Re: sync_file_range() - Mailing list pgsql-hackers

From Qingqing Zhou
Subject Re: sync_file_range()
Date
Msg-id e75juu$1ou4$1@news.hub.org
Whole thread Raw
In response to sync_file_range()  (Christopher Kings-Lynne <chris.kings-lynne@calorieking.com>)
Responses Re: sync_file_range()  (ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp>)
Re: sync_file_range()  (Simon Riggs <simon@2ndquadrant.com>)
List pgsql-hackers
"ITAGAKI Takahiro" <itagaki.takahiro@oss.ntt.co.jp> wrote
>
>
> I'm interested in it, with which we could improve responsiveness during
> checkpoints. Though it is Linux specific system call, but we could use
> the combination of mmap() and msync() instead of it; I mean we can use
> mmap only to flush dirty pages, not to read or write pages.
>

Can you specify details? As the TODO item inidcates, if we mmap data file, a
serious problem is that we don't know when the data pages hit the disks -- 
so that we may voilate the WAL rule.

Regards,
Qingqing




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