Don't know if there's a thread on this.
Katy's ASCAP account, where just about all songs Katy wrote and performed is registered, is a public record that can be viewed by anyone. ASCAP is a music performance rights organization. Other performance rights organizations are BMI and SESAC. Katy's music is registered mainly with ASCAP
Here's how you can access Katy's public record on ASCAP
1. Go to http://www.ascap.com/
2. Click on ACE/Repertory Go button
3. Type Katy Perry into the search window. Also select Writers or Performers.
4. You will see two links, one for Katy Perry, one for Perry, Katy. Click on either one to view the list.
A record also exists under Katy Hudson but shows all the same songs as Katy Perry. No record exists under Katheryn Hudson.
Currently, Katy has 101 songs registered with ASCAP under Writers.