(2014/01/16 21:38), Aidan Van Dyk wrote:
> Can we just get the backend that dirties the page to the posix_fadvice DONTNEED?
No, it can remove clean page in OS file caches. Because if page is dirtied, it
cause physical-disk-writing. However, it is experimental patch so it might be
changed by future benchmark testing.
> Or have another helper that sweeps the shared buffers and does this post-first-dirty?
We can add DropDuplicateOSCache() function to checkpointer process or other
process. And we can chenged posix_fadvice() DONTNEED to sync_file_range(). It can
cause physical-disk-writing in target buffer, not to free OS file caches.
I'm considering that sync_file_range() SYNC_FILE_RANGE_WAIT_BEFORE |
SYNC_FILE_RANGE_WRITE in executing checkpoint. It can avoid fsync freeze
situaition in part of of finnal checkpoint.
Regards,
--
Mitsumasa KONDO
NTT Open Source Software Center