Re: PrivateRefCount (for 8.3) - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: PrivateRefCount (for 8.3)
Date
Msg-id 1164658279.3778.303.camel@silverbirch.site
Whole thread Raw
In response to Re: PrivateRefCount (for 8.3)  (Bruce Momjian <bruce@momjian.us>)
Responses Re: PrivateRefCount (for 8.3)  (Bruce Momjian <bruce@momjian.us>)
List pgsql-hackers
On Mon, 2006-11-27 at 14:42 -0500, Bruce Momjian wrote:
> Simon Riggs wrote:
> > int8 still seems like overkjll. When will the ref counts go above 2 on a
> > regular basis? Surely refcount=2 is just chance at the best of times.
> > 
> > Refcount -> 2 bits per value, plus a simple overflow list? That would
> > allow 0,1,2 ref counts plus 3 means look in hashtable to find real
> > refcount.
> 
> At two bits, would we run into contention for the byte by multiple
> backends?

No contention, its a private per-backend data structure. That's why we
want to reduce the size of it so badly.

--  Simon Riggs              EnterpriseDB   http://www.enterprisedb.com




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