2 files changed, 59 insertions, 3 deletions
diff --git a/jstests/core/write_error_message_truncation.js b/jstests/core/write_error_message_truncation.js
new file mode 100644
index 00000000000..3a7a33ec86f
--- /dev/null
+++ b/jstests/core/write_error_message_truncation.js
@@ -0,0 +1,42 @@
+/**
+ * Tests that the write error messages' strings are truncated properly.
+ *
+ * @tags: [
+ *   assumes_write_concern_unchanged,
+ * ]
+ */
+
+(function() {
+'use strict';
+
+var coll = db.write_error_message_truncation;
+coll.drop();
+
+// Insert 3 documents that we will then reinsert in order to generate DuplicateKey errors
+assert.writeOK(coll.insert(
+    [
+        {_id: 0},
+        {_id: 1},
+        {_id: 2},
+    ],
+    {writeConcern: {w: 'majority'}, ordered: true}));
+
+// Ensure DuplicateKey errors during insert all report their messages
+var res = coll.insert(
+    [
+        {_id: 0},
+        {_id: 1},
+        {_id: 2},
+    ],
+    {writeConcern: {w: 'majority'}, ordered: false});
+
+jsTest.log(res.getRawResponse());
+
+assert.eq(0, res.nInserted);
+
+var writeErrors = res.getWriteErrors();
+assert.eq(3, writeErrors.length);
+assert.neq('', writeErrors[0].errmsg);
+assert.neq('', writeErrors[1].errmsg);
+assert.neq('', writeErrors[2].errmsg);
+})();
diff --git a/src/mongo/db/commands/write_commands.cpp b/src/mongo/db/commands/write_commands.cpp
index 0b671d5a8aa..d562d21a00e 100644
--- a/src/mongo/db/commands/write_commands.cpp
+++ b/src/mongo/db/commands/write_commands.cpp
@@ -340,12 +340,26 @@ boost::optional<write_ops::WriteError> generateError(OperationContext* opCtx,
         if (ErrorCodes::isInterruption(*overwrittenStatus)) {
             uassertStatusOK(*overwrittenStatus);
         }
+
+        // Tenant migration errors, similarly to migration errors consume too much space in the
+        // ordered:false responses and get truncated. Since the call to
+        // 'handleTenantMigrationConflict' above replaces the original status, we need to manually
+        // truncate the new reason if the original 'status' was also truncated.
+        if (status.reason().empty()) {
+            overwrittenStatus = overwrittenStatus->withReason("");
+        }
     }
 
     constexpr size_t kMaxErrorReasonsToReport = 1;
-    if (numErrors >= kMaxErrorReasonsToReport)
-        overwrittenStatus =
-            overwrittenStatus ? overwrittenStatus->withReason("") : status.withReason("");
+    constexpr size_t kMaxErrorSizeToReportAfterMaxReasonsReached = 1024 * 1024;
+
+    if (numErrors > kMaxErrorReasonsToReport) {
+        size_t errorSize =
+            overwrittenStatus ? overwrittenStatus->reason().size() : status.reason().size();
+        if (errorSize > kMaxErrorSizeToReportAfterMaxReasonsReached)
+            overwrittenStatus =
+                overwrittenStatus ? overwrittenStatus->withReason("") : status.withReason("");
+    }
 
     if (overwrittenStatus)
         return write_ops::WriteError(index, std::move(*overwrittenStatus));