SERVER-46119: Added runtime server parameter to disable collection and index creation in multi document transactions.

 create mode 100644 src/mongo/db/commands_in_multi_doc_txn_params.idl

4 files changed, 56 insertions, 2 deletions

diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index 131cfc1a228..f93d37a0f6f 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -514,6 +514,7 @@ env.Library(
     target="commands",
     source=[
         'commands.cpp',
+        env.Idlc('commands_in_multi_doc_txn_params.idl')[0],
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/base',
diff --git a/src/mongo/db/commands.cpp b/src/mongo/db/commands.cpp
index 142037458bb..b2187a0e697 100644
--- a/src/mongo/db/commands.cpp
+++ b/src/mongo/db/commands.cpp
@@ -49,6 +49,7 @@
 #include "mongo/db/client.h"
 #include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands/test_commands_enabled.h"
+#include "mongo/db/commands_in_multi_doc_txn_params_gen.h"
 #include "mongo/db/curop.h"
 #include "mongo/db/error_labels.h"
 #include "mongo/db/jsobj.h"
@@ -110,8 +111,7 @@ bool checkAuthorizationImplPreParse(OperationContext* opCtx,
 }
 
 // The command names that are allowed in a multi-document transaction.
-const StringMap<int> txnCmdWhitelistFCV44 = {
-    {"create", 1}, {"createIndexes", 1}, {"_configsvrCreateCollection", 1}};
+const StringMap<int> txnCmdWhitelistFCV44 = {{"create", 1}, {"createIndexes", 1}};
 const StringMap<int> txnCmdWhitelist = {{"abortTransaction", 1},
                                         {"aggregate", 1},
                                         {"commitTransaction", 1},
@@ -496,6 +496,15 @@ void CommandHelpers::canUseTransactions(const NamespaceString& nss,
             str::stream() << "Cannot run '" << cmdName << "' in a multi-document transaction.",
             inTxnWhitelist || inTxnWhitelistFCV44);
 
+    if (cmdName == "createCollection"_sd || cmdName == "createIndexes"_sd) {
+        uassert(ErrorCodes::OperationNotSupportedInTransaction,
+                str::stream() << "Cannot run '" << cmdName
+                              << "' in a multi-document transaction "
+                                 "because creation of collections and "
+                                 "indexes inside multi-document transactions is disabled.",
+                gShouldMultiDocTxnCreateCollectionAndIndexes.load());
+    }
+
     const auto dbName = nss.db();
 
     uassert(ErrorCodes::OperationNotSupportedInTransaction,
diff --git a/src/mongo/db/commands_in_multi_doc_txn_params.idl b/src/mongo/db/commands_in_multi_doc_txn_params.idl
new file mode 100644
index 00000000000..f9f0568286a
--- /dev/null
+++ b/src/mongo/db/commands_in_multi_doc_txn_params.idl
@@ -0,0 +1,37 @@
+# Copyright (C) 2020-present MongoDB, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the Server Side Public License, version 1,
+# as published by MongoDB, Inc.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# Server Side Public License for more details.
+#
+# You should have received a copy of the Server Side Public License
+# along with this program. If not, see
+# <http://www.mongodb.com/licensing/server-side-public-license>.
+#
+# As a special exception, the copyright holders give permission to link the
+# code of portions of this program with the OpenSSL library under certain
+# conditions as described in each individual source file and distribute
+# linked combinations including the program with the OpenSSL library. You
+# must comply with the Server Side Public License in all respects for
+# all of the code used other than as permitted herein. If you modify file(s)
+# with this exception, you may extend this exception to your version of the
+# file(s), but you are not obligated to do so. If you do not wish to do so,
+# delete this exception statement from your version. If you delete this
+# exception statement from all source files in the program, then also delete
+# it in the license file.
+#
+global:
+    cpp_namespace: "mongo"
+
+server_parameters:
+    shouldMultiDocTxnCreateCollectionAndIndexes:
+        description: 'Enable ability to create new collections and indexes inside multi-document transactions. Default is true.'
+        set_at: [ startup, runtime ]
+        cpp_varname: 'gShouldMultiDocTxnCreateCollectionAndIndexes'
+        cpp_vartype: 'AtomicWord<bool>'
+        default: true
diff --git a/src/mongo/db/ops/write_ops_exec.cpp b/src/mongo/db/ops/write_ops_exec.cpp
index 8ebd6c54a8c..be883aa7013 100644
--- a/src/mongo/db/ops/write_ops_exec.cpp
+++ b/src/mongo/db/ops/write_ops_exec.cpp
@@ -42,6 +42,7 @@
 #include "mongo/db/catalog/document_validation.h"
 #include "mongo/db/catalog_raii.h"
 #include "mongo/db/commands.h"
+#include "mongo/db/commands_in_multi_doc_txn_params_gen.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
 #include "mongo/db/curop_failpoint_helpers.h"
 #include "mongo/db/curop_metrics.h"
@@ -226,6 +227,12 @@ void makeCollection(OperationContext* opCtx, const NamespaceString& ns) {
                 << " in multi-document transaction unless featureCompatibilityVersion is 4.4.",
             isFullyUpgradedTo44 || !inTransaction);
 
+    uassert(ErrorCodes::OperationNotSupportedInTransaction,
+            str::stream() << "Cannot create namespace " << ns.ns()
+                          << "because creation of collections and indexes inside "
+                             "multi-document transactions is disabled.",
+            !inTransaction || gShouldMultiDocTxnCreateCollectionAndIndexes.load());
+
     writeConflictRetry(opCtx, "implicit collection creation", ns.ns(), [&opCtx, &ns] {
         AutoGetOrCreateDb db(opCtx, ns.db(), MODE_IX);
         Lock::CollectionLock collLock(opCtx, ns, MODE_IX);