No, but you did talk about it

To be more precise, I am actually allocating the object on thread symbol table, but under mod_perl objects in "main" threads functions are persistent between calls. So it gets messed on subsequent calls

So you're using a threaded apache, big deal, each perl interpreter instance is still independent of each other-- no threading issue

Actually the issue is about object persistence. I put too much implicit meanings in my initial post, sorry for this.