Re: Reducing overhead of frequent table locks

Simon Riggs wrote:
> On Tue, May 24, 2011 at 6:37 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> 
> >> That being said, it's a slight extra cost for all fast-path lockers to benefit
> >> the strong lockers, so I'm not prepared to guess whether it will pay off.
> >
> > Yeah. ?Basically this entire idea is about trying to make life easier
> > for weak lockers at the expense of making it more difficult for strong
> > lockers. ?I think that's a good trade-off in general, but we might
> > need to wait until we have an actual implementation to judge whether
> > we've turned the dial too far.
> 
> I like this overall concept and like the way this has been described
> with strong and weak locks. It seems very useful to me, since temp
> tables can be skipped. That leaves shared DDL and we have done lots to
> reduce the lock levels held and are looking at further reductions
> also. I think even quite extensive delays are worth the trade-off.
> 
> I'd been looking at this also, though hadn't mentioned it previously
> because I found an Oracle patent that discusses dynamically turning on
> and off locking. So that's something to be aware of. IMHO if we
> discuss this in terms of sharing/not sharing locking information then
> it is sufficient to avoid the patent. That patent also discusses the
> locking state change needs to wait longer than required.

FYI, I thought we had agreed not to look at any patents because looking
at them might cause us more problems than not looking at them.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +