Clinging to sanity, gib@edgate.com (John Gibson) mumbled into her beard:
> I need to upgrade my dual Xeon PostgreSQL engine.
>
> Assuming similar memory and disk sub-systems, I am considering a
> Quad Xeon system vs. a Dual Itanium for PostgreSQL. I believe that
> the PostgreSQL code is written for 32 bit and not optimized for the
> 64 bit Itanium cpu. That makes me think that the Xeon system would
> be a better choice.
>
> Do any of you have thoughts on:
>
> 1. Straight performance capability
> 2. Price/Performance
First thing: What, in particular, makes you think that PostgreSQL code
was written to make it slower or otherwise more restrictive on 64 bit
systems than it needs to be?
Lots of people have been running it on 64 bit systems for _years_ now.
The Digital Alpha architecture, for instance, was introduced in the
1992, and Sun UltraSPARC in 1995. PostgreSQL has been running well on
these sorts of systems for a lot of years now.
Your belief of it being "written for 32 bit" should fly away in the
wake of that.
Secondly, there's a significant counterargument to this, on Intel,
when you look at memory availability.
I have been tearing hair out with some FreeBSD testing in that I have
some quad Xeon systems with 8GB of memory, which gives me the dilemma
of choosing between:
a) Ignoring 4GB of it, or
b) Not having disk connected.
The problem is that having large amounts of memory requires invoking
an Intel "hack" (on FreeBSD, the option is called "PAE"), which
happens to break the disk subsystem. (At least for the controller I
have got.)
And irrespective of any "successful hacks," you are still limited to
either 2GB or 4GB of memory for the postmaster.
If you jump into a 64 bit platform, those sorts of hacks evaporate as
unnecessary, and the main process can get as big as you need it to.
--
(format nil "~S@~S" "cbbrowne" "acm.org")
http://www.ntlug.org/~cbbrowne/rdbms.html
``God decided to take the devil to court and settle their differences
once and for all. When Satan heard of this, he grinned and said, "And
just where do you think you're going to find a lawyer?"''
