Re: [HACKERS] Moving relation extension locks out of heavyweight lock manager

On Thu, Dec 14, 2017 at 5:45 AM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> Here is the result.
> I've measured the through-put with some cases on my virtual machine.
> Each client loads 48k file to each different relations located on
> either xfs filesystem or ext4 filesystem, for 30 sec.
>
> Case 1: COPYs to relations on different filessystems(xfs and ext4) and
> N_RELEXTLOCK_ENTS is 1024
>
> clients = 2, avg = 296.2068
> clients = 5, avg = 372.0707
> clients = 10, avg = 389.8850
> clients = 50, avg = 428.8050
>
> Case 2: COPYs to relations on different filessystems(xfs and ext4) and
> N_RELEXTLOCK_ENTS is 1
>
> clients = 2, avg = 294.3633
> clients = 5, avg = 358.9364
> clients = 10, avg = 383.6945
> clients = 50, avg = 424.3687
>
> And the result of current HEAD is following.
>
> clients = 2, avg = 284.9976
> clients = 5, avg = 356.1726
> clients = 10, avg = 375.9856
> clients = 50, avg = 429.5745
>
> In case2, the through-put got decreased compare to case 1 but it seems
> to be almost same as current HEAD. Because the speed of acquiring and
> releasing extension lock got x10 faster than current HEAD as I
> mentioned before, the performance degradation may not have gotten
> decreased than I expected even in case 2.
> Since my machine doesn't have enough resources the result of clients =
> 50 might not be a valid result.

I have to admit that result is surprising to me.

--
Robert Haas
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