angry__panda

Based on my experiments, Postgres switches from scanning the list to a hash when the array size > 8.

This is true for Postgres. But might not be true for other databases. For example, for MySQL, in some cases OR is faster than IN operator based on our experiments.

The article mentioned that it's tested on Postgres 14:

"We used a PostgreSQL v14 database on a db.t3.medium Amazon RDS instance equipped with 2 CPUs and 4GB RAM. The storage capacity is 200GB (gp2 storage)."