/%post_name%/ or /%postname%/ in Permalinks?

Question

In Settings-->Permalinks is there any difference between:

checking Custom Structure and using:

/%post_name%/

or

/%postname%/

Are they both correct? Will they both work?

Thank you.

-Laxmidi

Answer 1

/%postname%/ is the correct one and if you are asking be cause it says post_name in the codex then its just to show that you will get the actual post name.

Answer 2

I just read a really good and informative article suggesting you should never use /%postname%/ I've used that since the beginning for SEO reasons. I've heard arguments throughout the years suggesting this was a bad idea. After reading the article I'm linking to I immediatley switched all sites I'm associated with to /%post_id%/%postname%/ The article suggests that using the old way can cause a large increase DB queries.

There are some pretty respected names in this discussion, all are in agreement. It sounds like it might be resolved with V 3.3, but I've decided not to take a chance. Here is the link: Digging Into WordPres Article