(2013/09/30 13:55), Amit Kapila wrote:
On Mon, Sep 30, 2013 at 10:04 AM, Fujii Masao <masao.fu...@gmail.com> wrote:
Yep, please! It's really helpful!
OK! I test with single instance and synchronous replication constitution.
By the way, you posted patch which is sync_file_range() WAL writing method in 3
years ago. I think it is also good for performance. As the reason, I read
sync_file_range() and fdatasync() in latest linux kernel code(3.9.11),
fdatasync() writes in dirty buffers of the whole file, on the other hand,
sync_file_range() writes in partial dirty buffers. In more detail, these
functions use the same function in kernel source code, fdatasync() is
vfs_fsync_range(file, 0, LLONG_MAX, 1), and sync_file_range() is
vfs_fsync_range(file, offset, amount, 1).
It is obvious that which is more efficiently in WAL writing.
You had better confirm it in linux kernel's git. I think your conviction will be
more deeply.
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/fs/sync.c?id=refs/tags/v3.11.2
I think it will be useful if you can get the data for 1 and 2 threads
(may be with pgbench itself) as well, because the WAL reduction is
almost sure, but the only thing is that it should not dip tps in some
of the scenarios.
That's right. I also want to know about this patch in MD environment, because
MD has strong point in sequential write which like WAL writing.
Regards,
--
Mitsumasa KONDO
NTT Open Source Software Center
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