char or varchar?

[Anon]

Has anybody observed any drawbacks to using varchar fields rather than chars? I think I remember the docs saying there's more of a performance hit with varchars - because rows are various sizes it takes longer to retrieve, update, etc. I think I also remember reading that tables become "de-optimized" more quickly.

[smarlowe]

This is HIGHLY database dependent.

For instance, on Postgresql, the fastest method is to use text type, not char or varchar, and it's the type that the docs recommend you use when you can.

For other databases, each will have speed advantages or disadvantages based on how the internals of the dbms are written.