[AccessD] CPU and locks

On 31 Aug 2006 at 15:40, Steve Capistrant wrote:

> Dear List,
> 
> We have an Access 2000 app that has been running for years at a customer's
> site, provided to 100 users via Citrix profiles.  In daily practice, there
> are usually 5 to 15 people logged in at any given time.
> 
> The techies running the server are belly-aching about resource utilization. 
> They note that CPU utlization per user zips up to 25% or 30% of server
> capacity when they perform routine actions (like applying filter rules to
> search on a form).  It drops down to zero after a second or two.   But they
> say "do the math" -- just 4 users doing stuff is going to completely max out
> our servers.  

There's nothing wrong with an application using lots of CPU cycles if they 
are available as long as it is well written and yields to other 
applications.   This sort of thing doesn't scale linearly.  The only way to 
find out what will "max out" your servers is to keep loading additional 
sessions until you start to see a degradation in performance.

> 
> We (our development team) are scratching our heads.  This is normal for
> Access.  It grabs as much resources as it can get to perform data access
> requests.  And I've never heard of a server blowing up from too many
> simultaneous requests.  Windows is designed to handle process threading
> reasonably well, putting things in  order, assigning priorities, reserving
> some CPU for critical processes, etc.
> 
> Nothing's really changed over the years.  Is it just their awareness that
> has changed?  Are these techies just freaking out because they have a new
> Performance Monitoring tool?  
> 
I suspect you have hit the nail on the head :-)

> The other observation they make that might cause overuse of CPU is something
> new to me:  When you look at START > Control Panel > Adminstrative Tools >
> Computer Management > Shared Folders > Open Files....
> 
> ....they note that most of the MS Access item in this view are showing large
> numbers in the "# of Locks" column.  Ranging from 15 to 42 each.  This is
> something I can't explain.  It's a standard FE/BE deployment, so an ldb gets
> generated at both the FE and BE levels.  But what is this huge number of
> locks?  Stranded ldbs?  Some calculus involving the number of simultaneous
> users?  I told them I'd explore what this meant..
> 

Huge?  They don't know much about databases and record locking, do they?

Since the default MaxLockPerFile for Jet is 9500, I certainly wouldn't be 
getting concerned over a few dozen. (And it's only that small because the 
standard maximum locks per connection on Novell servers is 10,000 and MS 
wanted to avoid problems with accessing data stored on them)

Go to  Tools-Options-Advanced. Set Default Record Locking to "All records" 
and see how many locks you start getting then :-)




> Thank you !
> 
> Steve Capistrant
> Symphony Information Services
> scapistrant at symphonyinfo.com
> www.symphonyinfo.com
> Main: 763-391-7400 ext 801
> Toll Free: 888-357-1373 ext 801
> Direct:  612-237-0075
> 

-- 
Stuart