PDO extension is written long ago and did not evolve for years.
There is a list of problems with it:
* Absence of non-blocking queries compatible with lib/event
* Violation of a Single Responsibility and Command-Query Separation principles in design
* Weak placeholder implementation
* Difficult query debugging with parameterized queries
* Lack of plugins for Redis and modern databases
Database operations is an essential part of all applications. It need attention.