Dual CPU with MS Access

[Guest]

Dear Users,

How does Access Developers take advantage of Dual CPU machines? How could I
divide processing between the two CPUs?

Kind Regards
Charles

 

[Douglas J. Steele]

I don't believe Access can take advantage.

 

[Albert D. Kallal]

I cannot EVER remember a situation where ms-access (in a machine with a 1 or
faster ghz processor) needed ANY more processing.

ms-access can even execute in excess of 30 million VB instructions in one
second.

CPU performance has not been an issue for ms-access for a number of years,
and adding a faster processor will do absolute NOTHING to speed up a
ms-access applications.

If you are looking to increase database performance, processing is about the
last place to look these days.

The largest benefits will be from removing i/o bottle necks.....as
processing is rather abundant, and not something that will make any
difference these days (beyond what we get in a standard windows box to day).
Ms-access is i/o bound..not processing bound. To speed things up, you need
to look at network speed (or reducing the amount of data transfered)...not
the cpu....

 

[Stephen Haley]

Well thats the theory and now the practice.
I used a dp box for access and got a decent speed increase out of it roughly
20-40%. This was a VERY large access database or rather 5 of them stiched
together and some had tables with over 1x10^6 records. I use a dp as a
desktop as well and what is noticeable is that while access doesnt take use
of the DP it now has the ability to hog a cpu all to its own and the PC
still has a cpu left for graphics,lan and disk io. In additon the front end
that was running on this box was far more responsive. I suspect that DAO/JET
may be capable on running on one while the front end runs on the other and
you see large performance gains in losing the time that it used to take to
cede processor resources to each other but this may be hogwash, all I can
say is that it ran a lot better and didnt crash when under extreme load. For
sure there was a major benefit somewhere. But this was a semi self contained
system that did a huge amount of processing on the back end, we did have a
front end client for monitor and control and that saw some benefit but
mostly from the back end not running out of cpu.
BUT it is only worthwhile if you are in the same situation with access
talking to a file on the same PC if you are across a lan then unless it is a
dedicated 1gb segment then it is like to be worthless.

rgds
Stephen

 

[david epsom dot com dot au]

DAO Jet is multi-threaded, and will run background thread(s)
updating the data cache, or writing the data cache back to
the file system, while doing select or update queries on a
foreground thread. However, wether that can take advantage
of multiple processors is a moot point: thread locking may
mean that multiple threads like that actually run better
on a single processor.

However, the file system (which jet uses for read/write
lock operations on physical records in the database files)
is normally asynchronous, and, absent any unfortunate thread
locking problems, you would hope that Jet would run better
if the file system was running on a separate processor
from the Jet threads.

I remember that the default state was for applications
to run on one processor, and the O/S to run on the other
processor: it might be that this is still the case.

(david)

 

[Albert D. Kallal]

Well thats the theory and now the practice.
I used a dp box for access and got a decent speed increase out of it
roughly 20-40%. This was a VERY large access database or rather 5 of them
stiched together and some had tables with over 1x10^6 records.

That is rather impressive!!

I use a dp as a desktop as well and what is noticeable is that while
access doesnt take use of the DP it now has the ability to hog a cpu all
to its own and the PC still has a cpu left for graphics,lan and disk io

Sure, that again is fair. Do note that acces97 would often hog 100% of the
cup, but did concede its processing to other tasks.

Versions after a97 are much better in terms of releasing the cpu.


.. In addition the front end

that was running on this box was far more responsive. I suspect that
DAO/JET may be capable on running on one while the front end runs on the
other and you see large performance gains in losing the time that it used
to take to cede processor resources to each other but this may be hogwash,
all I can say is that it ran a lot better and didnt crash when under
extreme load. For sure there was a major benefit somewhere.

Yes, no doubt, a newer machine, better os, better memory management etc. all
contribute to a better platform (windows XP is far more stable, and can use
memory MUCH better then win98 for example).

I guess I am just pointing out that processing speed along is not the real
solution here. However, on a good new machine with faster memory, faster
hard disk, and have transfer rates from memory to processor etc, you do
overall get a decent improvement, and your experience is a excellent example
of this.

So, you point is well taken!!

However, *just* the issue of processing is usually not the solution on its
own to really speed things up...