MySQL 5 32-bit vs 64-bit performance?

I've tried searching online for performance comparisons between MySQL
32 and 64-bit platforms, but can only find benchmarks dating back a
few years using MySQL 4.x . Now we're on MySQL 5.0 and I cannot seem
to find such evidence backing up the speed benefits (or otherwise) of
a 64-bit processor.

We've got the MySQL Enterprise 64-bit version running on an Intel Core
Duo based server system. However, a Chinese language fulltext search
patch being developed by MySQL in China is to be installed for us -
but only the 32-bit version of MySQL is currently available, which
effectively means downgrading if I want to benefit from that patch.

- but I cannot find evidence of whether 64-bit is even beneficial in
the first place.

Anyone able to give me some semi-concrete performance comparisons?

Thanks!

Terence

terence.parker@gmail.com wrote:
> I've tried searching online for performance comparisons between MySQL
> 32 and 64-bit platforms, but can only find benchmarks dating back a
> few years using MySQL 4.x . Now we're on MySQL 5.0 and I cannot seem
> to find such evidence backing up the speed benefits (or otherwise) of
> a 64-bit processor.

IANAL, but unless you have more than 4 gig of memory, you really don't get a
gain from a 64bit OS vs. a 32bit. There are performance hits to look past the 4
gig window with a 32bit OS. In a 2 gig box, their is almost imperceptable
overhead of the 64bit OS, yet you have to also endure the lack of hardware
driver intergration, so you buy yourself trouble for no gain.

Walter Vaughan schrieb:
> IANAL, but unless you have more than 4 gig of memory, you really don't
> get a gain from a 64bit OS vs. a 32bit.

Not entirely true - in practice, gains can start at >2GB.

That's because half of the address space is usually reserved for shared
libraries, which means that if the OS doesn't use the full 2GB, that
part of main memory simply remains unused.

The above isn't entirely correct; current-day Linux kernels can use 3GB
for applications and 1GB for shared libraries and kernel.
IIRC you still need to recompile the kernel to get that feature, and
some RAM will still remain unused.

Adressing all bytes on current-day disks requires more than 32 bits, so
a 64-bit processor is usually a win for a database. A 64-bit OS can make
that easier to do in practice, though in principle, one should be able
to access the 64-bit registers even with a 32-bit OS.

> There are performance hits to
> look past the 4 gig window with a 32bit OS. In a 2 gig box, their is
> almost imperceptable overhead of the 64bit OS, yet you have to also
> endure the lack of hardware driver intergration,

Agreed.

Jo

On Apr 18, 11:39 pm, Walter Vaughan <wvaug...@steelerubber.com> wrote:
> terence.par...@gmail.com wrote:
> > I've tried searching online for performance comparisons between MySQL
> > 32 and 64-bit platforms, but can only find benchmarks dating back a
> > few years using MySQL 4.x . Now we're on MySQL 5.0 and I cannot seem
> > to find such evidence backing up the speed benefits (or otherwise) of
> > a 64-bit processor.
>
> IANAL, but unless you have more than 4 gig of memory, you really don't get a
> gain from a 64bit OS vs. a 32bit. There are performance hits to look past the 4
> gig window with a 32bit OS. In a 2 gig box, their is almost imperceptable
> overhead of the 64bit OS, yet you have to also endure the lack of hardware
> driver intergration, so you buy yourself trouble for no gain.

Thanks for that...

Our server currently has 4gb memory but I can't rule out getting more
in the future - I guess that puts us just on the borderline!

I'm not to keen on downgrading to using 32-bit software, but failing
finding a solution to this Chinese language searching plugin I may
have to consider deploying a second server just for searching Chinese.

.... except it would help if federated tables supported FULLTEXT
search.

In any case, thanks for your input!

- Terence