buffer-manager

The PostgreSQL buffer manager enforces strict pin and unpin discipline through BufferDesc state bits and atomic state transitions, preventing buffer refcount leaks by ensuring pages are safely held in shared memory during access.

Clock-sweep replacement is PostgreSQL's buffer eviction algorithm that cycles through the shared buffer pool, selecting unpinned buffers for reuse to maintain efficient memory utilization without discarding frequently accessed pages.

Debug a buffer refcount leak warning by analyzing the pin and unpin lifecycle in your source code, checking LWLock acquisition order, and verifying atomic state transitions against the safety checklists provided for bufmgr.c modifications.

Implement a custom BufferAccessStrategy by adding new ring buffers to the storage layer, following structured patch checklists to ensure correct shared-memory page cache access and prevent inefficient buffer eviction during bulk operations.

Yes, modifying PostgreSQL storage layer functionality requires deep knowledge of LWLocks, BufferDesc state bits, and atomic state transitions to ensure memory safety and correct locking order when extending shared-buffer operations.

Incorrect locking order errors occur when shared-memory page cache operations acquire LWLocks in the wrong sequence, which can be resolved by reviewing atomic state transitions and pin and unpin discipline requirements.