Buffer locking is special (hints, checksums, AIO writes) #158
Description
--- As of 2026-02-08T18:38:42.000Z ---
Andres Freund and Heikki Linnakangas are discussing buffer management optimizations related to WAL logging order and checkpoint handling. Heikki confirmed that patch 0004 switching to standard order in MarkBufferDirtyHint() is correct, eliminating the need to delay checkpoint starts. They're debating the "small window" where unnecessary WAL records might be generated when checkpoints start between buffer dirtying and redo pointer checks. Andres raises concerns about a complex scenario involving full page images (FPI) and torn page writes during checkpoints, suggesting the current conservative approach may be necessary to prevent recovery issues. He outlines a seven-step scenario where insufficient FPI generation could lead to unrecoverable torn pages. Both developers acknowledge potential improvements to reduce WAL spikes during checkpoint starts, though the implementation appears more complicated than initially thought.
Andres Freund和Heikki Linnakangas正在讨论与WAL日志记录顺序和检查点处理相关的缓冲区管理优化。Heikki确认了补丁0004在MarkBufferDirtyHint()中切换到标准顺序是正确的，消除了延迟检查点启动的需要。他们正在讨论在缓冲区变脏和redo指针检查之间启动检查点时可能生成不必要WAL记录的"小窗口"问题。Andres提出了关于涉及全页镜像(FPI)和检查点期间页面撕裂写入的复杂场景的担忧，建议当前的保守方法可能是防止恢复问题所必需的。他概述了一个七步场景，其中FPI生成不足可能导致不可恢复的撕裂页面。两位开发者都认识到减少检查点启动期间WAL峰值的潜在改进，尽管实现看起来比最初想象的更复杂。
participants - 参与者: