[TylerE]

The concern isn’t the sign of the db on disc but doubling the size of all the indexes in memory

[sgarland]

Or if it’s MySQL, the PK is implicitly copied into every secondary index. Adds up quickly.

[pyuser583]

Wow did not know that. MySQL has tons of hidden behavior.

[sgarland]

So does Postgres to an extent, but in general, MySQL has more hidden edge cases, and Postgres has more hidden maintenance requirements.