[ic] Database values changing during a job

[Grant]

I have a job that allocates available inventory to orders based on a
bunch of different factors.  It takes about 20 minutes to run and it's
run every hour.  The problem is, if certain values change during the
job's execution, it will be thrown off.

I thought of setting up a cache of certain values before the job is
run and comparing them when the job is complete so the job can be
re-run if anything has changed.  Alternatively, is there anything
built into mysql that I could use to straighten this out?

- Grant