[fel64]

Serializing data is only bad if you are going to be constantly unserializing it in the same bbpress instance.

_Anything_ is bad if you do it unnecessarily. I don’t understand why you were unhappy with serialising earlier in this case.

Obviously topicmeta is there to be used for topicmeta. That doesn’t mean it needs to store everything that could be construed as topicmeta. My question wasn’t what where the orthodox place to store topicmeta was, but a comparison of unserialising very large arrays vs. a single query. But then I think that serialising is linear, anyway, so it probably remains very good value.