Hi,
What is the opinion of the list as to the best way of measuring if the following implementation is ok?
http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php As mentioned in earlier mails, this will reduce the per-backend usage of memory by an amount which will be a fraction (single digit percentage) of (
NBuffers * int) size . I have done pgbench/dbt2 runs and I do not see any negative impact because of this. Are there any other suggestions for measuring the backend memory footprint?
Regards,
Nikhils
On 2/21/07, Bruce Momjian <bruce@momjian.us> wrote:
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
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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.
>
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> Simon Riggs
> EnterpriseDB http://www.enterprisedb.com
>
>
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