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

From Bruce Momjian
Subject Re: PrivateRefCount (for 8.3)
Date
Msg-id 200702202339.l1KNdC603604@momjian.us
Whole thread Raw
In response to Re: PrivateRefCount (for 8.3)  ("Simon Riggs" <simon@2ndquadrant.com>)
Responses Re: PrivateRefCount (for 8.3)
List pgsql-hackers
Added to TODO:

* Consider decreasing the amount of memory used by PrivateRefCount
 http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php
http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php


---------------------------------------------------------------------------

Simon Riggs wrote:
> 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
> 
> 
> 
> ---------------------------(end of broadcast)---------------------------
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--  Bruce Momjian  <bruce@momjian.us>          http://momjian.us EnterpriseDB
http://www.enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +


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