Re: PostgreSQL's handling of fsync() errors is unsafe and risks data loss at least on XFS

I covered this in my original post.

Yes, we check the return value. But what do we do about it? For fsyncs of heap files, we ERROR, aborting the checkpoint. We'll retry the checkpoint later, which will retry the fsync(). **Which will now appear to succeed** because the kernel forgot that it lost our writes after telling us the first time. So we do check the error code, which returns success, and we complete the checkpoint and move on.

But we only retried the fsync, not the writes before the fsync.