SERVER-30818 Wait for all background index builds to complete before starting rollback to checkpoint

1 files changed, 15 insertions, 0 deletions

diff --git a/src/mongo/db/repl/rollback_impl.h b/src/mongo/db/repl/rollback_impl.h
index b8a6b5b04cf..c88899e70b0 100644
--- a/src/mongo/db/repl/rollback_impl.h
+++ b/src/mongo/db/repl/rollback_impl.h
@@ -100,6 +100,11 @@ public:
         virtual void onTransitionToRollback() noexcept {}
 
         /**
+         * Function called after all background index builds have completed.
+         */
+        virtual void onBgIndexesComplete() noexcept {}
+
+        /**
          * Function called after we find the common point.
          */
         virtual void onCommonPointFound(Timestamp commonPoint) noexcept {}
@@ -169,6 +174,16 @@ private:
     Status _transitionToRollback(OperationContext* opCtx);
 
     /**
+     * Waits for any in-progress background index builds to complete. We do this before beginning
+     * the rollback process to prevent any issues surrounding index builds pausing/resuming around a
+     * call to 'recoverToStableTimestamp'. It's not clear that an index build, resumed in this way,
+     * that continues until completion, would be consistent with the collection data. Waiting for
+     * all background index builds to complete is a conservative approach, to avoid any of these
+     * potential issues.
+     */
+    Status _awaitBgIndexCompletion(OperationContext* opCtx);
+
+    /**
      * Recovers to the stable timestamp while holding the global exclusive lock.
      */
     Status _recoverToStableTimestamp(OperationContext* opCtx);