Re: XLogInsert

Greg Smith <greg@2ndquadrant.com>

From: Greg Smith <greg@2ndquadrant.com>
To: Jaime Casanova <jcasanov@systemguards.com.ec>
Cc: Alvaro Herrera <alvherre@commandprompt.com>, Tom Lane <tgl@sss.pgh.pa.us>, Jeff Janes <jeff.janes@gmail.com>, pgsql-hackers@postgresql.org
Date: 2009-12-15T06:16:00Z
Lists: pgsql-hackers
Jaime Casanova wrote:
> So in this extreme case avg tps is just 6 transactions better
>   
Great job trying to find the spot where the code worked better.  I'm not 
so sure I trust pgbench results where the TPS was so low though.  Which 
leads us right back to exactly how Jeff measured his original results.

As I said already, I think we need more insight into Jeff's performance 
report, a way to replicate that test, to look a bit at the latency as 
reported by the updated LWLock patch that Pierre submitted.  Tweaking 
your test to give more useful results is a nice second opinion on top of 
that.  But we're out of time for now, so this patch is getting returned 
with feedback.  I encourage Jeff to resubmit the same patch or a better 
one with a little more data on performance measurements to our final 8.5 
CommitFest in hopes we can confirm this an improvement worth committing.

-- 
Greg Smith    2ndQuadrant   Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com  www.2ndQuadrant.com