On Sat, Dec 17, 2011 at 1:00 AM, Jim Nasby <jim(at)nasby(dot)net> wrote:
> I also wonder how much this throws some previous performance tests into suspicion. If it's not uncommon for performance improvement attempts to shift a bottleneck to a different part of the system and marginally hurt performance then we might be throwing away good performance improvement ideas before we should...
I think we are (mostly) OK on this point, at least as far as the work
I've been doing. We've actually had a few previous instances of this
phenomenon - e.g. when I first committed my fastlock patch,
performance actually got worse if you had >40 cores doing read-only
queries, because speeding up the lock manager made it possible for the
spinlock protection SInvalReadLock to mess things up royally.
Nevertheless, we got it committed - and fixed the SInvalReadLock
problem, too. This one is/was somewhat more subtle, but I'm feeling
pretty good about our chances of making at least some further progress
in time for 9.2.
The Enterprise PostgreSQL Company
In response to
pgsql-hackers by date
|Next:||From: Marti Raudsepp||Date: 2011-12-17 17:24:02|
|Subject: Re: [PATCH] Caching for stable expressions with constant
|Previous:||From: Simon Riggs||Date: 2011-12-17 11:53:45|
|Subject: Re: JSON for PG 9.2|