> If that happens to be a bottleneck and you can do better, you should definitely do it in code locally. But these are two ifs that need to evaluate to true
If the OP said what you are saying, I'd probably agree. However, the above statement makes it clear that the OP is saying "put it in the database unless you can prove it doesn't belong there".
That is what I disagree with. There's a lot of reasonable things you can do with a database which aren't the best thing to do from both a system and performance perspective. It is, for example, reasonable to use the sort method on a database. It's also not something you should do without proper covering indexes. Especially if the application can reasonably do the same sort.
"Sometimes it is better to make the database do something, sometimes it isn't. When that is true is context and situation dependent."
"if it can be reasonably done in the database, it should be done by the database”"
In other words, sometimes it's reasonably better to make the database do something, and sometimes it's unreasonable. Context dependent, of course.