On Sun, 2010-04-25 at 12:51 -0400, Tom Lane wrote:
> Simon Riggs <simon(at)2ndQuadrant(dot)com> writes:
> > On Sun, 2010-04-25 at 11:50 -0400, Tom Lane wrote:
> >> This needs a redesign before it can be considered committable. I don't
> >> really care whether it makes things faster; it's too complicated and too
> >> poorly documented to be maintainable.
> > There are more than 60 lines of header comment explaining in detail how
> > this works, with a full algorithmic analysis. The remaining code is
> > commented to project standards, with easily more than 100 lines of
> > comments.
> If the comments were correct, I wouldn't be complaining. They're
> misleading or outright wrong on many points. In particular, I don't
> think you actually understand the weak-memory-ordering issue, because
> the comments about that are entirely wrong.
The comments says "on CPUs with
+ * weak-memory ordering we can't reliably move pointers atomically, so
+ * rule is that updates of head and tail of the array require
+ * in exclusive mode or (shared mode and known_assigned_xids_lck
I will reword this, so it is clear that I'm talking about the head and
tail of the array, not pointers in general.
Simon Riggs www.2ndQuadrant.com
In response to
pgsql-hackers by date
|Next:||From: Tom Lane||Date: 2010-04-25 17:33:24|
|Subject: Re: testing HS/SR - 1 vs 2 performance |
|Previous:||From: Simon Riggs||Date: 2010-04-25 16:54:59|
|Subject: Re: testing HS/SR - 1 vs 2 performance|