--- Chuck Esterbrook <[EMAIL PROTECTED]> wrote:
> I added your paper to:
>       http://webware.sourceforge.net/Papers/

> >
> > http://www.opensky.ca/~jdhildeb/webware/
> >

In Jason's paper and elsewhere in the MiddleKit docs there is some
advice on avoiding concurrency issues:

'''
Concurrency Issues

.
.
.

If it is likely that two users will attempt to manipulate the same
object, you may want to implement a locking mechanism to prevent
problems from occurring.
'''

During some stress testing a few days ago I found that if two servlets
are updating or inserting different records at the same time using a
single store, then a store.saveChanges() from either of the servlets
writes all updated records in the store to the database.

So for any updates, it is best to either use unique stores or put locks
around the update operations.  Not doing so may result in bad things
happening, the most noticeable in my tests was an abend in
ObjectStore.py when an assert caught a positive serial number in an
object which was about to be added to the database.

Roger

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