Is the object cached?

If you use the WordPress API to retrieve the metadata, then it should be cached for you.

If you do other complex stuff, there is the Transients API for caching data yourself, which will take advantage of whatever object cache you use with WordPress.

EDIT – I should clarify, it’ll be loaded for each request unless you use some sort of caching plugin, though it should load only once for each request.

error code: 521