Why arrays are preferable over m2m tables? What so special about pg arrays that makes anything but them inferior in "tagging" case? I genuinely don't get it.
https://shon.github.io/2015/12/21/postgres_array_performance...
https://gist.github.com/joevandyk/031cf5812bd656887623
To search for a post with multiple tags, you need to do a join for each tag. You don't have that problem with arrays.