On Sun, 2010-04-25 at 12:51 -0400, Tom Lane wrote: > Simon Riggs <si...@2ndquadrant.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 the + * rule is that updates of head and tail of the array require ProcArrayLock + * in exclusive mode or (shared mode and known_assigned_xids_lck spinlock)" 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 -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
