Another issue what can arise with mySQL and why I advise NOT to use mySQL:

mySQL lacks concept of transactions, as was discussed here or here. Try SuperSearch with "MySQL" and "transaction".

You need transactions-capable database to make changes either in both tables, or none at all in case of any error. What does 'no transactions' means for you?

If something will go wrong, you may eliminate item from the queue, but related info will not be eliminated, or vice versa: related is out, item still in queue. Then next time - guess what can happen?

Remember Murphy's law: If anything can go wrong, it will.

pmas

To make errors is human. But to make million errors per second, you need a computer.