Re: 7.3.8 under FC3 takes excessive semaphores? - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: 7.3.8 under FC3 takes excessive semaphores?
Date
Msg-id 200502021714.j12HE0I23254@candle.pha.pa.us
Whole thread Raw
In response to Re: 7.3.8 under FC3 takes excessive semaphores?  ("Mark Cave-Ayland" <m.cave-ayland@webbased.co.uk>)
List pgsql-hackers
Mark Cave-Ayland wrote:
> 
> > -----Original Message-----
> > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] 
> > Sent: 31 January 2005 16:35
> > To: Mark Cave-Ayland
> > Cc: pgsql-hackers@postgresql.org
> > Subject: Re: [HACKERS] 7.3.8 under FC3 takes excessive semaphores?
> 
> (cut)
> 
> > Judging by the symptoms, you have built a version with what 
> > we now call --disable-spinlocks; that is, it didn't figure 
> > out how to do assembly TAS on your platform and fell back to 
> > using SysV semaphores for spinlocks. Quite aside from the 
> > drain on semaphores, the performance is going to be 
> > spectacularly bad, so you'd better fix that.
> > 
> >             regards, tom lane
> 
> 
> Hi Tom,
> 
> I'd just about managed to come to the same conclusion before your email
> arrived by spending the afternoon with gdb tracing into the LWLock code :)
> 
> I've just installed 7.4.6 on the same box and this time the spinlocks are
> correctly picked up and everything works as expected. I think rather than
> fixing the 7.3.x source, we'll take the plunge and plan for a complete dump
> and restore of the database cluster over a weekend.

And with 7.4 and later we will throw a configure error if we don't find
native spinlocks so you will have no surprises in the future.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 


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