SERVER-39847 Migrating session info can trigger fassert when destination shard has transaction history truncated by oplog

(cherry picked from commit 1466c2b24eef41805dfac73e2fb43256d6d8fae7)

1 files changed, 6 insertions, 7 deletions

diff --git a/src/mongo/db/session.cpp b/src/mongo/db/session.cpp
index a6ceba98b45..659ca1c3cc4 100644
--- a/src/mongo/db/session.cpp
+++ b/src/mongo/db/session.cpp
@@ -445,18 +445,17 @@ bool Session::onMigrateBeginOnPrimary(OperationContext* opCtx, TxnNumber txnNumb
             return false;
         }
     } catch (const DBException& ex) {
-        // If the transaction chain was truncated on the recipient shard, then we are most likely
-        // copying from a session that hasn't been touched on the recipient shard for a very long
-        // time but could be recent on the donor.
-        //
-        // We continue copying regardless to get the entire transaction from the donor.
-        if (ex.code() != ErrorCodes::IncompleteTransactionHistory) {
-            throw;
+        // If the transaction chain is incomplete because oplog was truncated, just ignore the
+        // incoming oplog and don't attempt to 'patch up' the missing pieces.
+        if (ex.code() == ErrorCodes::IncompleteTransactionHistory) {
+            return false;
         }
 
         if (stmtId == kIncompleteHistoryStmtId) {
             return false;
         }
+
+        throw;
     }
 
     return true;