Architecturally, MySQL went with a “the storage engine is a plug-in” and Postgres went with a more traditional “the storage is part of the core”. Postgres has

Architecturally, MySQL went with a “the storage engine is a plug-in” and Postgres went with a more traditional “the storage is part of the core”. Postgres has slowly grown some ... tolerance ... for alternative storage engines, via federation and forks like greenplum and timescaledb that put their own engines in, but they are always feeling like second class citizens and hitting integration limits.