If you create a wiki page containing a link to a very long page name, such as

[[This is a really long page name. It goes on and on and on and on. In fact it's not so much a name as a paragraph. I just want to keep typing! Forever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever and ever!]]

then this causes database errors because the name is more than 255 characters long.

My proposed solution is to limit page name length to 200 characters; if you specify a longer link (such as the above) then only the first 200 characters will actually be a link. I might be nice and make it cut off at word boundary a la shorten_text, not sure.