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update obs set uuid = uuid() where uuid is null; |
If you are not using a DB other than mysql, most likely it also has a function to create a uuid. If not, then there is a java routine that runs and uses the java implementation of UUID generation. This is considerably slower, I apologize that you chose an inferior dbms.
There have been issues with mysql on windows and not getting unique uuids [1] . To find those duplicates, you can run this sql:
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