Index Pool Resynchronization is the process of reinitializing the table /HSGRP1/MATCHKEY.
If there are records created during a downtime of some sort, there is a possibility that
the search process will not provide complete results. Upon creation, update, or
search, automatic resynchronization will take place to update the index. If the
number of unsync records exceeds the set threshold, you will be prompted to
choose whether to continue the resync process or not.