I was so sure my PR#40336 fixed the doctrine-messenger issue once and for all. But it had a very silent bug..

This has been tricky to debug and find because thePDO behaves differently in PHP 7.4 compared to PHP 8.

PR#40055 fixed scenario C on PHP 8, but that also broke scenario B on PHP 7.4 and PHP 8.
In PR#40336 I was wrong claiming:

We don't need COMMIT because the transaction will commit itself when we close the connection.

The result was the we removed all the errors messages from the 3 scenarios. But scenario B will produce some SQL that is actually never committed. IE it will silently fail.

I've been trying to figure out a good solution to how or when to start a transaction. I tried out@fbourigaultsuggestion but that would be the same fix as#40055.

We need a transaction because the SQL includes aLOCK TABLE, however, I cannot see a strict need for it. This PR removesLOCK TABLE and all transaction juggling. It all seams to work.

I would be happy to get thorough feedback on this PR so we can end the chapter of constantly adding bugs to this part of the component.

@dunglas, you addedLOCK TABLE in your initial version of this class in#35485, could you share some knowledge if this is a good or bad idea?