Re: TOAST usage setting

Zeugswetter Andreas ADI SD wrote:
>
> > > The big question is do we want to drop the target tuple size down
> to
> > > 512, and increase the chunk size to 8k for 8.3? Dropping the tuple
> > > size down to 512 is going to give us some smaller TOAST values to
> fill
> > > in free space created by the 8k chuck size, assuming you have both
> > > types of values in the table. Do we want to increase the access
> time
> > > of long TOAST by 6% if it means having more wasted space for lots of
>
> > > 4.1k values?
> >
> > If we do that people could see their disk space usage increase by up
> to
> > 16x: currently 513 bytes fits in heap and takes (roughly) 513
> > bytes;
>
> No, you misunderstood. Bruce was suggesting changing the target to 512.
> That means if a row is wider than ~2k, toaster will try to toast until
> the base row is
> ~512 bytes. I would not do that part for 8.3.

OK, what do you suggest for 8.3? Attached are my suggestion to use 512
and a 4k chunk size, which I think means that 2.7k is the worst values
that has a loss of around 25%.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://www.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +