Thanks for your suggestions. I first tried the periodic timer, but I somehow did not get it working for the child-processes: altough I started a timer in each child, and the timer-method was even executed per child, it was always executed in the same process (verified with getpid()), so that the "postponed" initialization happen only in one process.
Anyhow, I then focussed on another approach, where the initialization is triggered with each sql-query, instead of periodically (which is anyway the more efficient way). A first version worked quite well in my tests, and I am already trying to figure out how to open a PR ;-)