Re: [PATCH] SQL assertions prototype

Andres Freund wrote:
> On 2013-12-18 13:44:15 -0300, Alvaro Herrera wrote:
> > Heikki Linnakangas wrote:
> > 
> > > Ah, I see. You don't need to block anyone else from modifying the
> > > table, you just need to block anyone else from committing a
> > > transaction that had modified the table. So the locks shouldn't
> > > interfere with regular table locks. A ShareUpdateExclusiveLock on
> > > the assertion should do it.
> > 
> > Causing serialization of transaction commit just because a single
> > assertion exists in the database seems too much of a hit, so looking for
> > optimization opportunities seems appropriate.
> 
> It would only force serialization for transactions that modify tables
> covered by the assert, that doesn't seem to bad. Anything covered by an
> assert shoulnd't be modified frequently, otherwise you'll run into major
> performance problems.

Well, as presented there is no way (for the system) to tell which tables
are covered by an assertion, is there?  That's my point.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
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