How does Elastic compare with DuckDB?

I know that Elastic is still the most downloaded search engine.

However, I see some users on Medium trying to replace Elastic by DuckDB ...

It is kind of anti-pattern ?
Or may be it is relevant approach only for very small dataset ?

Thank you

As far as I can see they target completely different use cases, so any general comparison is in my opinion likely of limited use. You probably need to evaluate them based on your particular use case.