SERVER-24883 cloner should not create _id index when original collection doesn't have one

1 files changed, 9 insertions, 1 deletions

diff --git a/src/mongo/db/cloner.cpp b/src/mongo/db/cloner.cpp
index 91fa3d94b75..9d4a5165424 100644
--- a/src/mongo/db/cloner.cpp
+++ b/src/mongo/db/cloner.cpp
@@ -618,7 +618,15 @@ Status Cloner::copyDb(OperationContext* txn,
             uassert(18645, str::stream() << "database " << toDBName << " dropped during clone", db);
 
             Collection* c = db->getCollection(to_name);
-            if (c && !c->getIndexCatalog()->haveIdIndex(txn)) {
+            bool autoIndexId = true;
+            auto status =
+                bsonExtractBooleanFieldWithDefault(options, "autoIndexId", true, &autoIndexId);
+            if (!status.isOK()) {
+                return status;
+            }
+
+            if (c && !c->getIndexCatalog()->haveIdIndex(txn) && autoIndexId) {
+
                 // We need to drop objects with duplicate _ids because we didn't do a true
                 // snapshot and this is before applying oplog operations that occur during the
                 // initial sync.