We ran into an interesting performance scenario this past
weekend that I have not been able to figure out.

                While our programming staff was working on some of our y2k
updates they found that streaming 3 or more jobs that update our Image
database caused a sever impede problem.  The databases they were working
with were the original and a copy that the y2k changes were written into.
Both databases use Omnidex index keys.  Within the databases, the detail
datasets they were accessing are "stand alone" and do not have any master
datasets associated with them.  They had written a program that opens the
input and output datasets, performs a dataset level lock on both the old and
new databases, then performs a serial read/updates/writes for all the
records, and lastely it releases the locks.  Each run of the program
accessed a different detail set.

                When only two jobs were running at a time there was not
problem.  When the third program was started they started to observe
impedes.  When a fourth job was started the impede situation caused the jobs
to run very slowly.

                Do the wise ones on the list have any thoughts on what could
have caused the impeded jobs?  We do not believe that it was an Image block
since the datasets that were being worked on were not linked to each other.
Beyond that I'm clueless!



Carl McNamee
Systems Administrator
Billing Concepts
7411 John Smith Dr  Suite 200
San Antonio, TX  78229
(210) 949-7282
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