatabaseName{dbName}));
 
             if (joinDbVersionOperation(opCtx, &dbLock, &scopedDss)) {
                 // Waited for another thread to exit from the critical section or to complete an
@@ -288,7 +290,7 @@ void onDbVersionMismatch(OperationContext* opCtx,
             CancellationToken cancellationToken = cancellationSource.token();
             (*scopedDss)
                 ->setDbMetadataRefreshFuture(
-                    recoverRefreshDbVersion(opCtx, dbName, cancellationToken),
+                    recoverRefreshDbVersion(opCtx, DatabaseName{dbName}, cancellationToken),
                     std::move(cancellationSource));
             dbMetadataRefreshFuture = (*scopedDss)->getDbMetadataRefreshFuture();
         }
diff --git a/src/mongo/db/s/sharding_catalog_client_aggregations_test.cpp b/src/mongo/db/s/sharding_catalog_client_aggregations_test.cpp
index 23d3a49da25..c3ae0750871 100644
--- a/src/mongo/db/s/sharding_catalog_client_aggregations_test.cpp
+++ b/src/mongo/db/s/sharding_catalog_client_aggregations_test.cpp
@@ -433,10 +433,12 @@ TEST_F(CatalogClientAggregationsTest, GetShardsThatOwnDataForCollAtClusterTime_W
     auto opCtx = operationContext();
     PlacementDescriptor _startFcvMarker = {
         Timestamp(1, 0),
-        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns(),
+        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns().toString(),
         {"shard1", "shard2", "shard3", "shard4", "shard5"}};
     PlacementDescriptor _endFcvMarker = {
-        Timestamp(3, 0), NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns(), {}};
+        Timestamp(3, 0),
+        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns().toString(),
+        {}};
 
     // initialization
     setupConfigPlacementHistory(
@@ -680,10 +682,12 @@ TEST_F(CatalogClientAggregationsTest, GetShardsThatOwnDataForDbAtClusterTime_Wit
     auto opCtx = operationContext();
     PlacementDescriptor _startFcvMarker = {
         Timestamp(1, 0),
-        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns(),
+        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns().toString(),
         {"shard1", "shard2", "shard3", "shard4", "shard5"}};
     PlacementDescriptor _endFcvMarker = {
-        Timestamp(3, 0), NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns(), {}};
+        Timestamp(3, 0),
+        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns().toString(),
+        {}};
 
     // initialization
     setupConfigPlacementHistory(
@@ -889,10 +893,12 @@ TEST_F(CatalogClientAggregationsTest, GetShardsThatOwnDataAtClusterTime_WithMark
     auto opCtx = operationContext();
     PlacementDescriptor _startFcvMarker = {
         Timestamp(1, 0),
-        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns(),
+        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns().toString(),
         {"shard1", "shard2", "shard3", "shard4"}};
     PlacementDescriptor _endFcvMarker = {
-        Timestamp(3, 0), NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns(), {}};
+        Timestamp(3, 0),
+        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns().toString(),
+        {}};
 
     // initialization
     setupConfigPlacementHistory(
@@ -1194,10 +1200,12 @@ TEST_F(CatalogClientAggregationsTest, GetShardsThatOwnDataAtClusterTime_CleanUp_
     auto opCtx = operationContext();
     PlacementDescriptor startFcvMarker = {
         Timestamp(1, 0),
-        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns(),
+        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns().toString(),
         {"shard1", "shard2", "shard3", "shard4"}};
     PlacementDescriptor endFcvMarker = {
-        Timestamp(3, 0), NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns(), {}};
+        Timestamp(3, 0),
+        NamespaceString::kConfigsvrPlacementHistoryFcvMarkerNamespace.ns().toString(),
+        {}};
 
     // initialization
     setupConfigPlacementHistory(
diff --git a/src/mongo/db/s/sharding_ddl_coordinator.cpp b/src/mongo/db/s/sharding_ddl_coordinator.cpp
index 0606cba0993..dc746339fbf 100644
--- a/src/mongo/db/s/sharding_ddl_coordinator.cpp
+++ b/src/mongo/db/s/sharding_ddl_coordinator.cpp
@@ -289,7 +289,8 @@ SemiFuture<void> ShardingDDLCoordinator::run(std::shared_ptr<executor::ScopedTas
                     metadata().getDatabaseVersion() /* databaseVersion */);
 
                 // Check under the dbLock if this is still the primary shard for the database
-                DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, originalNss().db());
+                DatabaseShardingState::assertIsPrimaryShardForDb(opCtx,
+                                                                 DatabaseName{originalNss().db()});
             };
         })
         .then([this, executor, token, anchor = shared_from_this()] {
diff --git a/src/mongo/db/s/sharding_ddl_coordinator_service.cpp b/src/mongo/db/s/sharding_ddl_coordinator_service.cpp
index 7ea139345a3..3cd9fc18681 100644
--- a/src/mongo/db/s/sharding_ddl_coordinator_service.cpp
+++ b/src/mongo/db/s/sharding_ddl_coordinator_service.cpp
@@ -278,7 +278,7 @@ ShardingDDLCoordinatorService::getOrCreateInstance(OperationContext* opCtx, BSON
         uassert(ErrorCodes::IllegalOperation,
                 "Request sent without attaching database version",
                 clientDbVersion);
-        DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, nss.db());
+        DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, DatabaseName{nss.db()});
         coorMetadata.setDatabaseVersion(clientDbVersion);
     }
 
diff --git a/src/mongo/db/s/sharding_ddl_util.cpp b/src/mongo/db/s/sharding_ddl_util.cpp
index 9560059c026..a7e01084de5 100644
--- a/src/mongo/db/s/sharding_ddl_util.cpp
+++ b/src/mongo/db/s/sharding_ddl_util.cpp
@@ -111,8 +111,8 @@ void updateTags(OperationContext* opCtx,
                 const NamespaceString& fromNss,
                 const NamespaceString& toNss,
                 const WriteConcernOptions& writeConcern) {
-    const auto query = BSON(TagsType::ns(fromNss.ns()));
-    const auto update = BSON("$set" << BSON(TagsType::ns(toNss.ns())));
+    const auto query = BSON(TagsType::ns(fromNss.ns().toString()));
+    const auto update = BSON("$set" << BSON(TagsType::ns(toNss.ns().toString())));
 
     BatchedCommandRequest request([&] {
         write_ops::UpdateCommandRequest updateOp(TagsType::ConfigNS);
@@ -474,7 +474,7 @@ void removeTagsMetadataFromConfig_notIdempotent(OperationContext* opCtx,
                                                 const NamespaceString& nss,
                                                 const WriteConcernOptions& writeConcern) {
     // Remove config.tags entries
-    const auto query = BSON(TagsType::ns(nss.ns()));
+    const auto query = BSON(TagsType::ns(nss.ns().toString()));
     const auto hint = BSON(TagsType::ns() << 1 << TagsType::min() << 1);
 
     BatchedCommandRequest request([&] {
diff --git a/src/mongo/db/s/sharding_ddl_util_test.cpp b/src/mongo/db/s/sharding_ddl_util_test.cpp
index ee4c94640e6..14866dfb958 100644
--- a/src/mongo/db/s/sharding_ddl_util_test.cpp
+++ b/src/mongo/db/s/sharding_ddl_util_test.cpp
@@ -350,7 +350,7 @@ TEST_F(ShardingDDLUtilTest, RenamePreconditionsTargetNamespaceIsTooLong) {
 
     // Check that an exception is thrown if the namespace of the target collection is too long
     const NamespaceString tooLongNss =
-        NamespaceString::createNamespaceString_forTest(longEnoughNss.ns() + 'x');
+        NamespaceString::createNamespaceString_forTest(longEnoughNss.ns().toString() + 'x');
     ASSERT_THROWS_CODE(sharding_ddl_util::checkRenamePreconditions(
                            opCtx, true /* sourceIsSharded */, tooLongNss, false /* dropTarget */),
                        AssertionException,
diff --git a/src/mongo/db/s/sharding_state_recovery.cpp b/src/mongo/db/s/sharding_state_recovery.cpp
index 0a73b4a91a3..8ec7f8b12fb 100644
--- a/src/mongo/db/s/sharding_state_recovery.cpp
+++ b/src/mongo/db/s/sharding_state_recovery.cpp
@@ -147,7 +147,8 @@ Status modifyRecoveryDocument(OperationContext* opCtx,
     try {
         // Use boost::optional so we can release the locks early
         boost::optional<AutoGetDb> autoGetDb;
-        autoGetDb.emplace(opCtx, NamespaceString::kServerConfigurationNamespace.db(), MODE_X);
+        autoGetDb.emplace(
+            opCtx, DatabaseName{NamespaceString::kServerConfigurationNamespace.db()}, MODE_X);
 
         const auto configOpTime = [&]() {
             const auto vcTime = VectorClock::get(opCtx)->getTime();
diff --git a/src/mongo/db/s/sharding_util.cpp b/src/mongo/db/s/sharding_util.cpp
index 4cf80f20341..395e1bd463c 100644
--- a/src/mongo/db/s/sharding_util.cpp
+++ b/src/mongo/db/s/sharding_util.cpp
@@ -58,7 +58,7 @@ void tellShardsToRefreshCollection(OperationContext* opCtx,
                                    const std::shared_ptr<executor::TaskExecutor>& executor) {
     auto cmd = FlushRoutingTableCacheUpdatesWithWriteConcern(nss);
     cmd.setSyncFromConfig(true);
-    cmd.setDbName(nss.db());
+    cmd.setDbName(DatabaseName{nss.db()});
     auto cmdObj = CommandHelpers::appendMajorityWriteConcern(cmd.toBSON({}));
     sendCommandToShards(opCtx, DatabaseName::kAdmin.db(), cmdObj, shardIds, executor);
 }
diff --git a/src/mongo/db/s/shardsvr_check_metadata_consistency_command.cpp b/src/mongo/db/s/shardsvr_check_metadata_consistency_command.cpp
index cb96382be0f..673a7368bc7 100644
--- a/src/mongo/db/s/shardsvr_check_metadata_consistency_command.cpp
+++ b/src/mongo/db/s/shardsvr_check_metadata_consistency_command.cpp
@@ -202,7 +202,7 @@ public:
             const auto dbDDLLock = ddlLockManager->lock(
                 opCtx, nss.db(), kLockReason, DDLLockManager::kDefaultLockTimeout);
 
-            DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, nss.dbName());
+            DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, DatabaseName{nss.db()});
 
             return establishCursors(opCtx,
                                     Grid::get(opCtx)->getExecutorPool()->getFixedExecutor(),
diff --git a/src/mongo/db/s/shardsvr_drop_indexes_command.cpp b/src/mongo/db/s/shardsvr_drop_indexes_command.cpp
index 0a552d680a0..237ab96fa0f 100644
--- a/src/mongo/db/s/shardsvr_drop_indexes_command.cpp
+++ b/src/mongo/db/s/shardsvr_drop_indexes_command.cpp
@@ -160,7 +160,7 @@ ShardsvrDropIndexesCommand::Invocation::Response ShardsvrDropIndexesCommand::Inv
     auto dbDDLLock = ddlLockManager->lock(opCtx, ns().db(), lockReason, lockTimeout);
 
     // Check under the dbLock if this is still the primary shard for the database
-    DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, ns().db());
+    DatabaseShardingState::assertIsPrimaryShardForDb(opCtx, DatabaseName{ns().db()});
 
     auto resolvedNs = ns();
     auto dropIdxBSON = dropIdxCmd.toBSON({});
diff --git a/src/mongo/db/service_entry_point_common.cpp b/src/mongo/db/service_entry_point_common.cpp
index 3d5e515301f..3fea51ec200 100644
--- a/src/mongo/db/service_entry_point_common.cpp
+++ b/src/mongo/db/service_entry_point_common.cpp
@@ -1270,7 +1270,7 @@ void RunCommandImpl::_epilogue() {
                                             _ecd->getLastOpBeforeRun(),
                                             _ecd->getLastOpAfterRun());
         appendAdditionalParticipants(
-            opCtx, &body, command->getName(), _ecd->getInvocation()->ns().ns());
+            opCtx, &body, command->getName(), _ecd->getInvocation()->ns().ns().toString());
     }
 
     auto commandBodyBob = replyBuilder->getBodyBuilder();
@@ -1945,7 +1945,7 @@ void ExecCommandDatabase::_handleFailure(Status status) {
                                         getLastOpBeforeRun(),
                                         getLastOpAfterRun());
     appendAdditionalParticipants(
-        opCtx, &_extraFieldsBuilder, command->getName(), _execContext->nsString().ns());
+        opCtx, &_extraFieldsBuilder, command->getName(), _execContext->nsString().ns().toString());
 
     BSONObjBuilder metadataBob;
     behaviors.appendReplyMetadata(opCtx, request, &metadataBob);
diff --git a/src/mongo/db/shard_role.cpp b/src/mongo/db/shard_role.cpp
index 6bdefaf59ae..88933f3bff9 100644
--- a/src/mongo/db/shard_role.cpp
+++ b/src/mongo/db/shard_role.cpp
@@ -204,7 +204,8 @@ void checkPlacementVersion(OperationContext* opCtx,
                            const PlacementConcern& placementConcern) {
     const auto& receivedDbVersion = placementConcern.dbVersion;
     if (receivedDbVersion) {
-        DatabaseShardingState::assertMatchingDbVersion(opCtx, nss.db(), *receivedDbVersion);
+        DatabaseShardingState::assertMatchingDbVersion(
+            opCtx, DatabaseName{nss.db()}, *receivedDbVersion);
     }
 
     const auto& receivedShardVersion = placementConcern.shardVersion;
diff --git a/src/mongo/db/shard_role_test.cpp b/src/mongo/db/shard_role_test.cpp
index 6c0993dae23..f630827261c 100644
--- a/src/mongo/db/shard_role_test.cpp
+++ b/src/mongo/db/shard_role_test.cpp
@@ -64,7 +64,7 @@ void installDatabaseMetadata(OperationContext* opCtx,
                              const DatabaseVersion& dbVersion) {
     AutoGetDb autoDb(opCtx, dbName, MODE_X, {}, {});
     auto scopedDss = DatabaseShardingState::assertDbLockedAndAcquireExclusive(opCtx, dbName);
-    scopedDss->setDbInfo(opCtx, {dbName.db(), ShardId("this"), dbVersion});
+    scopedDss->setDbInfo(opCtx, {dbName.db().toString(), ShardId("this"), dbVersion});
 }
 
 void installUnshardedCollectionMetadata(OperationContext* opCtx, const NamespaceString& nss) {
@@ -838,18 +838,18 @@ TEST_F(ShardRoleTest, YieldAndRestoreAcquisitionWithLocks) {
                                                },
                                                MODE_IX);
 
-    ASSERT_TRUE(opCtx()->lockState()->isDbLockedForMode(nss.db(), MODE_IX));
+    ASSERT_TRUE(opCtx()->lockState()->isDbLockedForMode(DatabaseName{nss.db()}, MODE_IX));
     ASSERT_TRUE(opCtx()->lockState()->isCollectionLockedForMode(nss, MODE_IX));
 
     // Yield the resources
     auto yieldedTransactionResources = yieldTransactionResourcesFromOperationContext(opCtx());
     ASSERT(yieldedTransactionResources);
-    ASSERT_FALSE(opCtx()->lockState()->isDbLockedForMode(nss.db(), MODE_IX));
+    ASSERT_FALSE(opCtx()->lockState()->isDbLockedForMode(DatabaseName{nss.db()}, MODE_IX));
     ASSERT_FALSE(opCtx()->lockState()->isCollectionLockedForMode(nss, MODE_IX));
 
     // Restore the resources
     restoreTransactionResourcesToOperationContext(opCtx(), std::move(*yieldedTransactionResources));
-    ASSERT_TRUE(opCtx()->lockState()->isDbLockedForMode(nss.db(), MODE_IX));
+    ASSERT_TRUE(opCtx()->lockState()->isDbLockedForMode(DatabaseName{nss.db()}, MODE_IX));
     ASSERT_TRUE(opCtx()->lockState()->isCollectionLockedForMode(nss, MODE_IX));
 }
 
@@ -898,7 +898,7 @@ TEST_F(ShardRoleTest, RestoreForWriteFailsIfPlacementConcernNoLongerMet) {
                                  ASSERT_FALSE(exInfo->getCriticalSectionSignal().is_initialized());
                              });
 
-    ASSERT_FALSE(opCtx()->lockState()->isDbLockedForMode(nss.db(), MODE_IX));
+    ASSERT_FALSE(opCtx()->lockState()->isDbLockedForMode(DatabaseName{nss.db()}, MODE_IX));
     ASSERT_FALSE(opCtx()->lockState()->isCollectionLockedForMode(nss, MODE_IX));
 }
 
diff --git a/src/mongo/db/stats/fill_locker_info_test.cpp b/src/mongo/db/stats/fill_locker_info_test.cpp
index 3bc23346349..2ab5714f6e3 100644
--- a/src/mongo/db/stats/fill_locker_info_test.cpp
+++ b/src/mongo/db/stats/fill_locker_info_test.cpp
@@ -92,7 +92,7 @@ DEATH_TEST(FillLockerInfo, ShouldFailIfLocksAreNotSortedAppropriately, "Invarian
 }
 
 TEST(FillLockerInfo, DoesReportLocksHeld) {
-    const ResourceId dbId(RESOURCE_DATABASE, "TestDB"_sd);
+    const ResourceId dbId(RESOURCE_DATABASE, DatabaseName{"TestDB"_sd});
     LockerInfo info;
     info.locks = {OneLock{resourceIdGlobal, MODE_IX}, OneLock{dbId, MODE_IX}};
 
@@ -109,8 +109,8 @@ TEST(FillLockerInfo, DoesReportLocksHeld) {
 }
 
 TEST(FillLockerInfo, ShouldReportMaxTypeHeldForResourceType) {
-    const ResourceId firstDbId(RESOURCE_DATABASE, "FirstDB"_sd);
-    const ResourceId secondDbId(RESOURCE_DATABASE, "SecondDB"_sd);
+    const ResourceId firstDbId(RESOURCE_DATABASE, DatabaseName{"FirstDB"_sd});
+    const ResourceId secondDbId(RESOURCE_DATABASE, DatabaseName{"SecondDB"_sd});
     LockerInfo info;
     info.locks = {OneLock{resourceIdGlobal, MODE_IX},
                   OneLock{firstDbId, MODE_IX},
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_record_store.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_record_store.cpp
index a47fa2aecb1..a7f6ec63ffc 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_record_store.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_record_store.cpp
@@ -600,7 +600,7 @@ std::string WiredTigerRecordStore::ns(OperationContext* opCtx) const {
     if (!nss)
         return "";
 
-    return nss->ns();
+    return nss->ns().toString();
 }
 
 void WiredTigerRecordStore::checkSize(OperationContext* opCtx) {
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_record_store_test_harness.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_record_store_test_harness.cpp
index 742c43b6262..db643dc6f13 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_record_store_test_harness.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_record_store_test_harness.cpp
@@ -116,7 +116,7 @@ std::unique_ptr<RecordStore> WiredTigerHarnessHelper::newOplogRecordStore() {
 std::unique_ptr<RecordStore> WiredTigerHarnessHelper::newOplogRecordStoreNoInit() {
     ServiceContext::UniqueOperationContext opCtx(newOperationContext());
     WiredTigerRecoveryUnit* ru = checked_cast<WiredTigerRecoveryUnit*>(opCtx->recoveryUnit());
-    std::string ident = NamespaceString::kRsOplogNamespace.ns();
+    std::string ident = NamespaceString::kRsOplogNamespace.ns().toString();
     std::string uri = WiredTigerKVEngine::kTableUriPrefix + ident;
 
     CollectionOptions options;
diff --git a/src/mongo/db/ttl.cpp b/src/mongo/db/ttl.cpp
index 98e7d5fe662..c14bd33b50b 100644
--- a/src/mongo/db/ttl.cpp
+++ b/src/mongo/db/ttl.cpp
@@ -898,8 +898,8 @@ void TTLMonitor::onStepUp(OperationContext* opCtx) {
 
                 // processCollModCommand() will acquire MODE_X access to the collection.
                 BSONObjBuilder builder;
-                uassertStatusOK(
-                    processCollModCommand(opCtx, {nss->db(), uuid}, collModCmd, &builder));
+                uassertStatusOK(processCollModCommand(
+                    opCtx, {DatabaseName{nss->db()}, uuid}, collModCmd, &builder));
                 auto result = builder.obj();
                 LOGV2(
                     6847701,
diff --git a/src/mongo/db/views/view_catalog_test.cpp b/src/mongo/db/views/view_catalog_test.cpp
index 1b1232dba64..967e0dc98cd 100644
--- a/src/mongo/db/views/view_catalog_test.cpp
+++ b/src/mongo/db/views/view_catalog_test.cpp
@@ -584,7 +584,7 @@ TEST_F(ViewCatalogFixture, LookupRIDAfterDropRollback) {
         ASSERT_OK(createView(operationContext(), viewName, viewOn, emptyPipeline, emptyCollation));
         wunit.commit();
         ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID).value(),
-                  viewName.ns());
+                  viewName.ns().toString());
     }
 
     {
@@ -600,7 +600,7 @@ TEST_F(ViewCatalogFixture, LookupRIDAfterDropRollback) {
         // Do not commit, rollback.
     }
     // Make sure drop was rolled back and view is still in catalog.
-    ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID), viewName.ns());
+    ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID), viewName.ns().toString());
 }
 
 TEST_F(ViewCatalogFixture, LookupRIDAfterModify) {
@@ -612,7 +612,7 @@ TEST_F(ViewCatalogFixture, LookupRIDAfterModify) {
                    NamespaceString::createNamespaceString_forTest(boost::none, "db.view"));
     ASSERT_OK(createView(operationContext(), viewName, viewOn, emptyPipeline, emptyCollation));
     ASSERT_OK(modifyView(operationContext(), viewName, viewOn, emptyPipeline));
-    ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID), viewName.ns());
+    ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID), viewName.ns().toString());
 }
 
 TEST_F(ViewCatalogFixture, LookupRIDAfterModifyRollback) {
@@ -626,7 +626,8 @@ TEST_F(ViewCatalogFixture, LookupRIDAfterModifyRollback) {
         WriteUnitOfWork wunit(operationContext());
         ASSERT_OK(createView(operationContext(), viewName, viewOn, emptyPipeline, emptyCollation));
         wunit.commit();
-        ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID), viewName.ns());
+        ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID),
+                  viewName.ns().toString());
     }
 
     {
@@ -643,11 +644,12 @@ TEST_F(ViewCatalogFixture, LookupRIDAfterModifyRollback) {
                                            viewOn,
                                            emptyPipeline,
                                            view_catalog_helpers::validatePipeline));
-        ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID), viewName.ns());
+        ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID),
+                  viewName.ns().toString());
         // Do not commit, rollback.
     }
     // Make sure view resource is still available after rollback.
-    ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID), viewName.ns());
+    ASSERT_EQ(ResourceCatalog::get(getServiceContext()).name(resourceID), viewName.ns().toString());
 }
 
 TEST_F(ViewCatalogFixture, CreateViewThenDropAndLookup) {
diff --git a/src/mongo/db/views/view_definition_test.cpp b/src/mongo/db/views/view_definition_test.cpp
index e6f71d33efe..19010030237 100644
--- a/src/mongo/db/views/view_definition_test.cpp
+++ b/src/mongo/db/views/view_definition_test.cpp
@@ -118,7 +118,8 @@ TEST(ViewDefinitionTest, SetViewOnSucceedsIfNewViewOnIsInSameDatabaseAsView) {
 }
 
 TEST(ViewDefinitionTest, SetPipelineSucceedsOnValidArrayBSONElement) {
-    ViewDefinition viewDef(viewNss.db(), viewNss.coll(), backingNss.coll(), BSONObj(), nullptr);
+    ViewDefinition viewDef(
+        DatabaseName{viewNss.db()}, viewNss.coll(), backingNss.coll(), BSONObj(), nullptr);
     ASSERT(viewDef.pipeline().empty());
 
     BSONObj matchStage = BSON("match" << BSON("x" << 9));
diff --git a/src/mongo/dbtests/clienttests.cpp b/src/mongo/dbtests/clienttests.cpp
index 262a0010a5a..c65ddc2885a 100644
--- a/src/mongo/dbtests/clienttests.cpp
+++ b/src/mongo/dbtests/clienttests.cpp
@@ -66,8 +66,8 @@ public:
         return _nss;
     }
 
-    const std::string& ns() {
-        return _nss.toString();
+    StringData ns() {
+        return _nss.ns();
     }
 
     const NamespaceString _nss;
diff --git a/src/mongo/dbtests/dbtests.cpp b/src/mongo/dbtests/dbtests.cpp
index 97ae6f11d6d..f232e1e1274 100644
--- a/src/mongo/dbtests/dbtests.cpp
+++ b/src/mongo/dbtests/dbtests.cpp
@@ -181,7 +181,7 @@ Status createIndexFromSpec(OperationContext* opCtx, StringData ns, const BSONObj
 WriteContextForTests::WriteContextForTests(OperationContext* opCtx, StringData ns)
     : _opCtx(opCtx), _nss(ns) {
     // Lock the database and collection
-    _autoDb.emplace(opCtx, _nss.db(), MODE_IX);
+    _autoDb.emplace(opCtx, DatabaseName{_nss.db()}, MODE_IX);
     _collLock.emplace(opCtx, _nss, MODE_IX);
 
     const bool doShardVersionCheck = false;
diff --git a/src/mongo/dbtests/mock/mock_remote_db_server.cpp b/src/mongo/dbtests/mock/mock_remote_db_server.cpp
index 9c6e880edee..5ad274084d6 100644
--- a/src/mongo/dbtests/mock/mock_remote_db_server.cpp
+++ b/src/mongo/dbtests/mock/mock_remote_db_server.cpp
@@ -127,22 +127,23 @@ void MockRemoteDBServer::setCommandReply(const string& cmdName,
 void MockRemoteDBServer::insert(const NamespaceString& nss, BSONObj obj) {
     scoped_spinlock sLock(_lock);
 
-    vector<BSONObj>& mockCollection = _dataMgr[nss.ns()];
+    vector<BSONObj>& mockCollection = _dataMgr[nss.ns().toString()];
     mockCollection.push_back(obj.copy());
 }
 
 void MockRemoteDBServer::remove(const NamespaceString& nss, const BSONObj&) {
     scoped_spinlock sLock(_lock);
-    if (_dataMgr.count(nss.ns()) == 0) {
+    auto ns = nss.ns().toString();
+    if (_dataMgr.count(ns) == 0) {
         return;
     }
 
-    _dataMgr.erase(nss.ns());
+    _dataMgr.erase(ns);
 }
 
-void MockRemoteDBServer::assignCollectionUuid(const std::string& ns, const mongo::UUID& uuid) {
+void MockRemoteDBServer::assignCollectionUuid(StringData ns, const mongo::UUID& uuid) {
     scoped_spinlock sLock(_lock);
-    _uuidToNs[uuid] = ns;
+    _uuidToNs[uuid] = ns.toString();
 }
 
 rpc::UniqueReply MockRemoteDBServer::runCommand(InstanceID id, const OpMsgRequest& request) {
@@ -213,7 +214,7 @@ mongo::BSONArray MockRemoteDBServer::findImpl(InstanceID id,
     scoped_spinlock sLock(_lock);
     _queryCount++;
 
-    auto ns = nsOrUuid.uuid() ? _uuidToNs[*nsOrUuid.uuid()] : nsOrUuid.nss()->ns();
+    auto ns = nsOrUuid.uuid() ? _uuidToNs[*nsOrUuid.uuid()] : nsOrUuid.nss()->ns().toString();
     const vector<BSONObj>& coll = _dataMgr[ns];
     BSONArrayBuilder result;
     for (vector<BSONObj>::const_iterator iter = coll.begin(); iter != coll.end(); ++iter) {
diff --git a/src/mongo/dbtests/mock/mock_remote_db_server.h b/src/mongo/dbtests/mock/mock_remote_db_server.h
index 170d1617d6b..c3f7930b621 100644
--- a/src/mongo/dbtests/mock/mock_remote_db_server.h
+++ b/src/mongo/dbtests/mock/mock_remote_db_server.h
@@ -155,7 +155,7 @@ public:
      * @param ns the namespace to be associated with the uuid.
      * @param uuid the uuid to associate with the namespace.
      */
-    void assignCollectionUuid(const std::string& ns, const mongo::UUID& uuid);
+    void assignCollectionUuid(StringData ns, const mongo::UUID& uuid);
 
     //
     // DBClientBase methods
diff --git a/src/mongo/dbtests/plan_executor_invalidation_test.cpp b/src/mongo/dbtests/plan_executor_invalidation_test.cpp
index 6c552e9e3a4..c84632abaab 100644
--- a/src/mongo/dbtests/plan_executor_invalidation_test.cpp
+++ b/src/mongo/dbtests/plan_executor_invalidation_test.cpp
@@ -129,7 +129,7 @@ public:
         return res;
     }
 
-    bool dropCollection(const std::string& ns) {
+    bool dropCollection(StringData ns) {
         bool res = _client.dropCollection(NamespaceString(ns));
         _refreshCollection();
         return res;
diff --git a/src/mongo/dbtests/query_stage_and.cpp b/src/mongo/dbtests/query_stage_and.cpp
index ce7448a5f10..7dd0fe15bdf 100644
--- a/src/mongo/dbtests/query_stage_and.cpp
+++ b/src/mongo/dbtests/query_stage_and.cpp
@@ -149,8 +149,8 @@ public:
         return BSONObj();
     }
 
-    const char* ns() {
-        return _nss.ns().c_str();
+    StringData ns() {
+        return _nss.ns();
     }
     const NamespaceString& nss() {
         return _nss;
diff --git a/src/mongo/dbtests/querytests.cpp b/src/mongo/dbtests/querytests.cpp
index 091357cf35d..3d358516a0c 100644
--- a/src/mongo/dbtests/querytests.cpp
+++ b/src/mongo/dbtests/querytests.cpp
@@ -53,7 +53,7 @@
 namespace mongo {
 namespace {
 
-void insertOplogDocument(OperationContext* opCtx, Timestamp ts, const char* ns) {
+void insertOplogDocument(OperationContext* opCtx, Timestamp ts, StringData ns) {
     AutoGetCollection coll(opCtx, NamespaceString{ns}, MODE_IX);
     WriteUnitOfWork wuow(opCtx);
     auto doc = BSON("ts" << ts);
@@ -730,7 +730,7 @@ public:
                                     << "oplog.querytests.OplogScanWithGtTimstampPred"),
                                info);
         }
-        const char* ns = _nss.ns().c_str();
+        const auto ns = _nss.ns();
         insertOplogDocument(&_opCtx, Timestamp(1000, 0), ns);
         insertOplogDocument(&_opCtx, Timestamp(1000, 1), ns);
         insertOplogDocument(&_opCtx, Timestamp(1000, 2), ns);
@@ -783,7 +783,7 @@ public:
                                info);
         }
 
-        const char* ns = _nss.ns().c_str();
+        const auto ns = _nss.ns();
         insertOplogDocument(&_opCtx, Timestamp(1000, 0), ns);
         insertOplogDocument(&_opCtx, Timestamp(1000, 1), ns);
         insertOplogDocument(&_opCtx, Timestamp(1000, 2), ns);
@@ -1347,8 +1347,8 @@ public:
         return CursorManager::get(&_opCtx)->numCursors();
     }
 
-    const char* ns() {
-        return _nss.ns().c_str();
+    StringData ns() {
+        return _nss.ns();
     }
     const NamespaceString& nss() {
         return _nss;
diff --git a/src/mongo/dbtests/rollbacktests.cpp b/src/mongo/dbtests/rollbacktests.cpp
index 70aee1d3d1a..95667e062fb 100644
--- a/src/mongo/dbtests/rollbacktests.cpp
+++ b/src/mongo/dbtests/rollbacktests.cpp
@@ -57,7 +57,7 @@ void dropDatabase(OperationContext* opCtx, const NamespaceString& nss) {
     }
 }
 
-bool collectionExists(OperationContext* opCtx, OldClientContext* ctx, const std::string& ns) {
+bool collectionExists(OperationContext* opCtx, OldClientContext* ctx, StringData ns) {
     return (bool)CollectionCatalog::get(opCtx)->lookupCollectionByNamespace(opCtx,
                                                                             NamespaceString(ns));
 }
diff --git a/src/mongo/idl/idl_test.cpp b/src/mongo/idl/idl_test.cpp
index c70ca8adb59..a00c1951796 100644
--- a/src/mongo/idl/idl_test.cpp
+++ b/src/mongo/idl/idl_test.cpp
@@ -2877,7 +2877,7 @@ TEST(IDLCommand, TestIgnore) {
         BasicIgnoredCommand one_new;
         one_new.setField1(3);
         one_new.setField2("five");
-        one_new.setDbName(DatabaseName(boost::none, "admin"));
+        one_new.setDbName(DatabaseName::kAdmin);
         ASSERT_BSONOBJ_EQ(testDocWithDB, serializeCmd(one_new));
     }
 }
diff --git a/src/mongo/s/catalog/sharding_catalog_client_impl.cpp b/src/mongo/s/catalog/sharding_catalog_client_impl.cpp
index cc7349c4cf7..fdb924af0e6 100644
--- a/src/mongo/s/catalog/sharding_catalog_client_impl.cpp
+++ b/src/mongo/s/catalog/sharding_catalog_client_impl.cpp
@@ -808,7 +808,7 @@ StatusWith<std::vector<TagsType>> ShardingCatalogClientImpl::getTagsForCollectio
                                               kConfigReadSelector,
                                               repl::ReadConcernLevel::kMajorityReadConcern,
                                               TagsType::ConfigNS,
-                                              BSON(TagsType::ns(nss.ns())),
+                                              BSON(TagsType::ns(nss.ns().toString())),
                                               BSON(TagsType::min() << 1),
                                               boost::none);  // no limit
     if (!findStatus.isOK()) {
diff --git a/src/mongo/s/client/shard_remote.cpp b/src/mongo/s/client/shard_remote.cpp
index 8f7e7443e23..e58cc7c6bca 100644
--- a/src/mongo/s/client/shard_remote.cpp
+++ b/src/mongo/s/client/shard_remote.cpp
@@ -506,7 +506,8 @@ StatusWith<ShardRemote::AsyncCmdHandle> ShardRemote::_scheduleCommand(
     const auto readPrefWithConfigTime = [&]() -> ReadPreferenceSetting {
         // TODO SERVER-74281: Append this higher up when we know we're targeting the config to read
         // metadata or use a better filter to avoid matching logical sessions collection.
-        if (isConfig() && (dbName == DatabaseName::kConfig || dbName == DatabaseName::kAdmin)) {
+        if (isConfig() &&
+            (dbName == DatabaseName::kConfig.db() || dbName == DatabaseName::kAdmin.db())) {
             const auto vcTime = VectorClock::get(opCtx)->getTime();
             ReadPreferenceSetting readPrefToReturn{readPref};
             readPrefToReturn.minClusterTime = vcTime.configTime().asTimestamp();
diff --git a/src/mongo/s/cluster_commands_helpers.cpp b/src/mongo/s/cluster_commands_helpers.cpp
index 1619df5129f..3d431d45952 100644
--- a/src/mongo/s/cluster_commands_helpers.cpp
+++ b/src/mongo/s/cluster_commands_helpers.cpp
@@ -214,7 +214,7 @@ std::vector<AsyncRequestsSender::Response> gatherResponsesImpl(
     MultiStatementTransactionRequestsSender ars(
         opCtx,
         Grid::get(opCtx)->getExecutorPool()->getArbitraryExecutor(),
-        dbName,
+        DatabaseName{dbName},
         requests,
         readPref,
         retryPolicy);
diff --git a/src/mongo/s/commands/cluster_count_cmd.h b/src/mongo/s/commands/cluster_count_cmd.h
index 045b1895728..562957a67d1 100644
--- a/src/mongo/s/commands/cluster_count_cmd.h
+++ b/src/mongo/s/commands/cluster_count_cmd.h
@@ -229,7 +229,7 @@ public:
             return exceptionToStatus();
         }
 
-        const NamespaceString nss(parseNs(request.getDatabase(), cmdObj));
+        const NamespaceString nss = parseNs(DatabaseName{request.getDatabase()}, cmdObj);
         uassert(ErrorCodes::InvalidNamespace,
                 str::stream() << "Invalid namespace specified '" << nss.ns() << "'",
                 nss.isValid());
diff --git a/src/mongo/s/commands/cluster_distinct_cmd.cpp b/src/mongo/s/commands/cluster_distinct_cmd.cpp
index 5fb9a701419..2cf1cdc9062 100644
--- a/src/mongo/s/commands/cluster_distinct_cmd.cpp
+++ b/src/mongo/s/commands/cluster_distinct_cmd.cpp
@@ -111,7 +111,7 @@ public:
                    ExplainOptions::Verbosity verbosity,
                    rpc::ReplyBuilderInterface* result) const override {
         const BSONObj& cmdObj = opMsgRequest.body;
-        const NamespaceString nss(parseNs(opMsgRequest.getDatabase(), cmdObj));
+        const NamespaceString nss(parseNs(DatabaseName{opMsgRequest.getDatabase()}, cmdObj));
 
         auto parsedDistinctCmd =
             ParsedDistinct::parse(opCtx, nss, cmdObj, ExtensionsCallbackNoop(), true);
diff --git a/src/mongo/s/commands/cluster_drop_collection_cmd.cpp b/src/mongo/s/commands/cluster_drop_collection_cmd.cpp
index efbfe0f26ac..38ab0dd6b2d 100644
--- a/src/mongo/s/commands/cluster_drop_collection_cmd.cpp
+++ b/src/mongo/s/commands/cluster_drop_collection_cmd.cpp
@@ -100,7 +100,7 @@ public:
 
                 // Send it to the primary shard
                 ShardsvrDropCollection dropCollectionCommand(nss);
-                dropCollectionCommand.setDbName(nss.db());
+                dropCollectionCommand.setDbName(DatabaseName{nss.db()});
                 dropCollectionCommand.setCollectionUUID(request().getCollectionUUID());
 
                 auto cmdResponse = executeCommandAgainstDatabasePrimary(
diff --git a/src/mongo/s/commands/cluster_move_primary_cmd.cpp b/src/mongo/s/commands/cluster_move_primary_cmd.cpp
index e401f4811ea..72c5219ea42 100644
--- a/src/mongo/s/commands/cluster_move_primary_cmd.cpp
+++ b/src/mongo/s/commands/cluster_move_primary_cmd.cpp
@@ -96,7 +96,7 @@ public:
                      const BSONObj& cmdObj,
                      BSONObjBuilder& result) {
         auto request = MovePrimary::parse(IDLParserContext("MovePrimary"), cmdObj);
-        const string db = parseNs(dbName, cmdObj).dbName().db();
+        const string db = parseNs(dbName, cmdObj).dbName().db().toString();
         const StringData toShard(request.getTo());
 
         // Invalidate the routing table cache entry for this database so that we reload the
diff --git a/src/mongo/s/commands/cluster_rename_collection_cmd.cpp b/src/mongo/s/commands/cluster_rename_collection_cmd.cpp
index 11c3de553c7..8bb453273b8 100644
--- a/src/mongo/s/commands/cluster_rename_collection_cmd.cpp
+++ b/src/mongo/s/commands/cluster_rename_collection_cmd.cpp
@@ -91,7 +91,7 @@ public:
                 request().getDropTarget());
 
             ShardsvrRenameCollection renameCollRequest(fromNss);
-            renameCollRequest.setDbName(fromNss.db());
+            renameCollRequest.setDbName(DatabaseName{fromNss.db()});
             renameCollRequest.setRenameCollectionRequest(renameCollReq);
             renameCollRequest.setAllowEncryptedCollectionRename(
                 AuthorizationSession::get(opCtx->getClient())
diff --git a/src/mongo/s/commands/cluster_set_cluster_parameter_cmd.cpp b/src/mongo/s/commands/cluster_set_cluster_parameter_cmd.cpp
index 3e26d8101e3..9cb643ff895 100644
--- a/src/mongo/s/commands/cluster_set_cluster_parameter_cmd.cpp
+++ b/src/mongo/s/commands/cluster_set_cluster_parameter_cmd.cpp
@@ -66,7 +66,7 @@ public:
         void typedRun(OperationContext* opCtx) {
             ConfigsvrSetClusterParameter configsvrSetClusterParameter(
                 request().getCommandParameter());
-            configsvrSetClusterParameter.setDbName(ns().db());
+            configsvrSetClusterParameter.setDbName(DatabaseName{ns().db()});
 
             const auto configShard = Grid::get(opCtx)->shardRegistry()->getConfigShard();
 
diff --git a/src/mongo/s/commands/cluster_set_feature_compatibility_version_cmd.cpp b/src/mongo/s/commands/cluster_set_feature_compatibility_version_cmd.cpp
index 2f88401dc30..2a12e87911f 100644
--- a/src/mongo/s/commands/cluster_set_feature_compatibility_version_cmd.cpp
+++ b/src/mongo/s/commands/cluster_set_feature_compatibility_version_cmd.cpp
@@ -99,7 +99,7 @@ public:
             auto response = uassertStatusOK(configShard->runCommandWithFixedRetryAttempts(
                 opCtx,
                 ReadPreferenceSetting{ReadPreference::PrimaryOnly},
-                cmd.getDbName().db(),
+                cmd.getDbName().db().toString(),
                 CommandHelpers::appendMajorityWriteConcern(cmd.toBSON({}),
                                                            opCtx->getWriteConcern()),
                 Shard::RetryPolicy::kIdempotent));
diff --git a/src/mongo/s/commands/cluster_shard_collection_cmd.cpp b/src/mongo/s/commands/cluster_shard_collection_cmd.cpp
index cab047e6ade..077a1c56a54 100644
--- a/src/mongo/s/commands/cluster_shard_collection_cmd.cpp
+++ b/src/mongo/s/commands/cluster_shard_collection_cmd.cpp
@@ -112,7 +112,7 @@ public:
         requestParamsObj.setImplicitlyCreateIndex(shardCollRequest.getImplicitlyCreateIndex());
         requestParamsObj.setEnforceUniquenessCheck(shardCollRequest.getEnforceUniquenessCheck());
         shardsvrCollRequest.setCreateCollectionRequest(std::move(requestParamsObj));
-        shardsvrCollRequest.setDbName(nss.db());
+        shardsvrCollRequest.setDbName(DatabaseName{nss.db()});
 
         cluster::createCollection(opCtx, shardsvrCollRequest);
 
diff --git a/src/mongo/s/commands/cluster_transition_to_catalog_shard_cmd.cpp b/src/mongo/s/commands/cluster_transition_to_catalog_shard_cmd.cpp
index 10ed514dfdd..ea9ffaa6cf2 100644
--- a/src/mongo/s/commands/cluster_transition_to_catalog_shard_cmd.cpp
+++ b/src/mongo/s/commands/cluster_transition_to_catalog_shard_cmd.cpp
@@ -67,7 +67,7 @@ public:
                     gFeatureFlagCatalogShard.isEnabled(serverGlobalParams.featureCompatibility));
 
             ConfigsvrTransitionToCatalogShard cmdToSend;
-            cmdToSend.setDbName({"admin"});
+            cmdToSend.setDbName(DatabaseName::kAdmin);
 
             auto configShard = Grid::get(opCtx)->shardRegistry()->getConfigShard();
 
diff --git a/src/mongo/s/commands/cluster_transition_to_dedicated_config_server_cmd.cpp b/src/mongo/s/commands/cluster_transition_to_dedicated_config_server_cmd.cpp
index dc5001cf5b5..50f322ed1c9 100644
--- a/src/mongo/s/commands/cluster_transition_to_dedicated_config_server_cmd.cpp
+++ b/src/mongo/s/commands/cluster_transition_to_dedicated_config_server_cmd.cpp
@@ -90,7 +90,7 @@ public:
         auto configShard = Grid::get(opCtx)->shardRegistry()->getConfigShard();
 
         ConfigsvrTransitionToDedicatedConfig transitionToDedicatedConfigServer;
-        transitionToDedicatedConfigServer.setDbName({"admin"});
+        transitionToDedicatedConfigServer.setDbName(DatabaseName::kAdmin);
 
         // Force a reload of this node's shard list cache at the end of this command.
         auto cmdResponseWithStatus = configShard->runCommandWithFixedRetryAttempts(
diff --git a/src/mongo/s/commands/internal_transactions_test_command.h b/src/mongo/s/commands/internal_transactions_test_command.h
index ac1252beab9..083d4bc0a12 100644
--- a/src/mongo/s/commands/internal_transactions_test_command.h
+++ b/src/mongo/s/commands/internal_transactions_test_command.h
@@ -102,7 +102,7 @@ public:
                             continue;
                         }
 
-                        const auto res = txnClient.runCommandSync(dbName, command);
+                        const auto res = txnClient.runCommandSync(DatabaseName{dbName}, command);
 
                         sharedBlock->responses.emplace_back(
                             CommandHelpers::filterCommandReplyForPassthrough(
diff --git a/src/mongo/s/query_analysis_client.cpp b/src/mongo/s/query_analysis_client.cpp
index cd66f1beb7d..5651d403209 100644
--- a/src/mongo/s/query_analysis_client.cpp
+++ b/src/mongo/s/query_analysis_client.cpp
@@ -169,7 +169,7 @@ void QueryAnalysisClient::insert(OperationContext* opCtx,
     auto insertCmdObj = insertCmd.toBSON(
         {BSON(WriteConcernOptions::kWriteConcernField << kMajorityWriteConcern.toBSON())});
 
-    executeCommandOnPrimary(opCtx, nss.db(), std::move(insertCmdObj), uassertCmdStatusFn);
+    executeCommandOnPrimary(opCtx, nss.dbName(), std::move(insertCmdObj), uassertCmdStatusFn);
 }
 
 }  // namespace analyze_shard_key
diff --git a/src/mongo/util/assert_util_core.h b/src/mongo/util/assert_util_core.h
index 852ca464f17..61e4b8c1ca8 100644
--- a/src/mongo/util/assert_util_core.h
+++ b/src/mongo/util/assert_util_core.h
@@ -87,12 +87,9 @@ MONGO_COMPILER_NORETURN void invariantFailedWithMsg(const char* expr,
 //
 //       Invariant failure !condition "hello!" some/file.cpp 528
 //
-#define MONGO_invariant_2(Expression, contextExpr)                                           \
-    ::mongo::invariantWithContextAndLocation((Expression),                                   \
-                                             #Expression,                                    \
-                                             [&]() -> std::string { return (contextExpr); }, \
-                                             __FILE__,                                       \
-                                             __LINE__)
+#define MONGO_invariant_2(Expression, contextExpr) \
+    ::mongo::invariantWithContextAndLocation(      \
+        (Expression), #Expression, [&] { return std::string{contextExpr}; }, __FILE__, __LINE__)
 
 template <typename T, typename ContextExpr>
 inline void invariantWithContextAndLocation(