SERVER-21693 generate a summary after rollback via recover to timestamp

1 files changed, 57 insertions, 0 deletions

diff --git a/src/mongo/db/repl/rollback_impl.h b/src/mongo/db/repl/rollback_impl.h
index bd671ff5309..9be56195c22 100644
--- a/src/mongo/db/repl/rollback_impl.h
+++ b/src/mongo/db/repl/rollback_impl.h
@@ -47,6 +47,55 @@ class ReplicationCoordinator;
 class ReplicationProcess;
 
 /**
+ * Tracks statistics about rollback, and is used to generate a summary about what has occurred.
+ * Because it is possible for rollback to exit early, fields are initialized to boost::none and are
+ * populated with actual values during the rollback process.
+ */
+struct RollbackStats {
+    /**
+     * The wall clock time when rollback started.
+     */
+    Date_t startTime;
+
+    /**
+     * The wall clock time when rollback completed, either successfully or unsuccessfully.
+     */
+    Date_t endTime;
+
+    /**
+     * The id number generated for this rollback event.
+     */
+    boost::optional<int> rollbackId;
+
+    /**
+     * The last optime on the branch of history being rolled back.
+     */
+    boost::optional<OpTime> lastLocalOptime;
+
+    /**
+     * The optime of the latest shared oplog entry between this node and the sync source.
+     */
+    boost::optional<OpTime> commonPoint;
+
+    /**
+     * The value of the oplog truncate timestamp. This is the timestamp of the entry immediately
+     * after the common point on the local oplog (that is, on the branch of history being rolled
+     * back).
+     */
+    boost::optional<Timestamp> truncateTimestamp;
+
+    /**
+     * The value of the stable timestamp to which rollback recovered.
+     */
+    boost::optional<Timestamp> stableTimestamp;
+
+    /**
+     * The directory containing rollback data files, if any were written.
+     */
+    boost::optional<std::string> rollbackDataFileDirectory;
+};
+
+/**
  * During steady state replication, it is possible to find the local server in a state where it
  * cannot replicate from a sync source. This can happen if the local server has gone offline and
  * comes back to find a new primary with an inconsistent set of operations in its oplog from the
@@ -335,6 +384,11 @@ private:
     Status _writeRollbackFiles(OperationContext* opCtx);
 
     /**
+     * Logs a summary of what has occurred so far during rollback to the server log.
+     */
+    void _summarizeRollback(OperationContext* opCtx) const;
+
+    /**
      * Aligns the drop pending reaper's state with the catalog.
      */
     void _resetDropPendingState(OperationContext* opCtx);
@@ -366,6 +420,9 @@ private:
     // Contains information about the rollback that will be passed along to the rollback OpObserver
     // method.
     OpObserver::RollbackObserverInfo _observerInfo = {};  // (N)
+
+    // Holds information about this rollback event.
+    RollbackStats _rollbackStats;  // (N)
 };
 
 }  // namespace repl