Re: 7.3.8 under FC3 takes excessive semaphores?

> -----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.


Many thanks,

Mark.

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