Re: [PATCH] dtrace probes for memory manager - Mailing list pgsql-hackers

From Robert Haas
Subject Re: [PATCH] dtrace probes for memory manager
Date
Msg-id 603c8f070912111012w6e9b38cejeaa809acb7aa7a06@mail.gmail.com
Whole thread Raw
In response to Re: [PATCH] dtrace probes for memory manager  (Zdenek Kotala <Zdenek.Kotala@Sun.COM>)
Responses Re: [PATCH] dtrace probes for memory manager  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Fri, Dec 11, 2009 at 1:04 PM, Zdenek Kotala <Zdenek.Kotala@sun.com> wrote:
> We know that performance impact is less then 1% probably less then 0.6%.
> The question is if it is acceptable or not. I personally think that it
> is acceptable. However if not, I will start work on backup solution with
> dtraced AllocSet and some switching mechanism. But it needs little
> discussion about design. And first we need decision about current
> performance impact.

As far as I am concerned that is way too much, particularly
considering that your test case isn't designed to be particularly
memory-allocation intensive, and if it is up to me I will reject this.Even a quarter-percent slowdown for a feature
thatwill be used only
 
by a small fraction of users only a small fraction of time time seems
totally unacceptable to me.

...Robert


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