Re: logging in high performance systems.

Excerpts from Marti Raudsepp's message of mar ene 17 12:12:50 -0300 2012:
> On Thu, Nov 24, 2011 at 04:28, Theo Schlossnagle <jesus@omniti.com> wrote:
> > So... here's my first whack at solving this with some flexibility.
> >
> > The first thing I did was add hook points where immediate statement
> > logging happens "pre_exec" and those that present duration
> > "post_exec".  These should, with optimization turned on, have only a
> > few instructions of impact when no hooks are registered (we could
> > hoist the branch outside the function call if that were identified as
> > an issue).
>
> Note that the hook mechanism you've built is a departure from how
> other hooks are managed in Postgres. Traditionally hooks are just
> global function pointers, and each consumer is responsible for storing
> the previous value of the hook and chain-calling it in the handler. If
> you want to change this pattern, I think you should start another
> discussion.

Hm.  We already have places doing the other thing, for example
see XactCallback and ExprContextCallback.  Not sure we have an actual
criteria for deciding when to use which.

--
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
PostgreSQL Replication, Consulting, Custom Development, 24x7 support