SERVER-41312 Ban internalReadAtClusterTime in transactions

2 files changed, 30 insertions, 1 deletions

diff --git a/jstests/replsets/read_at_cluster_time_outside_transactions.js b/jstests/replsets/read_at_cluster_time_outside_transactions.js
index 1d507962dc6..af0bbf9cf4f 100644
--- a/jstests/replsets/read_at_cluster_time_outside_transactions.js
+++ b/jstests/replsets/read_at_cluster_time_outside_transactions.js
@@ -2,7 +2,7 @@
  * Tests that the "find" and "dbHash" commands support reading at a Timestamp by using the
  * $_internalReadAtClusterTime option.
  *
- * @tags: [requires_document_locking]
+ * @tags: [requires_document_locking, uses_transactions]
  */
 (function() {
     "use strict";
@@ -111,6 +111,29 @@
     }),
                                  ErrorCodes.InvalidOptions);
 
+    // $_internalReadAtClusterTime is not supported in transactions.
+    const session = primary.startSession();
+    const sessionDB = session.getDatabase("test");
+    const sessionColl = sessionDB[collName];
+
+    session.startTransaction();
+    assert.commandFailedWithCode(sessionColl.runCommand("find", {
+        batchSize: 2,
+        sort: {_id: 1},
+        $_internalReadAtClusterTime: clusterTime,
+    }),
+                                 ErrorCodes.OperationNotSupportedInTransaction);
+    assert.commandFailedWithCode(session.abortTransaction_forTesting(),
+                                 ErrorCodes.NoSuchTransaction);
+
+    // dbHash is not supported in transactions at all.
+    session.startTransaction();
+    assert.commandFailedWithCode(
+        sessionDB.runCommand({dbHash: 1, $_internalReadAtClusterTime: clusterTime}),
+        ErrorCodes.OperationNotSupportedInTransaction);
+    assert.commandFailedWithCode(session.abortTransaction_forTesting(),
+                                 ErrorCodes.NoSuchTransaction);
+
     // Create a new collection to move the minimum visible snapshot to that operation time. Then
     // read at a cluster time behind the minimum visible snapshot which should fail.
     let newCollName = "newColl";
diff --git a/src/mongo/db/commands/find_cmd.cpp b/src/mongo/db/commands/find_cmd.cpp
index 7e386af97c3..90ded58d209 100644
--- a/src/mongo/db/commands/find_cmd.cpp
+++ b/src/mongo/db/commands/find_cmd.cpp
@@ -286,6 +286,12 @@ public:
                     " commands are enabled",
                     !qr->getReadAtClusterTime() || getTestCommandsEnabled());
 
+            uassert(
+                ErrorCodes::OperationNotSupportedInTransaction,
+                "The '$_internalReadAtClusterTime' option is not supported within a transaction.",
+                !txnParticipant || !txnParticipant.inActiveOrKilledMultiDocumentTransaction() ||
+                    !qr->getReadAtClusterTime());
+
             uassert(ErrorCodes::InvalidOptions,
                     "The '$_internalReadAtClusterTime' option is only supported when replication is"
                     " enabled",