diff options
Diffstat (limited to 'src/mongo/db/clientcursor.h')
| -rw-r--r-- | src/mongo/db/clientcursor.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/src/mongo/db/clientcursor.h b/src/mongo/db/clientcursor.h index 121566cbdb8..89239e6230d 100644 --- a/src/mongo/db/clientcursor.h +++ b/src/mongo/db/clientcursor.h @@ -541,6 +541,20 @@ private: OperationContext* _opCtx = nullptr; ClientCursor* _cursor = nullptr; CursorManager* _cursorManager = nullptr; + + // A pinned cursor takes ownership of storage resources (storage-level cursors owned by the + // PlanExecutor) without lock-manager locks. Such an operation must ensure interruptibility when + // later acquiring a lock in order to avoid deadlocking with replication rollback at the storage + // engine level. Rollback signals interrupt to active readers, acquires a global X lock and then + // waits for all storage cursors to be closed in order to proceed; while a pinned cursor + // operation holds storage-level cursors and then may try to acquire a lock. + // + // An operation holding a pinned cursor must never have an UninterruptibleLockGuard on the stack + // that causes lock acquisition to hang without checking for interrupt. This + // InterruptibleLockGuard ensures that operations holding a ClientCursorPin will eventually + // observe and obey interrupt signals in the locking layer. + std::unique_ptr<InterruptibleLockGuard> _interruptibleLockGuard; + bool _shouldSaveRecoveryUnit = false; }; |