Re: [WIP PATCH] for Performance Improvement in Buffer Management

On Mon, Nov 19, 2012 at 8:52 PM, Amit kapila <amit(dot)kapila(at)huawei(dot)com> wrote:

> On Monday, November 19, 2012 5:53 AM Jeff Janes wrote:
> On Sun, Oct 21, 2012 at 12:59 AM, Amit kapila <amit(dot)kapila(at)huawei(dot)com>
> wrote:
> > On Saturday, October 20, 2012 11:03 PM Jeff Janes wrote:
> >
> >>Run the modes in reciprocating order?
> >> Sorry, I didn't understood this, What do you mean by modes in
> reciprocating order?
>
> > Sorry for the long delay. In your scripts, it looks like you always
> > run the unpatched first, and then the patched second.
>
> Yes, thats true.
>
> > By reciprocating, I mean to run them in the reverse order, or in random
> order.
>
> Today for some configurations, I have ran by reciprocating the order.
> Below are readings:
> Configuration
> 16GB (Database) -7GB (Shared Buffers)
>
> Here i had run in following order
> 1. Run perf report with patch for 32 client
> 2. Run perf report without patch for 32 client
> 3. Run perf report with patch for 16 client
> 4. Run perf report without patch for 16 client
>
> Each execution is 5 minutes,
> 16 client /16 thread | 32 client /32 thread
> @mv-free-lst @9.3devl | @mv-free-lst @9.3devl
> -------------------------------------------------------
> 3669 4056 | 5356 5258
> 3987 4121 | 4625 5185
> 4840 4574 | 4502 6796
> 6465 6932 | 4558 8233
> 6966 7222 | 4955 8237
> 7551 7219 | 9115 8269
> 8315 7168 | 43171 8340
> 9102 7136 | 57920 8349
> -------------------------------------------------------
> 6362 6054 | 16775 7333
>
>
Sorry, I haven't followed this thread at all, but the numbers (43171 and
57920) in the last two runs of @mv-free-list for 32 clients look
aberrations, no ? I wonder if that's skewing the average.

I also looked at the the Results.htm file down thread. There seem to be a
steep degradation when the shared buffers are increased from 5GB to 10GB,
both with and without the patch. Is that expected ? If so, isn't that worth
investigating and possibly even fixing before we do anything else ?

Thanks,
Pavan